MXPA02011154A - Elastic stranded laminate with adhesive bonds and method of manufacture. - Google Patents

Abstract

A laminated article having elastic strands or filaments contained therein for providing elasticity to the article, are provided. The particular adhesive pattern bonds the relatively inelastic nonwoven layers to the more elastic continuous filaments in a pattern that allows adhesive-to-adhesive, adhesive-to-nonwoven layer, and adhesive-to-elastic filament bonding.

Description

LAMINATED ELASTIC STRIP WITH ADHESIVE JOINTS AND MANUFACTURING METHOD The present application claims the benefit of the provisional application of the United States of America series no. 60 / 204,300 filed on May 15, 2000 and is incorporated herein by reference thereto.

FIELD OF THE INVENTION This invention relates to composite and laminated non-woven articles and, in particular, to a process for producing a non-woven elastic and / or relatively inelastic laminate that can be used for a variety of applications such as in diapers, athletic bandages or other products that require a degree of elasticity.

BACKGROUND OF THE INVENTION Compounds of elastic and inelastic materials are commonly made by combining elastics and non-elastic in a rolling process to provide the complete composite with a degree of stretch or elasticity. These elasticized compounds they can then be used as the elastic components for various disposable articles for personal care products such as, for example, diapers, pads, medical bandages and the like.

Generally, when such compounds are formed, a non-elastic material (at least a less elastic material) is joined by bonding to an elastic material (or at least a more elastic material) while the elastic material or sheet is a stretched condition. When the tension on the more elastic material is released, the less elastic component of the combination is allowed to fold in the spaces between the bonding sites. The resulting composite elastic material is stretchable to the extent that the less elastic material collected between the bonding sites allows the more elastic sheet to elongate. Examples of these types of composite rolled articles and materials are set forth in the patents of the United States of America. 4.720415 and 5,385,775, each of which is incorporated herein by reference.

In some laminated and stretchable articles, the elastic strands of the continuous filaments are attached to the sheet materials relatively inelastic while the elastic threads are in a stretched condition. Such elastic continuous filaments may, in certain articles, be placed in the form of a sandwich between two or more relatively inelastic sheets. Relatively inelastic sheets can include non-woven fabrics formed by various meltblown or spunbonded polymers. Examples of such laminates are shown in the patent of the United States of America no. 5,385,775 granted to Wright, which is incorporated here in its entirety by reference to it.

As shown in Wright, the continuous and elastic filaments can be extruded onto a sheet of material that moves horizontally. The continuous filaments are extruded from above the horizontal plane of the sheet material and directly onto the material for attachment thereto.

In other example laminates, after joining the continuous and elastic filaments to the sheet material, which will often be relatively inelastic, the non-elastic nonwoven sheet material / attached elastic continuous filament will then be stretched and another relatively inelastic nonwoven sheet can be attached to the filaments elastics. The forces retaining the elastic continuous filaments in a stretched condition are then released to fold the inelastic nonwoven sheet or sheets between the sheet attachment points. In use, the product can be stretched to expand and not fold the inelastic leaves, but it will return, with the release to the collected and shortened state.

Other lamination processes can also be developed to form a stretchable laminated product of elastic and inelastic materials. For example, the patent of the United States of America does not. 4,910,064 issued to Sabee shows an apparatus for manufacturing an integral filamentary fabric comprising continuous filaments and meltblown fibers. A multiple number of continuous filaments are spun in a curtain type form, one side of which have melt blown fibers deposited thereon and self-bonding to fix the continuous filaments in a controlled alignment. The process involves pulling continuous filaments either before, during or after the deposition of the melt blown fibers in order to molecularly orient the continuous filaments. After stabilizing the continuous and elastic filaments by binding to the blown fibers with Fusing and relaxing the filaments, the elastic filaments and the tissue contract to form curls, loops, or twists in the permanently elongated continuous filaments and molecularly oriented non-elastic. The patent further discloses the joining of a second meltblown fabric opposed to the opposite side of the continuous filaments after the continuous filament / meltblown composite is partially pulled to provide some degree of molecular orientation.

In addition, the patents of the United States of America us. 5,200,246 and 5,219,633 also given to Sabee, show a vertically oriented process and apparatus for producing a fabric that combines continuous and elongated filaments with fibrous melt blown fabrics to interlock the continuous filaments in an integrated, fibrous continuous filament matrix. An extruder provides molten elastomeric continuous filaments which are cooled, solidified and stretched as they are pulled from the meltblowing nozzle by controlled temperature and counter-rotating pull rolls. The solidified continuous filaments are then subsequently pulled into a pressure point of a pair of temperature controlled reservoir rolls wherein two opposing melt blown fiber and gas streams are simultaneously and turbulently intermingled with each other and between the continuous and tensioned elastomeric filaments. Passing the fabric between the high speed pulling rollers can then also stretch the composite fabric.

In the manufacture of such laminates, the adhesives have been used to hold them and the elastic filaments in place, thereby bonding the elastic filaments or filaments to the nonwoven coating materials. The patent of the United States of America no. 4,880,420 issued to Pomparelli describes a method for applying the adhesive to bond the elastic threads to a fabric by using a sinusoidal line of adhesive. In Pomparelli, a relatively thick part of the adhesive is applied in a long alignment of one or more elastic filaments in a direction generally parallel to the elastic filaments. However, the line of adhesive described in Pomparelli does not intersect itself at any point. Instead, the sinusoidal adhesive line intersects a predetermined number of the same various elastic threads times when the line proceeds on its way through the threads.

One problem in the manufacture of elasticized articles is that the use of adhesives to attach the elastic threads to a non-woven sometimes causes the article to become stiff rather than soft. In diapers, for example, excessive adhesive results in a rigid or non-flexible diaper product that is undesirable to consumers. Also, if the adhesive is not applied in a preferred pattern, and is not used efficiently, it can not achieve optimum performance to provide the higher bond strength for each gram of adhesive applied to the article. Therefore, a challenge in the manufacture of products of this type is to find ways to use less adhesive but still impart sufficient bond strength to securely fix the elastic filaments in a nonwoven.

SYNTHESIS OF THE INVENTION The present invention provides new methods and patterns of applying adhesive materials to laminated articles containing elastic jaiJo. The articles in which the present invention can be used include various articles that require elastic portions such as diapers, caps and absorbent garments, such articles typically will include one or more non-woven layers and a plurality of elastic filaments or yarns attached to the non-woven layer or layers to provide the desired degree of elasticity. Typically, an adhesive material is used to bond the yarns to the non-woven layers. In the joining arrangement of the present invention, the adhesive material is applied in lines intersecting the elastic filaments to form a bonding network composed of adhesive-to-elastic bonds, adhesive-to-coating bonds and adhesive-to-adhesive bonds.

The adhesive patterns used in the present invention will typically be lines lying perpendicular or almost perpendicular to the elastic components. Even when true 90 degree joint angles may be desirable, the average or average joint angle may be as small as 50 degrees, and typically will be approximately 60 degrees. A larger joint angle will generally result in an increased bond strength between the continuous filaments and the non-woven layer to which the filaments are attached.

In the joining arrangement of the present invention, the elastic-adhesive bonds are formed at the points where the adhesive lines and the elastic material meet or intersect and the adhesive-to-adhesive bonds are formed at the points where the adhesive bonds are formed. Adhesive lines intersect or unite themselves.

A particular embodiment in which the present invention can be used is an absorbent article (garment) or an infant diaper in -where less than 0.6 grams of adhesive are applied per article to bond the elastic yarns of the article to the coating layers not contiguous knits. This results in a product that is generally free from unnecessary stiffness while retaining a solid and stable bond of elastic filaments to a non-woven face material.

In one aspect of the invention, a manufacturing process of an absorbent laminate article is utilized. The process comprises providing a non-woven layer and spraying an adhesive onto the surface of the non-woven layer wherein the adhesive is applied to the non-woven layer in a non-random pattern that is capable of provide - predetermined strength characteristics to the structure of the laminate. In addition, the process includes providing a plurality of elastic filaments essentially parallel to one side of the non-woven layer, the elastic filaments being extruded from a matrix in a melted form and then cooled. Finally, the process includes processing (1) the non-woven layer, (2) the elastic filaments, and (3) the adhesive together at a pressure point to form a laminated article.

Other objects such as advantages and applications of the present invention will become clear from the following detailed description of the embodiments of the invention and the accompanying drawings in which the reference numbers refer to similar or equivalent structures.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a particular apparatus for laminating continuous filaments and nonwovens together; Figure 2A shows a cross section of a laminated absorbent article of the invention wherein an adhesive spray has been applied on the surface of a non-woven coating; Figure 2B shows a cross section of a laminated absorbent article of the invention wherein an adhesive spray has been applied on both opposite nonwoven coverings; Figure 3A shows a bonding pattern in which the adhesive has been applied to the elastic filaments with attenuation in the transverse direction.

Figure 3B shows a canvas or spray pattern of adhesive bond; Figure 3C shows another canvas pattern or adhesive bonding spray.

Figure 3D conceptually illustrates the bonding angle in a canvas bonding pattern of this invention.

Figure 4 shows the bonding pattern and the method of calculating the number of joints per unit length on elastic yarns or filaments according to the present invention.

Figure 5A illustrates a swirling type of adhesive bonding pattern.

Figure 5B shows a random adhesive bonding pattern having a majority of adhesive lines in an orientation perpendicular to the elastic filaments.

Figure 5C is a graphic representation of a placed pattern of adhesive with attenuation of adhesive lines in the cross machine direction.

Figure 5D shows a "chain link fence" type pattern of adhesive attached to the elastic filaments; Y Figure 6 is a schematic view of another particular apparatus for laminating continuous filaments and non-woven coatings together.

DEFINITIONS The term "continuous filaments" as used herein, refers to polymer filaments continuously formed. Such filaments will typically be formed by extruding the molten material through a die head having a certain type and arrangement of capillary holes therein.

The term "elastic" or "elasticized" as used herein, refers to a material which, with the application of a pressing force is stretchable, which is elongatable to at least about 60% (for example to a length pressed and stretched which is at least 160 percent of its length not pressed and relaxed) and which will recover at least 55 percent of its extension with the release of the stretching force. A hypothetical example of an elastic material will be one of a one-inch sample of a material which is stretchable to at least 1.60 inches and which, when released, will recover a length of no more than 1.27 inches. Many elastic materials can be lengthened by more than 605 (for example by more than 160 percent of their relaxed length). For example, some of the elastic material can be lengthened 100 percent more and many of these will recover to essentially their initial relaxed length such as, for example, within 105 percent of their original relaxed length with the release of the stretching force.

As used herein, the term "polymer" generally includes but is not limited to homopolymers, copolymers, such as, for example, graft block, random and alternating copolymers, terpolymers, etc. And mixtures and modifications thereof. In addition, the term "polymer" includes all possible geometric configurations of the material such as isotactic, syndiotactic and random symmetry.

The term "composite nonwoven fabric," "composite nonwoven," "laminating" or "non-woven laminate" as used herein, unless otherwise defined, refers to a material having at least one elastic material attached to at least one sheet material. In most such laminate or composite fabric incorporations it will have a recoverable layer which is attached to an elastic layer or material so that the recoverable layer can be folded between the bonding sites. As stated herein, the composite elastic laminate can be stretched to the extent that the recoverable material folding between the joints allows the elastic material to be lengthened. This type of composite elastic laminate is described, for example, in the patent of the United States of America no. 4,720,415 issued by Vander Wielen and others which is hereby incorporated in its entirety by reference thereto.

As used herein, the term "non-woven fabric" refers to a fabric having a structure of individual fibers or threads that are interleaved, but not in a repetitive and identifiable manner. Non-woven fabrics have been formed in the past by means of a variety of processes such as, for example, meltblowing processes, spunbond processes, and carded and bonded tissue processes.

As used herein, the term "melt blown fibers" means fibers formed by extruding a molten thermoplastic material through a plurality of usually circular and fine matrix capillary vessels such as filaments or molten thermoplastic material into a gas stream ( for example air) of high speed which attenuates the filaments of molten thermoplastic material to reduce its diameter which can be to a microfiber diameter.

Then, the meltblown fibers are carried by the high velocity gas stream and are deposited on a harvester surface to form a meltblown fabric and randomly disbursed. Such a process is described, for example, in the patent of the United States of America no. 3,849,241 granted to Butin which is incorporated here in its entirety by reference to it.

As used herein, the term "spunbonded fibers" refers to small diameter fibers formed by extruding a molten thermoplastic material such as filaments from a plurality of thin, usually circular, capillary vessels of a spin organ with the diameter of the extruded filaments then being rapidly reduced such as, for example, by means of eductive stretching or other well-known spin-bonding mechanisms. The production of non-woven fabrics bonded with yarn is illustrated in the patents such as, for example, the patents of the United States of America. 4,340,563 granted by Appel and others and 3,692,618 granted to Dorschner and others. The descriptions of these patents are incorporated herein in their entirety by reference thereto.

As used herein, "canvas" generally refers to the nonwoven fabric or fabric of material which may be elastic or inelastic and having a machine direction oriented along the manufacturing path and a transverse direction.

DETAILED DESCRIPTION OF THE INVENTION Reference will now be made to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, and not as a limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to this invention without departing from the scope or spirit of the invention. For example, the features illustrated or described as part of an embodiment may be used in another embodiment to give even an additional embodiment. Therefore, it is intended that the present invention cover such modifications and variations as fall within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are described in or are obvious from the following detailed description. It is understood by one of ordinary skill in the art that the present discussion is a description of example embodiments only and is not intended to limit the broader aspects of the present invention, the broader aspects of which are involved in the constructions of example.

As mentioned above, elastic ribbed laminates are used in a variety of applications for personal products such as waistbands, leg cuffs, side panels and the like in which a tight but comfortable elastic fit is necessary. Products that require such laminates with elastic threads include disposable diapers, disposable training pants and pants for adult care. Flexible and soft coatings made of materials such as polymer and non-woven films surround the elastomeric polymer yarns in these laminates. Adhesives are commonly used to bond coatings to threads, and coatings to coatings.

One of the particular means for applying adhesives to laminates uses spray technology of blowing with fusion. In this technology, meltblowing equipment presents the adhesive to the laminated layer in a random fibrous configuration. Multiple adhesive-to-adhesive yarn seams per length of elastic unit are formed, along with multiple face-to-face adhesive bonds per unit area. In general, flexible and strong adhesive joints are required to maintain the flexibility of laminate integrity in use. If the adhesive-to-adhesive bonds are very few in number or are very weak, then the elastic tension properties of the laminate will be compromised since the tension of the elastic threads will break the adhesive joints. The common remedy in prior art processes to remedy this condition is to increase the number of bonding sites by either increasing the melt spray air pressure or by slowing down the rolling speed. As the air pressure of the melt spray is increased, the resulting adhesive fiber size is reduced in these known processes, creating weaker bonds. Increasing the amount of adhesive used per unit area to create larger adhesive filaments usually repairs this, but this usually increases the cost of the laminate. Lowering the rolling speed will decreases the productivity of the machine, but negatively impacts the product cost.

Figures 2A and 2B illustrate the use of such melt spray fabrics. In Figure 2A, a cross section of a laminated article produced with the typical melt sprayed adhesive is shown. A laminated article 26 is shown as having a first nonwoven coating 27 and a second nonwoven covering 28. The melt sprayed adhesive layer 29 is applied between the nonwoven coverings, and the continuous elastic filaments 30 are seen in cross section. Figure 2B shows a cross section of a laminated article 32 in which the sprayed and melted adhesive 29 has been applied over both non-woven coatings 27 and 28.

The present invention, however, employs an elastic yarn laminate wherein the number of elastic yarn binding sites are prescribed or predetermined, and elastic to adhesive yarn seams are generally perpendicular to the orientation to provide increased strength. This allows the laminate to be done at a minimum cost by optimizing The content of adhesive and elastomer to meet the needs of the product.

The adhesives are applied according to the present invention in a continuous waveform pattern which intersects the elastic yarns in a predominantly perpendicular manner. The bonding of the continuous adhesive filaments to the elastic yarns at their intersections is also controlled by a known number of elastic yarn lengths of unity so that predicted and controlled laminate properties are achieved. By encapsulating the high-strength adhesive to the elastic yarn joints with a perpendicular orientation and optimizing the number of joints per length of elastic yarn per unit, the elastic yarn laminates per unit, the elastic yarn laminates of the present invention can be produced with only a minimal amount of adhesive and elastomer. In addition, the adhesives are applied in some embodiments of the present invention to obtain both the adhesive-to-elastic bonds and the adhesive-to-adhesive bonds as well as the adhesive-to-coating bonds, with the bonding of adhesive to the adhesive. adhesive contributing to the strength characteristics of the present invention.

Although the invention will be described and shown in the context of a nonwoven / continuous filament forming apparatus which is in a vertical orientation, it is understood that several other apparatuses may be employed in the formation of the laminates. The vertically oriented rolling forming apparatus is shown in Figure 1. This apparatus includes an extruder 15 which forms continuous filaments 14_ and then guides the continuous filaments through a series of rollers until the filaments are placed in position for attachment to the filaments. one or more non-woven coverings. In other embodiments, such as in Figure 6, the series of rollers can be eliminated. Various apparatuses may be employed in the present invention and are described more specifically in the co-pending application owned by the present assignee and bearing serial number 60 / 204,307 and filed on May 15, 2001, as a provisional application (and subsequently filed as an application for utility) with the title: "Method and Apparatus to Produce Laminated Articles". This request (both the provisional application and the corresponding utility application) are incorporated here in their entirety by reference.

Various types of compositions and various processing conditions can be used to form the elastic continuous filaments. For example, the elastic Kraton® brand polymer can be fed to an extruder wherein the polymer is melted at a controlled temperature of between about 260 ° and 460 ° F, and in some cases about 385 ° F. In other embodiments, depending on the particular polymer employed, the melting temperature may be from about 470 ° F to 480 ° F. The polymer is then extruded through a predetermined number of apertures in a die head in a generally downward direction in continuous and spaced filaments at a pressure of about 300 to 4000 pounds per square inch (typically from about 1500 around. of 2000 pounds per square inch).

A particular class of polymers that can be used in the present process is the Kraton® series of polymers distributed by Shell Chemical Company (now available from Kraton products U.S.-LLC) several Kraton® polymers can be used.

In one embodiment, the mixture used to form the elastomeric continuous filaments as well as the coatings include, for example, from about 40 to about 80 weight percent elastomeric polymer, from about 40 to about 80 weight percent elastomeric polymer, from about 5 to about 5 weight percent. 40 percent polyolefin and from about 5 about 40 percent resin resin. For example, a particular composition may include by weight, about 61 to about * 65 percent KRATON® G-1657 (in one case, about 60 percent), about 17 to about 23 percent wax of polyethylene NA 601-04 (in one case, about 20 percent) and about 15 to about 20 percent of REGALREZ ™ 1126 (in one case about 17 percent). G-16567 is, in particular, a triblock polymer of styrene-ethylbutylene-styrene triblock (S-EB-S).

In another embodiment, a polymer blend consisting of about 85% of a tetrablock base rubber polymer A-B-A '-B' (sold as G1730 by Kraton Products) and polyethylene wax NA601 can be employed. In this particular case, A and A 'in the rubber polymer can be thermoplastic blocks containing a styrene moiety and B and B' can be elastomeric polymer blocks consisting of poly (ethylene-propylene).

In a further embodiment, a polymer blend consisting of about 80% tetrablock base rubber polymer A-B-A '-B', 7% polyethylene wax NA601, and 13% REGALREZ ™ 1126 glutinizer can be used. As indicated above, A and A 'in the rubber polymer can be thermoplastic blocks containing a styrene moiety and B and B' can be elastomeric polymer blocks consisting of poly (ethylene-propylene).

In another embodiment, a polymer blend consisting of about 705 of tetrablock base rubber polymer A-B-A '-B' and 30% polyethylene wax in NA601 can be used. As indicated before, A and A 'in the rubber polymer can be thermoplastic blocks containing a styrene moiety and B and B' can be elastomeric polymer blocks consisting of poly (ethylene-propylene).

These various compositions can be used to form both the continuous filaments and the outer coatings joined with spinning. Without However, the present invention is not limited to these or any particular material or polymer from which to form the continuous filaments. For example, various materials, including the following, may be used: polypropylene, polyethylene, polyesters, polyethylene terephthalate, polybutane, polymethyldenedione, ethylenepropylene copolymers, polyamides, tetrablock polymers, styrenic block copolymers, polyhexamethylene adipamide, poly (oc-caproamide) , polyhexamethylene-sebacamide, polyvinyl, polystyrene, polyurethane, thermoplastic polymers, polyfluorochloroethylene, ethylene vinyl acetate polymers, polyether esters, polyurethane, polyurethane elastomers, polyamide elastomers, polyamides, viscoelastic hot melt pressure sensitive adhesives, cotton, rayon, hemp and nylon. In addition, such materials can be used to extrude filaments of single constituent, biconstituent and bicomponent within the scope of the presently described invention.

Other exemplary elastomeric materials that may be used include polyurethane elastomeric materials such as those available under the trademark ESTA E of B.F. Goodrich & Co., materials elastomeric polyamides such as those available under the trademark PEBAX from Rilsan Company, and elastomeric polyester materials such as those available under the trade designation HYTREL from E.l. DuPont De Nemours & Company However, the invention is not limited to only such elastomeric materials. For example, various latent elastic materials such as the Arnitel brand polymers can be used to provide the necessary elasticity characteristics to the continuous filaments.

Several extrusion dies can be used to form the continuous filaments. In addition, several processing tapes and parameters can be employed, depending on the desired characteristics of the final product. For example, the die of the extruder forming the continuous filaments may be positioned with respect to the first roll such that the continuous filaments meet this first roll at a predetermined angle. The angle between the die output of the extruder and the vertical axis (or the horizontal axis of the first roller, depending on which angle is measured) can be as little as a few degrees or as much as 90 °. Angles such as around 20 °, around 35 ° or around 45 ° out from the vertical can be used.

The rollers are positioned and operated so as to cause the continuous filaments to be stretched by vertically flowing these through the roller bank. Each successive roller rotates in a direction opposite the immediately preceding roller so that the continuous filament yarns are driven out of a roller roller. In addition, the speed of each successive roll can be varied from that of the preceding roll so as to obtain the desired stretching and stretching characteristics.

The number of separate rolls used to carry the continuous filaments to the bonding site can vary depending on the particular attributes desired in the final product. In a particular embodiment, at least four rollers - a first cooled (or laying) roller, a second cooled roller, a third uncooled roller and a fourth uncooled roller - can be used. In certain embodiments, the rolls may be plasma coated to provide good release properties. In others Incorporations, the rollers may be additionally grooved or grooved to ensure that the extruded continuous filaments maintain adequate spacing between the individual filaments as said filaments pass over the surface of the rollers and flow through the system. In some embodiments, smooth rollers can be used for one or all rollers. After passing through the cooling rollers (either the series or the one or two of the cooler rollers shown in Fig. 6) and when being drawn, the continuous filaments are then brought to a position so that a material of sheet can be attached to the continuous filaments. In other embodiments, the number of rollers in the series can be significantly reduced. In fact, only one or two cooled rollers may be necessary to achieve the products of the present invention.

In certain embodiments, this sheet material will be less elastic than continuous filaments. The sheet material may be various non-woven fabrics such as meltblown fabrics, knitted fabrics or carded fabrics, various woven fabrics or a film material. Certain increased properties and production efficiencies, however, arise from the use of non-woven fabrics bonded with polymeric yarn. In a particular embodiment, a polypropylene spunbonded coating having a basis weight of about 0.4 ounces per square yard ("osy") may be employed.

The materials used to form the continuous filaments can also be used to form the outer coatings of the laminate currently described. In particular, various fabrics can be used which are formed of elastomeric and non-elastomeric fibers. Various elastic polyester materials are, for example, described in the patent of the United States of America no. 4,741,949 issued to Morman et al., Which is incorporated herein in its entirety by reference thereto. Other useful elastomeric polymers also include, for example, elastic ethylene copolymers and at least one vinyl monomer such as, for example, vinyl acetates, monocarboxylic, aliphatic and saturated acids, and the esters of such monocarboxylic acids. The elastic copolymers and the formation of the elastomeric fibers of these elastic copolymers are described in, for example, the United States patent. of America no. 4,803,117, which is also incorporated herein in its entirety by reference thereto.

The coating or coatings of the present invention can be a mixture of elastic and non-elastic particles or fibers. For example, the patent of the United States of America ng. No. 4,209,563 is incorporated herein by reference thereto and describes the process by which elastomeric and non-elastomeric fibers are blended together to form a single coherent weave of randomly dispersed fibers. Another example of such an elastic composite fabric is shown in U.S. Patent No. 4,741,949 which is also incorporated herein by reference in its entirety wherein an elastic non-woven material is described, including a blend of thermoplastic fibers. blown with fusion and other materials. The fibers and other materials can also be combined in the forming gas stream in which the fibers are carried so that intimate mixing and entanglement of the fibers and other materials occurs, for example wood pulp, basic fibers or particles such as, for example, activated carbon, clays, starches or hydrocolloid (hydrogel) particles prior to the collection of the fibers on a collecting device to form a coherent fabric of fibers dispersed at random.

Various process aids can also be added to the elastomeric polymers used in the present invention. For example, a polyolefin can be mixed with the elastomeric polymer (e.g., the elastomeric block copolymer A.R.A) to improve the processing of the composition. The polyolefin must be one which when mixed is subjected to an appropriate combination of high pressure and high temperature conditions, is extruded in a mixed form with the elastomeric polymer. Useful polyolefin mixing materials include, for example, polyethylene, polypropylene and polybutene, including copolymers of ethylene, copolymers of propylene and copolymers of butene. A particularly useful polyethylene can be obtained from U.S. I. Chemical Company under the trade designation Petrothene NA 601 (also referred to herein as PE NA 601 or polyethylene NA 601). Two or more polyolefins can be used. Extrudable blends of elastomeric polymers and polyolefins are discussed in, for example, U.S. Pat. 4,663,220, which is incorporated herein in its entirety by reference thereto.

The elastomeric materials that are used to form the elastomeric filaments and / or the diffused spray adhesive can have a sufficient tack to improve the bond strength of the laminate by allowing a degree of autogenous bonding. For example, the elastomeric polymer itself can be tacky when formed into fibers and / or filaments or alternatively, a compatible glutinizing resin can be added to the extrudable elastomeric compositions described above to provide the glutinized elastomeric fibers and / or self-attaching filaments. . Various known glutinizing resins and glutinized extrudable elastomeric compositions can be employed, such as those described in the United States of America patent no. 4,787,699, which is incorporated herein in its entirety by reference thereto.

Any glutinizing resin can be used as long as it is compatible with the elastomeric polymer and can withstand extrusion processing conditions. If the elastomeric polymer (for example an elastomeric block copolymer A-B-A) is mixed with processing aids such as, for example, polyolefins or extension oils, The glutinizing resin must also be compatible with those processing aids. Generally, hydrogenated hydrocarbon resins exhibit increased temperature stability and, therefore they can be desirable glutinizing. The glutinizers of the ARKON ™ series and REGALREZ ™ hydrocarbon are examples of hydrogenated hydrocarbon resins. ZONATAK ™ 501 is an example of a terpene hydrocarbon. REGALREZ ™ hydrocarbon resins are available from Hercules Incorporated. Resins of the ARKON ™ series are available from Arakawa Chemical (U.S.A.) Incorporated. Of course, the present invention is not limited to the use of such glutinizing resins, and other glutinizing resins which are compatible with the other components of the composition and which can withstand the processing conditions can also be used.

The adhesive used to bond the continuous filaments to the sheets will be applied to the laminate after the continuous filaments are placed on the sheets. Adhesive lines can be applied by using a stationary spray head capable of forming the predetermined pattern or by using nozzles in motion that are designed to follow the pattern path default required by the adhesive line. In addition, one or more spray heads can be used. Various equipment for applying the adhesive lines of the present invention may be used if the invention is not limited to any particular apparatus.

In general, the adhesive bonds anchoring the elastic yarns in the present laminate are regulated by unit area by means of the application system so that the key properties such as stretching and elongation can be controlled to precisely meet the operating needs of the product.

This invention allows the optimization of the elastomer, the adhesive and the coatings in the laminate, thus providing a preferred hunt for rolling properties and rolling cost. Laminate properties that can be adjusted more precisely with this invention include softness or material fall-a minimum amount of adhesive can be used to provide a less rigid structure. In addition, the tension characteristics of the laminate can be either made to product requirements using the invention because the joints of adhesive can be prescribed and / or predetermined along the elastic threads. Therefore, a minimum number of adhesive bonds can be used in certain embodiments to allow more flexibility in the elastomer. The elongation and retraction properties of the laminate can also be designed to meet product needs by controlling the number of adhesive bonding sites. The level of yarn slipping in the laminate (for example the amount by which the yarns slide between the coatings between the bonding sites) can be regulated to meet the needs of the product by also prescribing the number of adhesive bonding sites . The volume amount of the laminate can also be modulated since the shrinkage and crimping resulting from the coatings can be controlled due in part to the ability to regulate the number of adhesive bonding sites along the elastic yarns.

Adhesives are typically employed in laminates of the type provided by the present invention because the coating materials and elastomeric components are constructed of polymers that often do not readily bond to one another. The use of an external adhesive bonding agent, however, rectify this problem. In addition, the elastomer used to form the continuous filaments can be precomposed with a selected adhesive component that easily migrates to the surface of the elastic, thus the continuous filaments function more like a sheath and core filament. This migration to the surface can provide the necessary binding agent while retaining the elasticity of the elastomer.

Various types of adhesives can be employed in the present invention, including those having elastomeric properties such as adhesives containing Kraton® that are available from Findley Adhesives Company (also known as Bostik Findley). Among the various adhesives that can be used are the Findley H2096 and Findley H2525A brand.

In the absence of autogenous bonding, adhesives can be used to bond coatings to yarns, and coatings to coatings. The particular system and adhesive used can result in a composite fabric composite with improved drape and texture. Various adhesives as discussed herein or otherwise available may be employed in the present system. For some products, such as a wet rolled and stretched and shaped laminated wiper cloth, the use of a high melt flow rate of elastomeric resin of metallocene-catalyzed polyethylene having a low tack can be advantageously used to provide an improved texture and drop. Due to its low melting temperature, such resin is capable of forming a physical interlock when thermally bonded. That is, the resin can penetrate into the porous coatings.

Resins of the Dow Chemical Company having a relatively low density (between about 0.86 and about 0.88 g / cm 3) can be used efficiently in the adhesive system of the present invention. Other Dow resins having lower melt flow rates have also demonstrated the ability to create a physical interlock under thermal bonding conditions. The resin can also be mixed with a lower melt flow glutinizer or elastomer to produce an optimized adhesive system. High melt flow elastomers may be suitable as alternate adhesive systems in the VFL processes described herein.

The system employs pressure point rollers to apply pressure to the coated coating of adhesive and to the continuous filaments to result in the necessary lamination. The outer coating is joined together with the continuous filaments at a fairly high surface pressure, which can be between about 20 and about 300 pounds per linear inch ("pli"). A typical joint pressure can be about 50 pounds per linear inch to about 100 pounds per linear inch.

The joining section, or pressure point roller (sometimes referred to as the "laminator") of the laminating apparatus performs the primary stretching of the continuous filaments. The speed ratio of the pressure point or bond rolls with respect to the cooled rolls can be varied, and in most cases from between about 2: 1 and 8: 1 and in some about 4: 1. to 6: 1.

In certain embodiments, one or more additional coatings may be attached to the other non-clamped surface of the continuous and stretched filaments so as to achieve a stretchable article in which the continuous filaments are placed in the form of sandwich between at least two exterior coatings. Various joining techniques can be used to form this continuous filament / two layer laminate. The adhesive line techniques of the present invention can be employed or melt-spraying techniques can be employed, known, depending on the particular characteristics desired in the final product. The requirement of the present invention is that at least one of the coatings be bonded to the continuous filaments using the predetermined standards described.

Several patents describe various spray apparatus and methods that can be used in supplying melted sprayed adhesive to the coating or outer coatings or, when desired, to the elastic yarns themselves. For example, the following United States patents assigned to Illinois Tool Works, Inc. ("ITW") are directed to various means of spraying or blowing with hot melt adhesive and fibrillated on a substrate: 5,882,573; 5902.540; 5,904,298. These patents are incorporated herein in their entirety by reference thereto. The types of adhesive spraying equipment described in the aforementioned patents are generally efficient for applying the adhesive on the non-woven coatings in the process of this invention. In particular, the ITW-brand Dynatec spray equipment, which is capable of applying about 3 grams per square meter of adhesive to a running cup of about 1100pies per minute, has been successfully used in sprayed adhesive applications and melted contemplated by the present inventive processes.

After the bonding of the coating or coatings to the continuous filaments to form a laminate bonded with spinning / elastomeric continuous filament / spunbonded, the laminate is then allowed to relax and contract to an unstretched or less stretched condition. The laminate is then rolled onto a take-up roller via a surface driven reel. The ratio of the speed of the reel to the reel rollers results in the relaxation of the continuous and stretched filaments and in a retraction of the laminate in a state collected when the laminate is rolled onto the roller. The shrinkage of the continuous filaments results in a stretchable and folded laminate article where the outer coatings are collected between the junctions.

The overall basis weight of the laminate can vary, but in some applications it is between about 2 and about 4 ounces per square yard ("osy"). In a particular embodiment, the basis weight is between about 2.85 and about 3.2 ounces per square yard.

The figure illustrates a vertically shaped example apparatus 11 for forming the continuous filament / filament bonded laminates of the present invention. An extruder 15 is mounted to extrude the continuous melted filaments 14 down from a die at an inclined angle onto the cooled placing roll 12. The cooled placing roll 12. The cooled placement roll 12 ensures proper alignment through the remainder of the system as the filaments spread. As the filaments move on the surface of the cooled placement roller 12 they are cooled and solidified as they move towards and on the cooled surface of the cooled first roller 13. The filaments then move downward in an "s-shaped" progression in this particular incorporation to a second roller 16 and then through the surface of the third roller 17, the fourth roller 18 and up to the pressure point formed by the pressure point roller 19 and the pressure point roller 20.

The continuous filaments can be combined at the pressure point with various types of coatings. In the embodiment shown in Figure 1, a first nonwoven spun bonded coating 22 and a second nonwoven spunbonded cover 24 are combined on the assumed surfaces of the continuous filaments to form a bonded laminate 25. In some embodiments, only A coating can be used, and in other embodiments it is possible to combine the continuous and elastic filaments with three, four more layers of coating material.

Binding of the coatings to the continuous filaments typically occurs by using an adhesive as described above. The adhesive can be applied with a stationary spray head 23 which delivers the adhesive to the surface of at least one of the non-woven spunbonded coatings in a predetermined adhesive line pattern or that can be applied with an adhesive bead on the adhesive. movement (not shown) that is guided on the apparatus to follow the predetermined binding pattern. As shown in the 1, the stationary spray head 23 can be placed on the back side of the point where the cover 22 will meet the continuous filaments 14. The pressure point rollers 19 and 20 can be aligned so that the adhesive 50 can to be applied to the continuous filaments 14 and to the coating 22 as these are put together in the lamination pressure point section. A second spray application head or nozzle (not shown) can be employed in some embodiments to provide one line of adhesive to the other coating 24 to allow attachment to the other surface of the continuous filaments.

Alternatively, the adhesive may be applied to the surface of the non-woven sheet material before the sheet material is placed in contact with the continuous filaments. In this embodiment, the coating carries the adhesive lines until the continuous filaments are placed in adhesive contact at the adhesive bonding points.

In another embodiment of the present system, the aforementioned series of wrapping rolls in itself can be eliminated as shown in Figure 6. In This figure, as in Figure 1, shows an example apparatus in order to carry out the process described above. The VFL 111 system is configured vertically. An extruder 115 is mounted to extrude the continuous molten filaments 114 downward from a die at an inclined angle onto a cooled placement roll 112. The cooled placement roll 112 ensures adequate alignment through the remainder of the system by spreading this filament . When moving the. rf filaments on the surface of the cooled placement roller 112, these are cooled and solidified as they move to and on the cooled surface of the cooled roller 113. As in other embodiments, the filaments then move downward towards the system rolling section comprising a pressure point formed by the pressure point roller 119 and the pressure point roller 120, but in this case it does this without the need for the series of envelope rolls described above. The continuous filaments in this embodiment can be combined at the pressure point with various types of coatings. In the embodiment shown in Figure 6, a first coatings bonded with non-woven yarn 122 and a second coat bonded with non-woven yarn 124 are combined on the opposite surfaces of the yarns. continuous filaments to form a bonded laminate 125. Spunbonded coatings 122 and 124 are provided to the pressure point by a first outer coating roll 127 and a second outer coating roll 128.

The joining of the coatings to the continuous filaments is achieved in this embodiment by the use of two applicators of spray type adhesive. A spray head 123 delivers the adhesive to the surface of at least one of the spin-bonded coatings 122 prior to compression and lamination at the pressure point; and a second spray head 152 applies the adhesive to the bonded coating with nonwoven yarn 124.

The take-up roller 21 (shown in FIG. 1) can be used to receive and wind the continuous laminate of yarn / continuous filament / bonded yarn 25 for storage.

Figure 3A illustrates an exemplary adhesive pattern useful in the present invention in which the adhesive has been applied to the elastic filaments with attenuation of the adhesive lines in the direction transversal to the machine. The pattern 3_5 includes the adhesive lines 36 and the elastic filaments 30. This pattern uses only the bonds of adhesive to elastic.

Figure 3B illustrates another example canvas pattern 38 having the adhesive lines 39 applied to the elastic threads 30 and the adhesive lines 39 themselves. This pattern takes advantage of the additional bond at the points of adhesive to adhesive. In fact, the adhesive overlaps itself in a way -. generally perpendicular to provide a higher bond strength. The angle of union is very high, approaching 90 ° at the intersection between the adhesive and the elastic filaments.

Figure 3C illustrates another canvas pattern - 41 having adhesive lines 42 and continuous elastic threads 30. This incorporation uses adhesive-to-adhesive bonding but not in the extension of the pattern illustrated in Figure 3B.

Figure 3D illustrates the relatively high joint angle that can be employed in products produced according to the present invention. In particular, the positioning angle 44 is shown as . . . ~ 4 * - * - -. » the angle formed by the line of adhesive 48 and the elastic thread 30. The elastic / adhesive angle 46 and the elastic / adhesive angle 45 are shown as being less than 90 °.

Figure 4 uses an example joint pattern to conceptually illustrate the measurement to determine the number of joints per unit length on or elastic filaments. By employing the specified junctions per unit length, several desirable characteristics can be obtained.

Figure 5A shows another exemplary joining pad using the adhesive-to-adhesive bond where a type of swirl of the configuration is employed. Figure 5B illustrates a more random pattern in which a large percentage of adhesive lines are in a perpendicular, or almost perpendicular, orientation with respect to the elastic filaments. Fig. 5C is another exemplary embodiment of a bonding pattern that has no adhesive-to-adhesive bonds, but has numerous elastic-to-thread connections.

Figure 5D illustrates another exemplary bonding pattern having both the adhesive-to-glue bonds adhesive and elastic adhesive-to-thread. The configuration shown in Figure 5D is similar to the design of a chain link fence and provides excellent bond strength.

The present invention can be better understood with reference to the examples given below. However, it should be understood that the invention is not limited thereto.

EXAMPLE 1 In this example, an ITW brand nozzle that has 17 holes was used to create and analyze various characteristics of the spray pattern. In particular, a melting of adhesive polymer was employed (Findley brand H2525A) in various fiber diameters, base weights, and nozzle pressures to determine percent coverage and orientation (eg "anisotropy"). The orientation is the tangent of the average orientation of the spray pattern. In table 1, when the orientation is less than 1,000, then the orientation of the adhesive spray was in the machine direction and when the orientation is more than 1,000, then the orientation of the adhesive spray was in the direction transversal to the machine. When the orientation has a value of 1.00, then the orientation is 45 °, meaning that the orientation is neither dominant in the direction of the machine nor in the direction transverse to the machine. In addition, the coverage is the proportion of presence of adhesive to no presence of adhesive. The "% VOC" is equal to 100 (standard deviation / percent histogram of area-percent) with the smallest coverage% exhibiting better overlap of the adhesive to form the adhesive-to-adhesive bonds. The "formation" is the coefficient of variation for the formation. The fiber diameter is the average fiber size in micro-milliliters.

TABLE 1 EXAMPLE 2 In this example, an ITW brand nozzle having 5 holes per inch was used to create and analyze various spray pattern characteristics. In In particular, an adhesive polymer melt (Findley brand H2525A) was employed as described above at various fiber diameters, base weights and nozzle pressures.

TABLE 2 EXAMPLE 3 In this example, an ITW brand nozzle having 14 holes per inch was used to create and analyze various spray pattern characteristics. In particular, an adhesive polymer melt consisting of the Findley H2096 brand was employed at various fiber diameters, nozzle pressures and base weights as indicated above to determine percent coverage and orientation. The temperature of the adhesive was 360 ° F and the air temperature was 420 ° F. The height of the nozzle above the materials placed was 1.25 inches. As with table 1, when the orientation is less than 1,000, then the spray orientation of adhesive was in the direction of the machine and when the orientation is more than 1,000 then the orientation of the adhesive spray was in the direction transverse to the 4- * machine. In addition, the "% VOC" is equal to 100 (standard deviation / percent histogram of percent-area) with the smallest% coverage exhibiting better overlap of the adhesive to form the adhesive-to-adhesive bonds.

The line speeds of the various samples were varied. The first four samples used a line speed of 500 feet per minute; the next three samples used a line speed of 1000 feet per minute; and the last seven samples used a line speed of 1500 feet per minute.

TABLE 3 It is understood that by one with ordinary skill in the art that the present discussion is of a description of example embodiments only, and that no attempt is made to limit the broader aspects of the present invention, whose broader aspects are involved in the example constructions. The invention is shown by the examples in the appended claims.

Claims (13)

1. A laminated fabric article comprising: (a) a coating layer; (b) a plurality of elastic filaments adjacent a surface of the coating layer; Y (c) an adhesive component, wherein the adhesive component is applied to the surface of the non-woven layer in lines of adhesive, the adhesive lines intersect both the elastic filaments and themselves to form a bonding network composed of joints of adhesive. adhesive to elastic, from layer of adhesive to coating and from joints of adhesive to adhesive.

2. The article of laminated fabric as claimed in clause 1 characterized in that said adhesive lines intersect said elastic filaments at an angle of more than 45 ° and less than 90 °.

3. The laminated fabric article as claimed in clause 1 characterized in that said adhesive lines intersect said elastic filaments at an angle of between about 50 ° and about 90 °.

. The laminated fabric article as claimed in clause 1 characterized in that said adhesive lines intersect said elastic filaments at an angle of between about 60 ° and S &. around 90 °.

5. The laminated fabric article as claimed in clause 1 characterized in that said adhesive lines intersect said elastic filaments at an angle of about 60 °.

6. The laminated fabric article as claimed in clause 1, characterized in that it comprises an additional covering.

7. The laminated fabric article as claimed in clause 1 characterized in that said adhesive component is about 3 about 5 grams per square meter of weight.

8. The laminated fabric article as claimed in clause 1 characterized in that said article has a basis weight of between about 2 to about 4 ounces per square yard.

9. The laminated fabric article as claimed in clause 1 characterized in that the covering layer comprises a non-woven fabric joined with spinning.

10. The laminated fabric article as claimed in clause 6 characterized in that said additional coating comprises a non-woven fabric joined with spinning.

11. The laminated fabric article as claimed in clause 6 characterized in that said continuous filaments and said adhesive component are between said coating layers.

12. A method for manufacturing a laminated fabric article comprising: (a) providing a coating layer; (b) providing a plurality of elastic filaments adjacent a surface of the coating layer; Y (c) applying an adhesive component to bond said elastic filaments to said coating layer in adhesive lines intersecting both the elastic filaments and themselves to form a bonding network composed of adhesive-to-elastic, adhesive-to-adhesive bonds - Coating layer, and adhesive-to-adhesive bonds. * 13 The method as claimed in clause 12, characterized in that it also comprises the steps of: providing a second coating layer and applying an adhesive component to said second coating layer to bond said elastic filaments to said coating layer in adhesive lines intersecting both the elastic filaments and themselves to form a composite bond network of adhesive-to-elastic bonds, adhesive-to-coating, and adhesive-to-adhesive bonds. t