MXPA05006942A - Stretchable film laminates and methods and apparatus for making stretchable film laminates. - Google Patents

Abstract

Stretchable film laminates including a layer of elastomeric openwork, such as a plurality of elastic strands or an elastomeric mesh structure. The stretchable film laminates may include a film layer bonded to the layer of elastomeric openwork, with the film layer having cross-directional stretch and the laminate having a multi-phase stretchability profile. The stretchable film laminates may be made by extruding a film from a die, stretching the film, forming and stretching a layer of elastomeric openwork, conveying the stretched elastomeric openwork onto the film while the film is stretched, and passing the film and the elastomeric openwork through a nip. The invention also includes a machine capable of producing machine-direction, cross-direction, and biaxial stretch materials. The machine includes at least one extruder, at least one filament die and at least one film die both attached to the extruder(s), and at least one nip downstream of the extruder(s).

Description

1 STRETCHABLE FILM LAMINATES AND METHODS AND APPARATUS FOR MAKING STRETCHED FILM LAMINATES This application is a continuation in part of the patent application of the United States of America number 10 / 330,042, filed on December 26, 2002. The description of that prior application is incorporated herein by reference.

Technical Field of the Invention This invention is directed to stretch film laminates and methods and apparatus for making stretch film laminates.

Background of the Invention Stretchable laminates are used in a number of personal care products to make it easier for products to conform to a user's body for an improved fit, and in some steps to protect against filtering. Conventional stretch laminates typically have a layer of elastomeric material, or at most two layers of elastomeric material which are integrated with the extrusion and which are not handled separately in a "green" state before being integrated into the laminate. By the use of only one layer of elastomeric material, or a combination of 2 elastomeric materials each preformed prior to the formation of the stretchable laminate, the stretching capabilities of the resulting laminate are significantly limited.

A technique to improve the stretching of the laminates is achieved through the use of narrowed materials. The terms "constricted" and "stretched and constricted" are used interchangeably to describe a material, such as a non-woven fabric or a laminate that is pulled and stretched in the longitudinal direction thereby reducing its width or its transverse dimension. The controlled pulling can take place under cold temperatures, ambient temperature or higher temperatures and is limited to an increase in the overall dimension in the direction in which it is being pulled up to the elongation required to break the material, which is in many cases about 1.2 to 1.6 times. When it relaxed, the material did not fully return to its original dimensions. The tapering process typically involves unwinding a sheet from a supply roll and passing it through the driven brake pressure roll assembly at a given linear speed. A pick roller or pressure point, which operates at a linear speed higher than that of the brake pressure point roller, pulls the material and generates the necessary tension to lengthen and narrow the material.

In general, a bonded and bonded laminate includes an elastomeric film or filaments attached to a narrowed material in at least two places. The elastomeric film or filaments may be bonded to the constricted material at intermittent points or may be completely attached to the constricted material. Bonding is achieved while the elastic film or filaments and the tapered material are in a juxtaposed configuration. The resulting bonded and bonded laminate is elastic in a direction generally parallel to the direction of narrowing of the constricted material and can be stretched in that direction to the point of breaking of the constricted material or elastic material. The bonded and bound materials are described in greater detail in U.S. Patent No. 5,336,545 issued to Morman, which is incorporated by reference in its entirety in a manner that is consistent with this document.

Another type of stretch laminate is a vertical filament laminate made using a Vertical Filament Lamination (VFL) process, which is described in PCT publication WOOl / 87589, published on November 22, 2001, and entitled ELASTIC THREADED LAMINATE WITH ADHESIVE JOINTS AND MANUFACTURING METHOD by HM Welch and others, incorporated herein by reference. This process involves vertically extruding multiple filaments onto a cooling roller, elongating the filaments, laminating the filaments 4 to a shrinkable fabric (eg carding and bonding) and then letting the filaments shrink thereby creating, for example, a high-flux elastomeric carded and bonded fabric.

The narrow and joined laminates and the vertical filament laminates each have different attributes from each other. Namely, the narrowed and joined laminates are stretched in the transverse direction while the vertical filament laminates are stretchable in the direction of the machine. This may be desirable to have the ability to manufacture both tapered and joined laminates and vertical filament laminates in the same location. However, even when the same type of materials can be used to produce each of these types of laminates, different types of apparatus are required to manufacture each of these types of laminates. Therefore, significant capital and material costs in constructing and maintaining separate machines for narrowed and bonded laminate and vertical filament laminate production lines are expended.

Although the tapered and bonded laminates and vertical filament laminates are suitable for a number of uses, certain applications may benefit from stretched laminates having additional stretch characteristics.

Therefore, there is a need or desire for stretch laminates that have an improved stretch and method for making such stretched laminates.

There is a need or a desire for a single machine that is capable of producing both the tapered and joined laminates and the vertical filament laminates, as well as the stretched and joined and tapered laminates (NSBL's) as taught in the United States patent. United States number 5,116,652 issued to Morman, which is hereby incorporated by reference in its entirety in a manner consistent with this document.

Synthesis of the Invention The present invention is directed to stretch laminates having improved stretch, and to methods for making stretchable materials that have improved stretch. This invention is also directed to a machine capable of producing materials in the direction of the machine, in the transverse direction and biaxially stretched.

Laminates that can be stretched include at least two layers in addition to an elastomeric layer. In certain embodiments, the laminates that can be stretched have a multi-phase stretch profile in the machine direction and / or in the transverse direction. The 6 examples of the materials suitable for at least two layers include the tapered material, the elastomeric material, the inherently spreadable, bicomponent, spunbond and blown fabrics, or a combination of any of these materials. In one embodiment, at least two layers are constricted, with one of the layers narrowed to a greater extent than the other. In a further embodiment, one of at least two layers can withstand greater stress without failing compared to the other layer or layers. The elastomeric layer may be an elastomeric adhesive film, a plurality of elastic yarns either uniformly spaced from one another or zoned, an elastomeric mesh structure, or an elastomer printed in one pattern over another layer.

Laminates that can be stretched can be incorporated into a garment in any suitable capacity, such as in the side panels, ears, waistbands, waist elastics and / or outer covers.

One method for making the stretch laminates include the steps of extruding a film from a die, stretching the film, forming and stretching an elastomeric open work layer, carrying the elastomeric open work and stretching over the film while the film is stretched, and pass the film and open elastomeric work through a pressure point. The film and open open elastomeric work 7 can be stretched to different extensions. The film may be in the form of a plurality of film tapes, a foamed elastomer, an elastomeric adhesive film, or a combination of any of these forms. The elastomeric open work can be in the form of a plurality of elastic yarns, an elastomeric mesh structure, or an elastomer printed in a pattern on a substrate. Additionally, the film and / or the elastomeric open work can be zoned. As yet another alternative, the elastomeric open work may be in the form of a meltblown.

One or more coating layers can be laminated to the film and to the elastomeric open work. The coating layers can be narrowed, such as with one coating layer being narrowed to a greater extent than the other coating layer.

The film can be passed from a first roll to a second roll while a second film is carried from a second die on the second roll on the surface of the first film and the elastomeric open work. One or both of the films can be thinned, narrowed and / or zoned. In certain embodiments, one or both of the films may be a plurality of film ribbons or a foamed elastomer. Additionally, one or more of the layers can be laminated to one or both films. The machine capable of producing the materials stretched in the machine direction, the cross direction and biaxially stretched, include at least one extruder, at least one filament matrix and at least one film matrix both bonded to the extruder or extruders , and at least one pressure point downstream of the extruder or extruders. The machine may also include at least one unwinding. The machine may also include one or more furnaces upstream of the pressure point. Additionally, the machine may include one or more adhesive application areas upstream of the pressure point. In certain embodiments, the machine may include one or more rollers, such as one or more cooling rollers, below the film matrix and / or the filament matrix. In addition, the machine may also include a zone of relaxation down from the pressure point or pressure points. The configuration of the machine is suitable for producing both bonded and tapered laminates and vertical filament laminates.

With the foregoing in mind, it is a feature and an advantage of the invention to provide stretch laminates having improved stretch as well as methods for making such stretch materials. In another feature and advantage of the invention for providing a single machine that is capable of producing stretchable laminates including both rolled and bonded laminates and vertical filament laminates.

Brief Description of the Drawings Figures 1-3 are plan views of various embodiments of the laminate that can be stretched.

Figure 4 is an enlarged cross-sectional view taken along line 4-4 of Figure 3 of another embodiment of a laminate that can be stretched.

Figures 5-7 are amplified cross-sectional views of other embodiments of a laminate that can be stretched.

Figure 8 is a perspective view of an embodiment including stretchable laminates in various locations.

Figure 9 is a schematic view of an embodiment of a method for making a stretch laminate.

Figure 10 is a schematic view of a lattice design roll that can be used to produce an elastomeric mesh structure.

FIG. 1a is an elongation-counter-tension profile of a laminate having a multiple phase stretching profile.

Figures 11b-lld are elongation-counter-tension profiles of three of the layers within the profiled laminate in Figure Ia.

Figure 12a is an elongation-counter-tension profile of another laminate having a multi-phase stretch profile.

Figures 12b-12d are elongation-counter-tension profiles of three of the layers within the profiled laminate in Figure 12a.

Figure 13a is an elongation-counter-tension profile of yet another laminate having a multi-phase stretch profile.

Figures I3b-13d are elongation-counter-tension profiles of three of the layers within the laminated profile in Figure 13a.

Figure 14 is a schematic view of an embodiment of a machine that can produce stretch materials in the machine direction, in the transverse direction and biaxially stretched.

Figure 15 is a schematic view of another embodiment of a machine that can produce materials stretched in the machine direction, in the transverse direction and biaxially stretched.

Definitions Within the context of this description, each of the terms or phrases below shall include the following meaning or meanings.

"Biaxial stretching" refers to the ability to be stretched in both, the transverse direction and the direction of the machine, and potentially in any direction between the transverse direction and the machine direction. "joined" refers to the joining, adhesion, connection, fastening or the like of at least two elements. The two elements will be considered to be joined together when they are directly linked to one another or indirectly to one another, such as when one is directly linked to intermediate elements.

"Elastomeric" and "elastic" are used interchangeably to refer to a material or compound that is generally capable of recovering its shape after deformation when the deforming force is removed. Specifically, as used herein, elastic or elastomeric is intended to be that property of any material which, with application of the pressing force, allows the material to be stretched to a pressed and stretched length which is at least about 50% greater than its relaxed unpressured length and which will cause the material to recover at least 40% of its elongation with the release of the stretching force. A hypothetical example which can satisfy this definition of an elastomeric material will be a sample of one (1) inch of material, which can be lengthened to at least 1.50 inches which, having been lengthened to 1.50 inches and released, it will recover to a length of less than 1.30 inches. Many elastic materials can therefore be stretched, such as 50% of their relaxed length, and many of these will essentially recover their relaxed length with the release of the stretching force. "film" generally refers to a thermoplastic film that makes use of a film extrusion process, such as an extrusion process of set film or blown film. The film can be made thermoset after extrusion using crosslinking technologies known in the industry. The term includes 13 perforated films, cut films and other porous films which constitute liquid transfer films, as well as microporous films which do not transfer the liquid but which transfer water vapor or other gases. "garment" includes garments for personal care, medical garments, and the like. The term "disposable garment" includes garments which are typically discarded after 1-5 times of use. The term "personal care garment" includes diapers, training briefs, swimwear, absorbent underpants, adult incontinence products, women's hygiene products and the like. The term "medical garment" includes medical (for example protective and / or surgical) suits, caps, gloves, covers, face masks and the like. The term "industrial workwear" includes lab coats, coveralls and the like. "layer" when used in the singular may have the dual meaning of a single element or a plurality of elements. "machine direction" as applied to a film or a non-woven machine refers to the direction of the film or nonwoven that was parallel to the direction of travel of the film or nonwoven when leaving the latter. extrusion or training apparatus. If the 14 film or the nonwoven passed between the pressure point rollers or the cooling rollers, the direction of the machine is the direction on the film or the nonwoven that was parallel to the surface of the roller pavement when it did contact with the film or non-woven, "transverse direction" refers to a direction perpendicular to the direction of the machine. The dimensions measured in the transverse direction are referred to as "width" dimensions, while the dimensions measured in the machine direction are referred to as "length" dimensions.

"Melt-blown fiber" refers to fibers formed by extruding a molten thermoplastic material through a plurality of thin, usually circular capillary blood vessels, such as melted threads or filaments into gas streams (eg, air). high speed and convergent which attenuate the filaments of molten thermoplastic material to reduce its diameter, which can be a microfiber diameter. Then, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a randomly dispersed meltblown fabric, such as a process as described in the United States patent. United States of America number 3,849,241 granted to Butxn and others, which was incorporated here in its entirety by reference. The melt blown fibers are microfibers which may be continuous or non-continuous, are generally smaller than about 0.2 denier, and are generally self-bonding when deposited on a collection surface.

The "mesh structure" refers to a type of open work structure made of overlapping or entangled threads, or a continuous layer, in whose discrete opening between the top and bottom surface of the structure are present either in a pattern uniform or in a non-uniform pattern.

"Narrow material" refers to any material which has been pulled in at least one dimension (for example in the longitudinal direction), reducing the transverse dimension (for example the width) so that when the pulling force is removed it has a Higher base weight per unit area than non-constricted material. When the constricted material is pulled back to its original width, it must have about the same base weight as the non-constricted material. This differs from stretching / orienting the film layer during which the film is thinned and the basis weight is reduced.

"Nonwoven" and "non-woven fabric" refer to materials and fabrics of material having a structure of individual fibers or filaments which are interleaved, but not in an identifiable manner as in a knitted fabric. The terms "fibers" and "filament" are used interchangeably herein. Weaves or non-woven fabrics have been formed from many processes such as, for example, meltblowing processes, spinning processes, air laying processes and carding and bonding processes. The basis weight of non-woven fabrics is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm) and fiber diameters are usually expressed in microns. (Note that to convert ounces per square yard to grams per square meter multiply ounces per square yard by 33.91).

"Open work" refers to a layer having visible openings between the top and bottom surface of the layer, such as a layer of parallel threads or a layer of mesh or the like.

"Cinto" refers to a strip of film having a width comparable to a thread, fiber, filament, cable, rope, thread, cord or the like.

"Spunbonded fiber" refers to fibers of small diameter which are formed by extruding a molten thermoplastic material such as filaments of a plurality of capillary bases of a spinning organ having a circular or other configuration, with the diameter of the fibers. extruded filaments then being rapidly reduced as taught, for example in U.S. Patent Nos. 4,340,563 issued to Appel et al. and 3,692,618 issued to Dorschner et al., 3,802,817 issued to Matsuki et al .; 3,338,992 and 3,341,394 granted to Kinney; 3,502,763 awarded to Hartman; 3,502,538 granted to Petersen and 3,542,615 granted to Dobo and others, each of which is incorporated herein in its entirety by reference. Spunbonded fibers are hardened and generally non-tacky when they are deposited on a collecting surface. Spunbonded fibers are generally continuous and often have average diameters greater than about 0.3, more particularly between about 0.6 and 10. Spunbond fibers may be monofilaments or multicomponents such as in the case of fibers joined with bicomponent yarn with a side-by-side or sheath-core configuration or an island configuration at sea as an example of multicomponent.

"Threads" refers to an article of manufacture whose width is comparable to a rope, fiber, filament, cable, rope, thread, cord or the like.

"Stretchable" or "stretchable" means that a material may be stretched, without breaking it by at least 30% (or at least 130% of its initial length (not stretched)) in at least one direction, suitably at least 50% (to at least 150% of its initial length), or at least 100% 18 (to at least 200% of its initial length). The term elastic materials includes, at least 100% (at least 200% of * their initial length). The term includes elastic materials as well as materials that stretch but do not retract significantly. A hypothetical example may meet this definition of extendable materials shall be one of a one-inch material sample which may be at least 30% longer than at least 1.30 inches.

"Butt stretch" refers to a certain proportion of the difference between. the extended dimension of a stretchable laminate and the maximum extended dimension of a stretchable laminate with the application of a specific tensioning force and dividing the difference by the non-stretched dimension of the stretchable laminate. If the stretch to the top is expressed in percent, this ratio is multiplied by 100. For example, a stretchable laminate having a non-extended length of 12.7 cm and a maximum extended length of 25.4 cm with the application of a force of 2,000 grams has a 100% stretch to the top (to 2000 grams). Stretching to the stop can also be referred to as "maximum non-destructive elongation". The maximum non-destructive elongation will apply in the case of a material that has more than one stretch at the top perceived due to its construction. Unless otherwise specified, the top stretch values are reported there at a load of 2000 grams. In the case of more than one stretch to the perceived top, the maximum stretch load or maximum non-destructive elongation value may occur at less than 2000 grams. In the test of elongation or stretching to the top, a 7.62 cm by 17.78 sample, with a larger dimension being the machine direction, the transverse direction or any direction in between them is placed in the jaws of a Sintech machine using a separation of 5 cm between the jaws. The sample is then pulled to a top load of 2000 grams with a crosshead speed of about 20 inches / minute (50.8 cm / minute).

"Upstream" refers to a point in a process er to the beginning of the process relative to the point of comparison. Conversely, "downstream" refers to a point in a process er to the end of the process with respect to the point of comparison.

"Zoned" refers to non-uniform application, such as at non-uniform spacing between the yarns or inks or non-uniform extrusion, heat treatment, stretching or the like.

These terms can be defined with additional language in the remaining parts of the description. 20 Detailed Description of Currently Preferred Incorporations The present invention is directed to stretch laminates having an improved stretch, as well as to methods for making such stretched laminates. The invention is also directed to a machine that is capable of producing the stretchable laminates including both tapered and bonded laminates and vertical filament laminates.

Stretchable laminates can be incorporated into any suitable article, such as personal care garments, medical garments, and industrial workwear garments. Particularly, stretched laminates are suitable for use in diapers, underpants, swimwear, absorbent underpants, adult incontinence products, women's hygiene products, medical protective gowns, medical surgical suits, laces, gloves. , covers, face masks, lab coats, covers all and the like.

A number of elastomeric components are known to be used in the design and manufacture of such articles. For example, disposable absorbent articles are known to contain elasticized leg cuffs, elasticized containment flaps, elasticated waist portions, and elasticized holding appendages. The stretchable laminates of this invention can be applied to any suitable article to form such elasticized areas.

As shown in Figure 1, a stretchable laminate 20 of the invention includes a film layer 22 and an elastomeric open working layer 24 bonded to the film layer 22. The laminate 20 is stretched, and may be elastomeric. The laminate 20 may have different stretching properties in the machine direction than in the transverse direction. The arrows 32 and 34 in Figure 1 show the machine direction and the transverse direction, respectively.

The elastomeric open work 24 may be a plurality of elastic threads 26 (FIG. 1), an elastomeric mesh structure 28 (FIG. 2), an elastomer 30 printed in a pattern on the film layer 22 (FIG. 3) or a combination thereof. any of these forms of elastomers. It will be appreciated that the elastomeric open work 24 can be zoned, namely periodically arranged, not periodically or at various spacings, groupings or sizes, according to the desired effect from the stretchable laminate 20 and the use to which it is to be put.

As shown in Figure 1, for example, a group of yarns 26 in a laminate region 20 can be spaced and separated much more closely than another group of yarns 26, resulting in greater stress in the region in which the yarns 26 are more closely spaced. The wires 26 are essentially continuous in length. As another example, the elastic threads 26 can be unequally dimensioned with some threads 26 having a larger diameter and therefore a higher tension than others. Even though it has been mentioned herein as being of different diameter, it will be appreciated that the wires 26 need not be circular in cross section within the context of this invention. The wires 26 may have a circular cross section, but alternatively may have other geometries in cross section such as elliptical, rectangular, triangular or multiple lobes. In addition, the threads 26 of different size or composition can be interspersed with groups in regular or irregular patterns.

Similarly, the elastomeric open work 24 in the form of an elastomeric mesh structure 28 or printed elastomer 30 can be zoned, such as with a greater thickness or a higher basis weight in one or more regions of the laminate 20. Suitably, the Elastomeric mesh structure 28 has an overall length and width essentially equal to a length and width of the film layer 22. The printed elastomer 30 can be any suitable pattern, such as zig-zag strips or lines.

Suitable materials for use in preparing the elastomeric open work 24 include unprocessed polymer, a mixture of polymers which are also known as "compounds" as well as glutinized compounds or polymers. More specifically, the elastomeric open work 24 may include elastomeric diblock, triblock, tetrablock or other multi-block copolymers such as olefinic copolymers including ethylene-propylene-diene monomer (EPDM), styrene-isoprene-styrene (SIS) , styrene-butadiene-styrene (SBS), styrene-ethylene / butylene-styrene (SEBS), or styrene-ethylene / propylene-styrene (SEPS), or compounds of these elastomeric copolymers, which can be obtained from Kraton Polymers of Houston , Texas, under the trade designation Elastomeric resin KRATON®, or Dexco, a division of Exxon-Mobile under the trade designation VECTOR® (SIS polymers); polyurethanes, including those available from E.I. Du Pont de Nemours & Company, under the trade name LYCRA® Polyurethane, polyamides including polyether block amides available from Ato Chemical Company, under the trade name Amide Polyether Block PEBAX®, polyesters, such as those available from EI Du Pont de Nemours, Company, under the trade name HYTREL® polyester; polyisoprene; cross-linked polybutadiene; and metallocene-catalyzed or single-site polyolefins having a density of less than about 0.89 grams / cm 3, available from Dow Chemical Company, under the tradename AFFINITY®, or a similar material 24 available from ExxonMobile Corporation, under the trade name EXACT ™.

A number of other block copolymers and compounds of these copolymers can also be used to prepare the elastomeric open work 24. Such block copolymers generally include an elastomeric middle block part B and a thermoplastic end block part A. The copolymers of The block can also be thermoplastic in the sense that they can be melted, formed, and resolidified several times with little or no change in physical properties (assuming a minimum of oxidative degradation). Alternatively, the elastomeric open work 24 can be made from a polymer that is not thermally processable, such as LYCRA® spandex, available from E.I. Du Pont de Nemours Company, or a natural rubber crisscrossed in film or fiber form. Thermosetting polymers and polymers such as spandex, unlike thermoplastic polymers, once crosslinked can not be thermally processed, but can be obtained on a spool or other form and can be stretched and applied as threads in the same way as thermoplastic polymers.

The end block portion A may include a poly (vinylarene), such as polystyrene. The middle block portion B may include an essentially amorphous polyolefin such as polyisoprene, ethylene / propylene polymers, ethylene / butylene polymers, polybutadiene, and the like or mixtures thereof.

Suitable block copolymers can include at least two end block parts essentially of polystyrene and at least one middle block part of essentially ethylene / butylene. A commercially available example of such a linear block copolymer is available from the Polymers mouse under the trade designation elastomeric resin KRATON® G1657. The suitable elastomeric resin is KRATON® G2760.

The film layer 22 is suitably stretchable, and can also be elastomeric. In certain embodiments, the film layer 22 can be tapered for an improved cross direction stretch. The film layer 22 may also be capable of breathing so that the film layer 22 is impervious to the liquid but is still transmissible from the water vapor. The film layer 22 can be filled with calcium carbonate or other suitable filler to provide improved breathing capacity with stretching. Alternatively, the film layer 22 may be a monolithic film having a basis weight of about 8 grams per square meter or lower, or about 6 to 100 grams per square meter.

Because the film layer 22 is attached to the elastomeric open work 24, the film layer 22 can be formulated to satisfy a sufficient level of ability to breathe and stretch without an additional load of being elastic, thus essentially decoupling the elastic and breathing capacity requirements for the film layer 22.

In general, the film layer 22 may be made of any suitable film-forming mixture or resins. For example, the film layer 22 can be made into an elastomeric film, foamed elastomers, any of the materials of which the elastomeric open work 24 can be made. The film layer 22 may also be a multilayer material in the sense that it may include two or more individual coherent fabrics or films. Additionally, the film layer 22 may be a multilayer material in which one or more of the layers contains a mixture of elastic or stretchable particles or fibers.

The cross-machine direction stretch of the film layer 22 can be improved by giving the formed film layer 22 a stretch in the transverse direction before laminating the film layer 22 to the elastomeric open work 24. Stretch in the transverse direction it can be carried out using a frame frame, shaved rolls or any other technique known to those skilled in the art. Another suitable method for having a stretch in the transverse direction of the film layer 22 is to use a blown film process which produces a layer of film 22 with stretching properties or stretchable in the transverse direction. Alternatively, the film layer 22 can be stretched in the machine direction and thus tapered, prior to lamination to the elastomeric open work 24. By improving the stretching of the film layer 22, the resulting laminate 20 can be a Biaxial stretched laminate that stretches in both the machine direction and the transverse direction.

In certain embodiments, the film layer 22 may include an elastomeric adhesive film. Hot-melt, suitable elastomeric pressure-sensitive adhesives of which the elastomeric adhesive film can be made include elastomeric polymers, glutinizing resins, plasticizers, oils and antioxidants. An example of a suitable elastomeric adhesive film can be made up to 35% by weight of BICOLITE S115 and 65% by weight of KRATON G2760. The hot melt pressure sensitive adhesive elastomeric can be applied to a cooling roller or similar device in the form of a sheet or tape. The sheet or tape is then stretched minimally and thinned to form the film layer 22. The elastomeric adhesive film is capable not only of introducing a degree of elasticity into the stretchable laminate 20 but is also capable of providing a construction adhesive function. That is, the elastomeric adhesive film adheres itself to the elastomeric open work 24 and / or other components with which the elastomeric adhesive film is brought into contact.

A particular formula of the elastomeric adhesive film includes a base polymer and a glutinizing resin. The composition may also include additional additives. The choice of polymer and glutinizer is important, as is the ratio of the polymer or copolymers to glutinizer. Another important consideration is the ratio of additives to glutinizing.

The base polymer suitably has a styrene contact of between about 15% and about 45% or between about 18% and about 30% by weight of the base polymer. The base polymer can achieve the styrene content either by mixing different polymers having different levels of styrene comonomer or by including a single base polymer having a desired styrene comonomer level. Generally, the higher the level of styrene comonomer, the greater the tension.

The base polymer may include a polystyrene-polyethylene-polystyrene (SPS) block copolymer, styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, as well as any combinations thereof. . An example of a SEPSEP copolymer compound is available from the Polymers mouse of Houston, Texas, under the trade designation KRATON® G2760. An example of a suitable SIS polymer is available from Dexco, a division of ExxonMobil under the trade designation VECTOR®. Suitably, the elastomeric adhesive film composition includes the base polymer in an amount of between about 30% and about 65% by weight of the composition.

The glutinizer may include petroleum distillate hydrocarbons, rosin, rosin esters, polyterpenes derived from wood, polyterpenes derived from synthetic chemicals, as well as combinations of any of these. A key element of the elastomeric adhesive film composition is a glutinizer. An example of a suitable glutinizer is available from Hercules Inc. of Wilmington, Delaware, under the trade designation VICOLITE® S115. Suitably, the composition includes the glutinizer in an amount of between about 30% and about 70% by weight of the composition.

Other additives may also be included in the elastomeric adhesive film composition as well. In addition, of the adhesion provided by the glutinizer, various additives can provide instant surface tackiness and pressure sensitive characteristics as well as a reduced melt viscosity. An example of a particularly suitable softening point additive is the VICOLITE® S25 glutinizer, available from Hercules Inc. which has a softening point in a range of about 25 ° C, or paraffin wax having a melting point. around 65 ° C can also be used.

Additionally, an antioxidant may be included in the elastomeric adhesive film composition, suitably in an amount of between about 0.1% and about 1.0% by weight of the composition. An example of a suitable antioxidant is available from Ciba Special Chemicals, under the trade designation IRGANOX® 1010.

The film layer 22 suitably has a thickness of about 0.025 millimeters to about 1.27 millimeters alternately from about 0.025 millimeters to about 0.25 millimeters.

As shown in Figure 4, the stretch laminate 20 may include multiple film layers, such as a second layer of film 36 laminated to the film layer 22 with the elastomeric open working layer 24 placed between the two layers of film 22. and 36. The second film layer 36 may be formed of the same material as the film layer 22, or it may be formed of any other suitable film material, and may be either continuous or discontinuous such as in the form of a plurality. of movie tapes. In certain embodiments, wherein the second film layer 36 is in the form of a plurality of film tapes, the film tapes can be zoned to create areas of higher or lower tension, for example.

If the two film layers 22 and 36 do not completely marry, or are joined to one another across the entire contact surface, the separations are formed which can serve as a built-in spacer layer. Alternatively, the film layers 22 and 36 can be treated with a humectant such as a silica gel or a desiccant such as calcium chloride, or a vapor absorbing coating of water or particles of super absorbent material, on the contacting surfaces. with the elastomeric open work 24 to minimize the transfer of water vapor through the laminate 20, potentially reducing or eliminating moisture concerns at high breathing capacity levels.

As shown in Figure 4, the stretch laminate 20 may also include one or more cover layers 38 and 40 bonded to the first and / or second film layers 22 and 36. Examples of suitable cover layers 38 and 40 they include films, non-woven fabrics, such as spunbonded fabrics and meltblown fabrics, or any combination thereof. In one embodiment, the coating layer 38 may be a multilayer material having, for example, at least one layer of a spunbonded fabric attached to at least one layer of the melt blown fabric or other suitable material. As another example, a coating layer 38 can be a multilayer material having a first layer of spin-linked polypropylene having a basis weight of from about 0.2 to about 8 ounces per square yard (osy), a layer meltblown polypropylene having a basis weight of from about 0.2 to about 4 ounces per square yard, and a second layer of polypropylene bonded with yarn having a basis weight of about 0.2 to about 8 ounces per square yard . Alternatively, the coating layer 38 can be a single material layer such as, for example, a spunbonded fabric having a basis weight of from about 0.2 to about 10 ounces per square yard or a meltblown fabric that It has a basis weight of from about 0.2 to about 8 ounces per square yard. Conventional bonding techniques, such as thermal bonding, hydroentangling, and ultrasonic bonding can be used to form the coating layer 38, as well as to join any of the lamination components 20 to one another.

When two or more of the coating layers 38 and 40 are present in the laminate 20, the coating layers 38 and 40 may be the same as others, or the coating layers 38 and 40 may differ. For exampleEach coating layer 38 and 40 can be made of the same type or of different types of filaments, with the same or different types of bonding patterns such as a bonded pattern that provides strength and another bonded pattern that provides softness. In addition, the coating layers 38 and 40 may differ in terms of different polymers, different base weights, different fiber size, fiber type, shape and the like. Optionally, the different widths of the coating layers 38 and 40 can be formed and narrowed by different amounts to finish with the same width of the coating layers 38 and 40. The highly tapered coating layer will generally soften more and be weaker. than the coating layer that is not narrowed to a large extent.

In one embodiment, for example illustrated in Figure 5, the laminate 20 may include an expandable film layer 22, filled with calcium carbonate or other suitable filler to provide ability to breathe with the stretch. The laminate 20 may also include an inherently stretchable or elastic nonwoven covering layer 38, such as a fabric bonded with bicomponent yarn, or adhesively laminated layers of such materials. Between the film layer 22 and the coating layer nonwoven 38 is an extruded layer of an open elastomeric work 24 in the 34 form of a structure of elastomeric mesh 28 which may be an elastomer and can also provide a stretch pressed due to the structure. This laminate 20 has the advantage of using a layer of film 22 that can be formulated to meet the breathing ability objectives without the additional burden of being elastic by essentially decoupling the elastic and breathability requirements for the film layer 22. The elastomeric mesh structure 28 is essentially an extruded layer so that there is a flexibility in the choice of resin, mesh structure and the like.

In another embodiment, illustrated in Figure 6 for example, the laminate 20 may include a film layer that can extend in the transverse direction and breathable 22, or a very low monolithic film layer 22, with a open elastomeric working layer 24 in the form of an elastomer 30 printed on a surface of the film layer 22 in strips or bars. The printed elastomer 30 provides sufficient stretch and recovery. The film layer 22 is then laminated to a layer of elastic and / or inherently stretchable film 36 with the printed elastomer 30 placed between the two film layers 22 and 36.

In yet another embodiment, illustrated in Figure 7 for example, the laminate 20 can include two layers of outer film 22 and 36 that are breathable and that are stretchable or elastic, and an elastomeric open working layer 24 in the form elastic threads 26 between the two layers of outer film 22 and 36. Each of the film layers 22 and 36 and the elastomeric open-work 24 are extruded through a matrix, with elastomeric open work 24 extruded through a matrix designed to create elastomeric strips or ribbons. The coating layers 38, 40 are either adhesively or thermally bonded to the outer film layers 22 and 36.

Laminates that can be stretched 20 are particularly useful for providing stretch characteristics in absorbent personal care garments 78, as shown in Figure 8. More specifically, as shown in Figure 8, the laminates that can be stretched 20 are particularly suitable for use to provide outer covers 72 with a capacity for breathing, extension in the transverse direction, and possibly humidity control. Additionally, the stretchable laminates 20 are also particularly suitable for use on the side panels 74, the ears 76, the waistbands 78, and / or the leg elastics 80 in such garments.

Figure 9 illustrates a method and apparatus for making a laminate that can be stretched 82 as described above. As shown, a film 84 is extruded from a first film matrix 88, suitably on a first roller 90. The first roller 90 can be temperature adjustable, such as a heating roller or a cooling roller. The film 84 is stretched between the first roller 90 and a second roller 92 as the film 84 is brought to the pressure point 101. An elastomeric open work layer 86, as described above, can be formed and stretched as it is worn. 86 elastomeric open work on film 84.

The method may also include thinning, shrinking, and / or heat treating the film 84. Said film 84 may also be stretched a second time, particularly after cooling. The elastomeric open work 86 can also be heat treated and / or stretched a second time. Alternatively, the film tapes rather than the elastomeric open work 86 can be stretched and adhered to the stretched film 84. As another alternative, both film tapes 94 and the elastomeric open work 86 can be adhered to the film 84. Stretch steps create thinner films 84 or a thinner elastomeric open work 86, resulting in laminates 82 that are thinner in general.

Optionally, a second film 94 may be set through a second film die 96 on an open elastomeric work 86 on top of the first film 84 as the first film is stretched, thereby encapsulating the elastomeric open work 86 between the film layers 84 and 94. The first film 84 and / or the second film 94 may instead be a foam or a foamed elastomer, which is foamed in line. The polyurethane film does not settle completely immediately and therefore foam easily. Alternatively, the first film 84 and / or the second film 94 may be in the form of film tapes, as described above. Like the first film 84, the second film 94 can also be thinned, narrowed, and / or heat treated.

Additionally, one or more coating layers 98 and 99 may be bonded to the film 84 and / or 94, and / or the elastomeric open work 86. The coating layer or layers may include any of the coating layer materials previously discussed. , such as a narrowed material. Various subsequent treatments, such as grooved roll treatment, which alter the mechanical properties of coating layers 98 and 99, are also suitable for use. The coating layers 98 and 99 can also be made in place rather than unrolling from previously made rolls of material.

The laminate 82 resulting from this incorporation of the method may have a different stretch in the machine direction than in the transverse direction. In addition, the laminates can be "unified", with different elastic properties along the length and / or the width of the laminate, which can be created through the zoning of the first film 84, of the elastomeric open work 86, and / or of the second film 94. Additionally, the adhesive 100 used to join the coating layers 98, 99 to the film 84 and 94 can be zoned to create additional functionality.

The film 84 and 94 in this method can be any of suitable film types described in detail above, including elastomeric films, foamed elastomers, filled films, and elastomeric adhesive films. Also, the elastomeric open work 86 may be in the form of elastic yarns, in an elastomeric mesh structure or any other suitable form as described in detail above. An illustration of the apparatus suitable for creating an elastomeric mesh structure is provided in Figure 10. More particularly, the apparatus includes a pattern roller 102 on which the elastomer is extruded from a film matrix 104.

Most laminates currently have a layer of elastomeric material or more than two that are integrated with the extrusion and are not separately handled green before they are integrated together. As used herein, the term "green" refers to a material that has never been rolled or otherwise placed in storage. For example, the laminate is produced within 5 minutes, 3 minutes, 1 minute, 30 seconds, 15 seconds, or 5 seconds from the production of the "green" material. The ability to handle film 84 and 94 and open elastomeric work 86 separately, but in the same process, provides benefits to form new elastic structures beyond those currently practiced.

By fixing the elastomeric open work 86 on the green film 84 the occurrence of a wire or mesh slip is greatly reduced. Since the film 84 is pressure sensitive and sticky when the elastomeric open work 86 is applied to the film 84, the need for adhesive between the film 84 and the elastomeric open work 86 is eliminated and in addition, yarn slip is prevented. or mesh. Additionally, the elastomeric open work 86 may be at least partially imbibed or encapsulated by the green film layer 84.

Another advantage of this method is that the first and second rollers 90 and 92, which can serve as setting and hardening rollers, respectively, can be run independently of one another in terms of temperature and speed, which means that the film can be tempered or cooled as desired to introduce 40 properties such as latency, elastic inactivity, or even improve the settling of the elastomer for more immediate elastic properties.

The resulting laminates 82 can have a multi-phase stretch profile. As used herein, the term "multi-phase stretch profile" refers to a laminate or other composite that demonstrates a change in the extension modulus, such as a tension-against-elongation profile of the laminate showing three or more different stretching phases corresponding to at least three different layers having different elongation-counter-tension profiles within the laminate. Laminates having a multi-phase stretch profile have unique stretching characteristics, such as multiple top-stretch values at certain tensioning forces.

For example, Figure 11 is an exemplary elongation-counter-tension profile of a laminate having a multi-phase stretch profile in the machine direction. The particular laminate having the multi-phase stretch profile illustrated in FIG. 11 may include a film layer 84 that is stretched by about 200% in the machine direction and an elastomeric open work layer 86 that is stretched by about 100% in the machine direction when the 41 film layer 84 and the elastomeric open work 86 are joined together. One or more coatings 98 and 99 may then be attached to the stretched film layer 84 and the stretched elastomeric open work 86, both of which are still stretched by their respective amounts of 200% and 100% in the machine direction. After passing through the pressure point 101, the laminate 82 can be relaxed. With loosening, the coatings 98 and 99 will retract by about 200% due to the shrinkage of the stretched film layer 8. Similarly, the elastomeric open work 86 will retract by about 100% due to the loosening of the stretched film layer 84. FIG. 11b is an exemplary elongation-counter-tension profile of the film layer 84 within the laminate. The film layer 84 initially exhibits an increase in tension with the increase in elongation, but the tension is leveled at about 100% elongation. Figure 5 is an exemplary elongation-counter-tension profile of an elastomeric open work 86 within the laminate. Because the elastomeric open work 86 is picked up due to 100% retraction, essentially no tension occurs during the first 100% elongation; however, once the elastomeric open work 86 is not picked up (at 100% elongation), the tension increases with the increase in elongation and is leveled at around 200% elongation. Figure lid is an example elongation-counter-tension profile of coatings 98 and 99 within the laminate. Because coatings 98 and 99 are 42 folded due to 200% retraction, essentially no tension occurs during the first 200% elongation; however, once coatings 98 and 99 are deployed (at 200% elongation), tension increases at a rapid rate. In Figure 10 it can be seen that the laminate 82 as a whole exhibits the three phases of the three different types of layers separately. The resulting laminate 82 therefore has a machine direction stretch of about 200%. If the coatings 98 and 99 are stretched, the laminate 82 may also have a stretch in the transverse direction.

An exemplary elongation-counter-tension profile of another laminate having a multi-phase stretch profile in the transverse direction is illustrated in Figure 12a. The particular laminate having the multi-phase stretch profile illustrated in Figure 12a may include a film layer 84 (or an elastomeric open work layer 86) bonded to a first coating 98 that is narrowed by about 25% and a second coating 99 which is narrowed by about 40%. The elongation of the resulting laminate 82 in the transverse direction will result in the elongation-counter-tension profile of Figure 12a. Figure 12b is an exemplary elongation-counter-tension profile of the film layer 84 within the laminate. The film layer 84 initially exhibits an increase in tension with the increase in elongation, but the tension is leveled at minus 43 of 33% elongation. Figure 12c is an exemplary elongation-counter-tension profile of the first coating 98 within the laminate. Because the first coating 98 is narrowed by about 25%, the first coating 98 reaches its non-tapered width when the laminate is stretched by about 33%, at which point the tension increases dramatically. Figure 12d is an exemplary elongation-counter-tension profile of the second coating 99 within the laminate. Because the second coating 99 is narrowed by about 40%, the second coating 98 reaches its non-tapered width when the laminate is stretched by about 67%, at which point the tension drastically increases. In Figure 12a it can be seen that the laminate 82 as a whole exhibits the three phases of the three different types of layer separately. The resultant laminate 82 therefore has a stretch in the transverse direction of about 67%.

An exemplary elongation-counter-tension profile of yet another laminate having a multi-phase stretch profile in the transverse direction is illustrated in Figure 13a. The particular laminate having the multi-phase stretch profile illustrated in Figure 13a may include a film layer 84 (or an elastomeric open work layer 86) attached to a first coating 98 of a relatively weak material that is tapered around of 25% and a second coating 99 44 of a stronger material that is narrowed by about 40%. The elongation of the resulting laminate 82 in the transverse direction will result in the elongation-counter-tension profile of Figure 13a. Figure 13b is an exemplary elongation-counter-tension profile of the film layer 84 within the laminate. The film layer 84 initially exhibits an increase in tension with increasing elongation but the tension is leveled to less than 33% elongation. Figure 13c is an exemplary elongation-counter-tension profile of the first coating 98 within the laminate. Because the first coating 98 is narrowed by about 25%, the first coating 98 reaches its non-tapered width when the laminate is stretched by about 33%, at which point the tension increases drastically; however, when the tension exceeds the strength of the material, such as at about 5 pounds per square inch, the first coating 98 tears or otherwise fails. Figure 13d is an exemplary elongation-counter-tension profile of the second coating 99 within the laminate. Because the second coating 99 is narrowed by about 40%, the second coating 98 reaches its non-tapered width when the laminate is stretched by about 67%, at which point the tension increases drastically. Since the second coating 99 is stronger than the first coating 98, the second coating 99 allows the laminate to withstand a tension greater than that which the first coating 98 alone can withstand. In Figure 13a it can be seen that the laminate 82 as a whole exhibits the three phases of the three different types of layers separately. In using, the failure of the first coating 98 to about 45% stretch in the transverse direction can serve as a warning sign to a user that the laminate is approaching the peak voltage load, thus signaling to the user that it should not be applied an additional tension to the laminate in order to avoid the failure of the laminate. Despite the failure of the first coating 98, the laminate may be capable of stretching 67% in the transverse direction without resulting in the failure of the second coating 99.

In another embodiment of the invention, a machine 105 capable of carrying out both the vertical filament lamination (VFL) processes and the narrow and joined laminate (NBL) processes can be used to carry out any of the methods of the invention. The machine 105 has unique characteristics that allow it to process the materials with machine direction, cross direction and biaxial stretch.

Both NBL and VFL laminates may include similar coating materials, such as spunbonded fabrics or other suitable non-woven fabrics, with the coating materials in the NBL being narrow-stretched. In addition, the coating materials in both NBL and VFL processes can be adhesively or thermally 46 attached to an elastic core. The elastic core may be an elastomeric open work layer as described above. More particularly, the elastic core can be either a set film for NBL or filament yarns for VFL, for example.

An embodiment of the machine combination 105 is illustrated in Figure 14. The machine 105 is based on a conventional VFL platform including a filament matrix 106 for extruding the elastic core 108 from an extruder 124 onto a first forming roll or roller 110. , and a second roller 112 which passes the elastic core 108 down to a pressure point 114 with the coatings 116 and 117 applied to the elastic core 108 before passing through the pressure point 114 and on a reel 118. One or both of the rollers 110 and 112 may be a chill roll, one or more adhesive application zones 126 may be present in the machine upstream of the pressure point 114. Downstream of the pressure point 114, such as in the space between the holding point 114 and the window 118 may have a relaxation zone 128 having negligible tension.

Additional equipment is added to the VFL platform to allow the production of NBL. The additional equipment includes one or more furnaces 120 and 121 for the narrowing of the coatings 116, 117 and the film die 122 mounted 47 on one side of the filament die 106. Similar productions of NBL and VFL, based on weight Elastic base and fabric width, allow the two processes to be combined in the machine while using the same extruder 124 and pellet handling systems, or alternatively, a conventional hot melting equipment, such as a tank melted or an extruder. As an alternative, the film matrix 122 and the filament matrix 106 can be fed from different extruders.

Alternatively, the machine 105 may be set so that one of the coatings 116 is guided over the first forming roller 110 and the elastic core 108 is extruded onto the coating 116. This embodiment of the machine is illustrated in FIG. 15.

As yet another embodiment, rather than being unrolled from a roll, one. or more of the coatings 116 and 117 can be formed simultaneously through the additional extruders.

The elements of each incorporation discussed here are interchangeable with or can be combined with the other incorporations.

It will be appreciated that the details of the above embodiments given for purposes of illustration, should not be considered as limiting the scope of the invention. Although only a few example embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without departing materially from the teachings and novel advantages of this invention. Therefore, all such modifications are intended to be included within the scope of the invention, which is defined in the appended claims and in all equivalents thereof. Furthermore, it is recognized that many incorporations can be conceived which do not achieve all the advantages of some incorporations, particularly the preferred incorporations, but that the absence of a particular advantage should not be considered as necessarily implying that an incorporation is outside the scope of the present invention.

Claims (20)

49 CLAIMS

1. A stretchable laminate comprising: a first layer a second layer; Y an elastomeric layer bonded to the first and second layers; wherein the laminate has a multi-phase stretch profile.

2. The stretchable laminate as indicated in clause 1 characterized in that the laminate has a multiple phase stretching profile in at least one of a machine direction and a transverse direction.

3. The stretchable laminate as indicated in clause 1 characterized in that at least one of the first and second layers comprises at least one of the group consisting of elastomeric material, narrowed material, a non-woven fabric, a film, a fabric joined with spinning, a blown fabric with melting, and combinations thereof.

4. The stretchable laminate as indicated in clause 1 characterized in that the first and second layers are both narrow and the first layer is narrowed to a greater extent than the second layer.

5. The stretchable laminate as indicated in clause 1 characterized in that, the first layer can withstand a higher tension without failure than the second layer.

6. The stretchable laminate as indicated in clause 1 characterized in that, the elastomeric layer comprises at least one of the group consisting of an elastomeric adhesive film, a plurality of elastic yarns, a plurality zoned of elastic yarns, a mesh structure elastomer, and an elastomer printed in a pattern on the first layer.

7. The stretchable laminate as indicated in clause 1 characterized in that, the laminate is incorporated in a garment in at least one of the group consisting of side panels, ears, waistbands, leg elastics or other covers and combinations thereof .

8. A method for making a stretch laminate, comprising the steps of: extruding a first film from a first die; stretch the first movie; forming and stretching an elastomeric open work layer; bring the elastomeric open work stretched over the first film while the first film is stretched; pass the first film and open elastomeric work through a pressure point.

9. The method as claimed in clause 8, characterized in that it comprises stretching the first film and elastomeric open work to different extensions.

10. The method as claimed in clause 8 characterized in that the first film comprises at least one of the group consisting of a plurality of film tapes, a foamed elastomer, an elastomeric adhesive film and combinations thereof.

11. The method as claimed in clause 8, characterized in that the elastomeric open work comprises at least one of the group consisting of a plurality of elastic threads, an elastomeric mesh structure, and an elastomer printed in a pattern. on a substrate.

12. The method as claimed in clause 8 further characterized in that it comprises the steps of passing the first film from a first roll onto a second roll, and bringing a second film from the second die onto the second roll over the top of the second roll. the first film and the elastomeric open work.

13. The method as claimed in clause 8 or 12 further characterized in that it comprises the step of laminating at least one coating layer to a surface of at least one of the first film, the second film and the open work elastomeric

14. The method as claimed in clause 13 further characterized in that it comprises the step of tightening at least one covering layer.

15. The method as claimed in clause 13 further characterized in that it comprises the step of tightening the first and second coating layers, 53 tapering the first coating layer to a greater extent than the second coating layer, and laminating the layers. of first and second coating narrowed to the first film and open elastomeric work.

16. The method as claimed in clause 8 or 12 further characterized in that it comprises the step of zoning at least one of the first film, the second film and the elastomeric open work.

17. A machine capable of producing stretching materials in the direction of the machine, in the transverse direction, and biaxial comprising: at least one extruder; at least one filament matrix attached to at least one extruder; at least one film matrix attached to at least one extruder; Y at least one pressure point downstream of at least one of the filament matrix and the film matrix.

18. The machine as claimed in clause 17 further characterized in that it comprises at least one furnace upstream of the pressure point, at least one adhesive application area upstream of the pressure point, and / or a zone of relaxation down from the pressure point.

19. The machine as claimed in clause 17 further characterized in that it comprises a first downward roller of at least one of at least a first film matrix and the at least one filament matrix, and a second roller towards down the first roller.

20. The machine as claimed in clause 19 characterized in that at least one of the first roller and the second roller comprise a cooling roller.