KR950006867B1 - Gathered nonwoven elastic web - Google Patents

Abstract

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Description

Method of Making Gathered Nonwoven Elastic Web

1 is a schematic view showing a form for carrying out one of the embodiments of the present invention.

2 is a schematic diagram showing a form for carrying out one of the other methods of the present invention.

3 is a schematic view showing a form for carrying out a method of the present invention in which a gathered web is separated from an elastic web.

4 is a schematic view showing a form for carrying out another method of the present invention in which a gathered web is separated from an elastic web.

5 is a plan view of an unbiased, retracted, stretchable and extendable forming screen that can be used as the forming screen in the process shown in FIG.

6 is a plan view of the stretchable and retractable forming screen of FIG. 5 in a deflected, stretched arrangement.

7 is a schematic view showing a form for carrying out another method of the present invention in which two gathered webs are separated from an elastic web.

* Explanation of symbols for main parts of the drawings

10 melt blown fine fiber 12 conventional melt blowing die

14: porous connection screen 18,20: roller

22: adhesive fibrous nonwoven elastic web 24, 28: nip or gap

26: nip roller 30, 40: roller

32: Nip roller 36: Second porous porous screen

42: nip or gap 44: nip roller

46: melt blown fine fiber 48: conventional melt blowing die

50: adhesive fibrous nonwoven elastic web 52: hybrid nonwoven elastic web

54: nip or gap 56, 58: nip roller

60: supply roller 62,68: nip

70,72: Nip Roller 74,76: Storage Roll

80,82,88,90: Roller 84: 3rd porous focused screen

86 nip or gap 94 conventional melt blowing die

96: Gatherable second nonwoven web 98: Melt blowing fine fibers

100: hybrid web 102: nip or gap

104,106: nip roller 110: stretchable porous focused screen

114: wire mesh screen 116: spring

118: lateral wire 120,122: roller

130: nip 132,134: nip roller

136: band 138: melt blown fine fibers

140: conventional melt blowing die 142: nip

144: Nip Roller 146: Band

148: supply roller 150: nip

152,154: Nip Roller 158,160: Nip Roller

162,164: storage roll 168,170: nip roller

172: storage roller

The present invention relates to a hybrid nonwoven elastic web comprising a nonwoven elastic web bonded to a nonwoven gathered web and a method of forming the hybrid nonwoven elastic web. The present invention also relates to a method of forming a gathered nonwoven web exhibiting elastic properties by separating the gathered web from the nonwoven elastic web after performing gathering by shrinkage of the elastic web.

In the field of diaper manufacturing, (1) the entire surface of the diaper is elastic to provide tight and comfortable wearability, (2) water repellent to retain fluid material within the boundaries of the diaper, and (3) vapor through the diaper material. It has been desired to provide a diaper sheath that is breathable to exchange the pressure, (4) soft to improve comfort, and (5) low in manufacturing cost, which can be economically supplied to consumers.

Unfortunately, known hybrid nonwoven materials that have been marketed so far lack one or more of the above characteristics. In addition, such hybrid elastic nonwoven materials have not been produced using the novel and economical method of the present invention.

For example, Wade US Pat. No. 2,957,512 describes a method of making an elastic hybrid sheet material in which a crepe or pleated flexible sheet material is adhered to, for example, a meltblown elastomer. . In columns 5 and 39-48 of this patent, when the fibrous web of elastomeric material is stretched and adhered to the pleated web at points or sites at regular intervals, the hybrid body is shown in FIG. 7 when the fibrous elastomeric web is relaxed. It is described as being the structure shown.

Another method of forming a hybrid elastic fabric is described by Pufahl in US Pat. Nos. 3,316, 136. A suitable method of making this fabric is by using an adhesive, which is first applied to an elastic backing material in a predetermined pattern, and then stretched in the extended state. While the elastic material is in the extended and stretched state, the fabric to be placed thereon is placed in contact with it and secured to the elastic material and the pressing mechanism for a time sufficient to bond the two layers. Thereafter, after the applied adhesive is dried, the tension on the elastic backing material is relaxed so that the underlying fabric is gathered in the area contoured by the adhesive.

Example 56 of US Pat. No. 3,485,706 to Evans describes a method of making a non-woven, multilevel patterned structure that is elastically stretchable in one direction initially from a layered material. This structure consists of two webs of polyester staple fibers with a web with spandex yarn therebetween. These webs are joined together using a hydraulic jet that entangles the fibers of one web with the fibers of an adjacent web. During the entanglement phase, the spandex yarn is stretched 200%.

Brown, US Pat. No. 3,673,026, describes a process for making laminate fabrics, in particular controlled bulk nonwoven laminate fabrics. In this method, the separating webs of a nonwoven material, such as crepe tissue or bonded synthetic fibers, are elastically stretched to different elongations while, on the other hand, laminated together by bonding them together in differential stretches. Thereafter, the bonded webs are relaxed so that a different degree of shrinkage is obtained for each web, separating the webs into non-bonded areas and controlled bulk in the laminate. This patent claims to include differential stretches where only one web is actually stretched and the other web is kept loose or similar.

Wideman, US Pat. No. 3,687,797, describes a process for producing a resilient cellulose cotton product obtained by laminating a low cellulose wadding web with a pre-extended polyurethane foam web. The method involves adhering the cotton web to one of the webs in a desired pattern and then laminating with a pre-stretched polyurethane foam web. The foam web remains stretched while the cotton web is laminated with the polyurethane foam web. After laminating the two webs, the tension on the pre-stretched polyurethane foam web is relieved to cause the foam web to shrink. The adhesive holds the intermediate and the foam together while bulking at the portion between the adhesive zones. The stress remaining in the product after shrinkage can be further alleviated by wetting.

Wideman's US Pat. No. 3,842,832 relates to disposable kidney products, such as bandages, and to methods of making the products. This product is made by passing a roller through a nonwoven material which is oriented in the longitudinal direction such that the adhesive is applied to one surface of the nonwoven material. At the same time, the polyurethane web is heated, stretched longitudinally and bonded to the nonwoven material. Thereafter, the second nonwoven material is adhered to the polyurethane web to the other surface to form a laminate of the unstretched outer nonwoven layer bonded by the stretched inner polyurethane core and the adhesive. The laminate is then passed through a humidifier to loosen the bond between the nonwoven outer layer and the adhesive that bonds the outer layer to the stretched polyurethane core layer. This causes the stretched polyurethane layer to substantially return to its initial length, causing the outer nonwoven layers to bend or corrugate to form wrinkles.

Nedza, US Pat. No. 4,104,170, describes a liquid filter made of polypropylene in an improved stretch state. The production of the polypropylene portion forms a spunbond underlayer of continuous propylene fibers, which are then attached in random form to the underlying itself. Subsequently, a cover layer of short propylene fibers is deposited on the upper layer, for example by meltblowing the cover layer to the lower stretched sheet.

Methods of making elastic fabric structures comprising fibers of synthetic, organic, relatively elastomeric polymers and fibers of synthetic, organic, stretchable but relatively inelastic polymers are described in Sisson, US Pat. No. 4,209,563. This method includes relatively elastic fibers and extensible but relatively inelastic fibers for randomly laying down a good spray on a porous forming surface of an unbonded web with random fiber crossings. The step of conveying is included. Thereafter, at least a portion of the fiber crossing is bonded to form a tightly bonded fabric web, the fabric web is stretched to stretch a portion of the fiber in at least one direction, and then relaxed to shrink the web by a relatively elastic fiber. Provides looping and bunching of stretchable but relatively inelastic fibers. The transfer of the fibers to the porous forming surface is actively controlled, which contrasts against the use of airflow to transport the fibers in column 7, lines 19-33 of the patent. In addition, it is described that filament bonding for producing the contact fabric in column 9, line 44 or less of this patent may use an embossing pattern or mildly heated roll nips.

US Patent No. 4,296,163 to Emi et al. Discloses (A) a plate network consisting of fibers of synthetic elastomeric polymers (individual fibers of which are randomly connected to one another in a random manner to form a plurality of network structures of different sizes and shapes. The network structure is stretched 10% in a direction perpendicular to each other arbitrarily selected on the plane of the network structure, and has a recovery rate of at least 70%) and (B) a mat or web of short or long fibers. A fibrous hybrid with a coalesced assembly of a plate-like fibrous structure, which at least optionally has a recovery rate of less than 50% after stretching 10% in one direction, is described. The patent describes that elastic hybrids are suitable as various coating base materials and industrial materials such as filter cloths, absorbents and heat insulating materials. Methods of forming hybrids are described below in column 6, line 64 of this patent, which include spun bouding (see columns 9, lines 15-41).

Des Marais, US Pat. No. 4,323,534, describes an extrusion process for thermoplastic resin compositions for textile fibers having excellent strength and good modulus of elasticity. Meltblowing of a mixed resin consisting of 79.13% KRATON G-1652, 19.78% stearic acid, 0.98% titanium dioxide and 0.1% Irganox1010 homeotropic agent in the "Fiber-Forming" sub column of this patent. It is. Individual fibers are described as extruded from a meltblowing die.

Jones, US Pat. No. 4,355,425, describes a panty with a built-in elastic system and a method of assembling the panty to minimize gathering and provide comfortable and suitable wear. This patent also describes the material as being very suitable as a material panty fabric material made of meltblown KRATON rubber. This patent also describes the manufacturing process of meltblown KRATON fabrics, which are outlined in FIG. 8 of this patent. Methods that appear to use KRATON G-1652 are discussed from column 4, line 67 of this patent.

Walhlquist, U.S. Patent No. 4,379,192, describes a method of forming a film and a fibrous web to form a non-permeable absorbent barrier fabric, wherein at least one of the meltblowing dies is formed on a pre-bonded web of continuous filaments. Melt blown discontinuous fibers having a small diameter as a mat. By forming a fine fiber mat directly on the continuous filament web pre-bonded to column 3, lines 35-40 of this patent, between the fine fibers and the continuous filament (the continuous filament attaches the fine fiber mat to the continuous filament web) A method of forming primary bonds is described.

Likyani's U. S. Patent No. 4,426, 420 describes a hydraulically entangled spunlace fabric of at least two types of staple fibers and a method of making the same, which is typically used as a staple fiber until heat treatment. Heat treating the elastomeric fibers gives the fabric improved elongation and elasticity. The method also includes potentially calculating the elastic fibers and relaxing the elastic fibers between the stretching and winding steps.

Romanek's US Pat. No. 4,446,189 describes a nonwoven fabric laminate, which is attached to the elastic layer by needle punching so that the nonwoven layer of the fabric drafts the elastic layer within its elastic limits. At least one layer of a permanently stretched nonwoven fabric. When the elastic layer is relaxed to return to its state substantially before drafting the elastic layer, the nonwoven layer is described as exhibiting increased bulk as a result of its simultaneous relaxation action. This patent also describes that nonwoven fabric laminates can be used to make garments with increased mobility freedom.

The abstract of Japanese Patent Application No. 47-43150 describes a method for producing a nonwoven fabric having high strength, which (a) shortens or stretches a sheet or film made of a mixture of incompatible polymers. and (b) laminate or layer of foamed polymer layer of the foam, (c) the laminate is elongated at right angles to the orientation direction of the substrate, and (d) is stretched in the orientation direction of the substrate. Suitable polymers include polyamides, linear polyesters and polyolefins. The top layer is described as being suitable for polypropylene foam.

Shell Chemical Company, entitled “KRATON Thermoplastic Rubber,” describes the thermoplastic KRATON material in this booklet. This booklet is the code designated as “SC: 1983-83, United States Edition, 7/83 SM”.

While these documents may describe products or methods that exhibit only some of the properties or method steps of the present invention, none of them describe or imply a process claimed in the present invention or a product produced by these processes. none.

As used interchangeably herein, the terms “elastic” or “elastomeric” are elongated when applying a biasing force, and the deflected length (which is at least about 125%, ie Refers to a material which can be stretched to about 1 and a quarter times the length of the relaxed, unbiased length, and at least about 40% of its elongation is returned when relaxing the stretch and extension forces. A hypothetical example that meets this definition of elastomeric material may be stretched to at least about 3.25 cm (1.25 inches), and stretched to about 3.25 cm (1.25 inches) and then relaxed to about 3.00 cm (1.15 inches) A sample of about 2.54 cm (1 inch) of material that is returned to length. Many elastic materials can be stretched by more than 25% of their relaxed length and, upon releasing the stretching and stretching forces of many of these elastic materials, they will return substantially to the initial relaxed length, It is generally suitable for the purposes of the present invention.

As used herein, the term "recover" refers to the contraction of the stretched material when the application of the biasing force is used to stretch the material and then the application of the biasing force is terminated. For example, if a relaxed, unbiased material having a length of about 2.54 cm (1 inch) was stretched to 50% elongation to a length of about 3.75 cm (1.5 inch), the material would be 150 of its relaxed length. Have an elongated length corresponding to%. When this exemplary stretchable material is retracted, i.e., returned to a length of about 2.8 cm (1.1 inches), after relaxing the deflection and stretching forces, the material returns to 80% of its elongation (about 0.4 cm). Will be.

As used herein, the term "nonelastic" or "nonelastomeric" refers to and includes any material that is not included in the term "elastic" or "elastic".

The term “meltblown microfibers” described herein has an average diameter of about 100 microns or less, preferably about 0.5 microns to about 50 microns, more preferably about 4 microns to about 40 microns, and the melted yarn or filament As an example, a molten thermoplastic material is a fine, typically circular, stream of high velocity gas (e.g. air) through a number of die tubules, which thins the filament of the molten thermoplastic material, reducing the diameter of the filament to the above range. It means a fiber having a small diameter manufactured by extrusion. Thereafter, the meltblown microfibers are carried by the high velocity airflow and deposited on the focusing surface to form a web of disorderly released meltblown microfibers. This method is described, for example, in Butin, US Pat. No. 3,849,241, which is incorporated by reference.

As used herein, the term “spunbond microfibers” has a diameter of 100 microns or less, preferably from about 19 to about 50 microns, more preferably from about 12 to about 30 microns, as a filament to fine the molten thermoplastic material. And a small diameter fiber prepared by extruding through a tubular tube of a plurality of waterproof holes, which is usually circular, and rapidly reducing the diameter of the extruded filament, for example, by drawing stretching or other known spunbonding mechanisms. The manufacture of spunbonded nonwoven webs is described in Appel US Pat. No. 4,340,563, which is incorporated by reference.

As used herein, a "nonwoven web" includes any web of material formed without the use of a textile weaving process that produces a structure of individual fibers interwoven in an iterative manner that can be identified. Specific examples of nonwoven webs include, but are not limited to, meltblown nonwoven webs, spunbond nonwoven webs, cracked films, microporous webs, or carded webs of staple fibers. Such nonwoven webs have an average basis weight of about 300 g per square meter. Suitably the nonwoven web has an average basis weight of about 5 g to 100 g. More preferably, the nonwoven web has an average basis weight of about 10 g to about 75 g per square meter.

As used herein, the term “mainly... The term “consisting of” does not exclude the presence of additional materials that do not significantly affect the properties and properties of the elastomer. Examples of this kind of material include pigments, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, particulates and materials added to increase the processing capacity of the composition.

As used herein, “styrene-based moiety” refers to a monomer unit represented by the following structural formula.

Unless specifically described and defined or otherwise limited herein, “polymers” or “polymer resins” are not limited to these homopolymers or copolymers such as block copolymers, graft copolymers, Random copolymers and alternating copolymers, terpolymers and the like, or mixtures or modifications thereof. Also, unless otherwise limited, “polymer” or “polymer resin” includes all possible geometries of the material. These arrangements include, but are not limited to, isotactic symmetry, syndiotactic symmetry, and random symmetry.

It is therefore a general object of the present invention to provide a new method of forming a hybrid nonwoven elastic web of nonwoven elastic webs to which a fibrous nonwoven gathered web is bonded.

Another general object of the present invention is to provide a new method for producing a hybrid nonwoven elastic web in which a nonwoven elastic web is bonded to a fibrous nonwoven gathered web, with the fibrous nonwoven gathered web being gathered, elongated and deflected. After being gathered as a result of being formed directly on the surface of the nonwoven elastic web being held, the nonwoven elastic web is stretched and relaxed from the deflected state or length and relaxed to the undeflected length or condition. It is to provide a method of manufacturing.

It is still another object of the present invention to provide a hybrid elastic nonwoven web in which a fibrous nonwoven gathered web is formed on a surface of the elastic nonwoven web with a gatherable state and at the same time a nonwoven elastic web is joined.

Another object of the present invention is to provide a hybrid nonwoven elastic web formed by the methods of the present invention.

It is yet another object of the present invention to provide a new method of forming a gathered nonwoven web that will have elastic properties alone from inelastic materials.

Another object of the present invention is a novel method of forming a gathered nonwoven elastic web, wherein the gatherable web is formed directly on the surface of the nonwoven elastic web, while the nonwoven elastic web is maintained in an elongated and biased state, thereby gathering Allow the webs to be bonded individually to the nonwoven elastic web, and then relax the nonwoven elastic web from its elongation and deflection conditions or lengths to the relaxed and undeflected conditions or lengths so that the gatherable webs are gathered. It is to provide a new method of separating from an elastic web to form an elastic gathered web.

It is still another object of the present invention to provide a gatherable web in a novel method of forming a gathered nonwoven elastic web directly on a stretchable porous forming surface while maintaining the forming surface in an elongated state, thereby gathering the gathering web. Allow the web to bond individually to the stretchable, shrinkable forming surface, and shrink the forming surface to gather the gatherable web, and then separate the gathered web from the forming surface to form a gathered web having elastic properties. To provide a new way of doing this.

Another object of the present invention is to provide a gathered nonwoven web having elastic properties formed in the method of the present invention.

Further objects and a wide range of applications of the present invention will become apparent to those skilled in the art from the following description. However, it is to be understood that the following detailed description of the preferred embodiments of the present invention has been described only as illustrative, since various changes or modifications within the spirit or scope of the present invention will be apparent to those skilled in the art in light of the present description. The present invention relates to a method for producing a hybrid nonwoven elastic web composed of a nonwoven elastic web adapted to a fibrous nonwoven gathered web. In particular, it consists of a gathered nonwoven fibrous web bonded to the nonwoven elastic web in a relaxed, unstretched state by the method of the invention, the nonwoven elastic web being stretched to relax from the deflected length and to an unbiased unstretched length. A hybrid nonwoven elastic web is provided that relaxes to allow the fibrous nonwoven gathered web to gather. An important feature of the method of the present invention is that the gatherable fibrous nonwoven web is directly formed on the surface of the nonwoven elastic web while maintaining the nonwoven elastic web in an elongated, deflected and extended state.

The nonwoven elastic web can be formed by, for example, meltblowing or other method for forming the nonwoven elastic web. For example, the nonwoven elastic web may be a split fibrous web of elastic film opposite the meltblown fibrous nonwoven elastic web. The formed nonwoven elastic web has regular relaxation, unextension and unbiased length. Thereafter, the nonwoven elastic web can be stretched and extended to a deflected length.

In the next step of process, the nonwoven elastic web is extended, elongated, and stretched to the surface of the nonwoven elastic web by, for example, a meltblown or spunbonding method or a method of forming a gatherable fibrous nonwoven web. Form directly while maintaining the deflected length. During formation of the fibrous nonwoven gathering web, the nonwoven elastic web is maintained at an elongated length of at least about 125%, corresponding to at least about 1 and 1/4 of the relaxed, unbiased length of the nonwoven elastic web. For example, the elongated, deflected length of the nonwoven elastic web is maintained in a range from at least about 125% of the relaxed, undeflected length of the nonwoven elastic web to at least about 700% of the relaxed, undeflected length of the nonwoven elastic web. You can.

The fibrous nonwoven gathering web is bonded to the nonwoven elastic web while maintaining the nonwoven elastic web at its extended, elongated, deflected length. As a result, a hybrid nonwoven elastic web is formed that includes a nonwoven elastic web bonded to a gatherable fibrous nonwoven web. Since the gatherable fibrous nonwoven web is formed directly on the surface of the nonwoven elastic web while maintaining the nonwoven elastic web at its elongation, deflection length, the nonwoven elastic web is extended, stretched and deflected at the bottom of this step, and the gatherable fibrous nonwoven web Is not gathered but is in a gatherable state.

In one embodiment of the present invention, bonding the gatherable fibrous nonwoven web to the nonwoven elastic web can be accomplished by fusing each other by heat bonding the two webs. The heat bond is in a temperature range between about 50 ° C., which is at least one melting temperature of the material used to form at least one of the two webs, to at least one melting temperature of the material used to form at least one of the two webs. You can do this at Heat adhesion at high processing efficiencies may be performed at temperatures above the melting temperature of the one or more materials used to form the web. This heat bonding can also be performed under suitable conventional pressurization conditions. If desired, conventional sonic bonding techniques can be used in place of heat bonding techniques.

In another embodiment of the present invention, bonding the gatherable fibrous nonwoven web to the stretched nonwoven elastic web entangles the individual fibers of the gatherable fibrous nonwoven web with the nonwoven elastic web during formation of the gatherable fibrous web on the surface of the elastic web. Simply achieved. In the case where the nonwoven elastic web is a fibrous nonwoven elastic web formed by, for example, melt blowing, the entanglement of the individual fibers of the gatherable fibrous nonwoven web and the fibrous nonwoven elastic web is such that the individual fibers and the fibrous elastic web of the gatherable fibrous web Is achieved by the entanglement of the individual fibers. In the case where the nonwoven elastic web is a cracked film, the bonding of the fibrous nonwoven web and the film is accomplished by entanglement of the individual fibers of the gatherable fibrous web in the cracks of the film.

In another embodiment of the invention described below, the bonding between the two webs is accomplished by also forming a nonwoven elastic web from the adhesive elastic material.

In any of the methods of the present invention, joining the two webs together may be further enhanced by forming a gatherable web on the surface of the elastic web and then applying pressure to the two webs. In addition, in either embodiment, the bonding of the two webs can be further enhanced by applying an adhesive material to the top surface of the nonwoven elastic web before forming the gatherable fibrous nonwoven web.

After the two webs are joined to each other to form the hybrid elastic web, the deflection force is removed from the hybrid nonwoven elastic web and the hybrid elastic web is relaxed to its normal relaxation and unbiased length. Since the gatherable fibrous nonwoven web is joined in the stretched state of the nonwoven elastic web, relaxing the hybrid nonwoven elastic web causes movement by the nonwoven elastic web in which the gatherable web is contracted, thereby gathering.

The gatherable fibrous nonwoven web is gathered by reducing the bias on the hybrid nonwoven elastic web and then rolled up in the roll to store and ship the hybrid nonwoven elastic web. Thereafter, the hybrid elastic web can be used to form a wide range of products such as, for example, diaper sheaths.

Alternatively, the gathered nonwoven web can be gathered by the retraction of the nonwoven elastic web. In this embodiment, the gathered nonwoven webs may be used alone or in combination with various other web or film materials to form a number of different products. Interestingly, the separated gathered nonwoven web retains its gathered arrangement to a considerable extent and also exhibits elasticity. The gathered nonwoven web may be formed directly on the surface of the elastic nonwoven web in an extended state under gatherable conditions, as described above.

After forming on the surface of the nonwoven elastic web, the gatherable fibrous nonwoven web is separated and bonded to the nonwoven elastic web while maintaining the nonwoven elastic web at its extended, stretched, and deflected lengths. This forms a hybrid nonwoven elastic web comprising a nonwoven elastic web and a gatherable fibrous nonwoven web, wherein the gatherable fibrous nonwoven web is separated from and bonded to the nonwoven elastic web. Since the gatherable fibrous nonwoven web is formed directly on the surface of the nonwoven elastic web with the nonwoven elastic web held at its elongated, elongated, deflected length, in this step of the process the nonwoven elastic web is in an extended, elongated and deflected state, The gatherable fibrous nonwoven web is not gathered but is in a gatherable state. Separately joining the gatherable fibrous nonwoven web to the elongated, nonwoven elastic web entangles the individual fibers of the gatherable fibrous nonwoven web with the nonwoven elastic web while forming the gatherable fibrous nonwoven web on the surface of the nonwoven elastic web. Is achieved. The separable bonding of the fibrous nonwoven web gatherable to the fibrous nonwoven elastic web in which the nonwoven elastic web is formed by, for example, meltblowing, is accomplished by entangled the gatherable fibrous web with the individual fibers of the fibrous nonwoven elastic web. When the nonwoven elastic web is a cracked film, separable bonding of the fibrous nonwoven web and the nonwoven elastic web is accomplished by entangled individual fibers of the gatherable fibrous web in the gaps of the cracked film.

After two webs are separably bonded to each other to form a hybrid elastic web, and then the deflection force is removed from the hybrid nonwoven elastic web, the hybrid elastic web may not be deflected or deflected due to the contraction of the stretched nonwoven elastic web. Shrink to length. Since the gatherable fibrous nonwoven web is detachably bonded to the nonwoven elastic web when the nonwoven elastic web is extended and elongated, shrinking the hybrid nonwoven elastic web causes movement by the nonwoven elastic web where the gatherable web is contracted and elastic. Gathered to the surface of the web.

After the gathering of the gatherable fibrous nonwoven web occurs by reducing the biasing force of the hybrid nonwoven elastic web, the gathered fibrous nonwoven web can be separated from the nonwoven elastic web and the gathered web can be rolled up, for example, stored up. After separating the fibrous nonwoven gathered web from the nonwoven elastic web, the nonwoven elastic web can be used again as a forming surface.

After separation from the nonwoven elastic web, the gathered fibrous nonwoven web has a gathered arrangement, and after the gatherable fibrous nonwoven web applies stretching and deflection forces in the gathered direction, the gathered web is stretched to the extent that the gathering is allowed. do. Importantly, when the stretching and deflection forces are relaxed, the elongated gathered fibrous nonwoven web substantially contracts to the gathered arrangement and length it will have after it is separated from the nonwoven elastic web. That is, the fibrous nonwoven gathered web exhibits elastic properties and properties. When the gathered web is separated from the nonwoven elastic web, it is surprising that the gathered web retains the gathered arrangement. However, it is even more surprising that when the separated gathered fibrous nonwoven web is stretched to an extended length, the separated gathered fibrous nonwoven web exhibits elastic properties such as returning to at least about 40% of its elongation. . That is, the separated fibrous nonwoven webs exhibit the elastic or elastomeric properties as described above. Indeed, the inventors have found that the gathered fibrous nonwoven web exhibits these elastic properties even when the gathered fibrous nonwoven web is formed from an inelastic material such as polypropylene.

The gatherable fibrous nonwoven web suitably comprises at least one meltblown fibrous nonwoven web. Separate methods that can be used to form the gatherable fibrous nonwoven web include spunbonding or other methods of forming the gatherable fibrous nonwoven web. The gathered fibrous nonwoven web may be formed entirely from inelastic material or from a mixture of one or more inelastic materials. However, the gathered fibrous nonwoven may be formed from a mixture of one or more inelastic materials and one or more elastic materials or one or more elastic materials. Inelastic materials for forming the gatherable fibrous nonwoven web include inelastic polyester materials, inelastic polyolefin materials or mixtures of one or more inelastic polyester materials and one or more inelastic polyolefin materials. Examples of inelastic polyester materials include polyethylene terephthalate. As an example of an inelastic polyolefin, the inelastic polypropylene which designation brand name is PF101 is mentioned.

Alternatively, the need for elastic nonwoven webs can be eliminated by directly forming the gathered nonwoven webs on stretchable and retractable surfaces, such as stretchable and retractable reticular screens under gatherable conditions.

In one particular embodiment of the method of the invention, the adhesive fibrous nonwoven elastic web is for example an adhesive elastic material, such as an ABA 'block copolymer or a mixture of ABA' block copolymers with poly (alpha-methylstyrene) ( Wherein A and A 'are respectively thermoplastic polystyrene or polystyrene homolog end blocks, and B is an elastic polyisoprene intermediate block). In some embodiments, A may be a thermoplastic polystyrene or polystyrene homolog end block, such as A '. The stretchable fibrous nonwoven elastic web is then stretched by extending to an extended length, and the gatherable web is, for example, while maintaining the fibrous nonwoven elastic web at its elongated length on the surface of the adhesive fibrous nonwoven elastic web. It is formed by spunbonding directly.

As a result of the fibrous nonwoven elastic web being adhesive, a gatherable fibrous nonwoven web is simultaneously formed and bonded by the adhesion of the surface of the adhesive fibrous nonwoven elastic web. This method of carrying has a non-gathered gatherable fibrous web joined by the adhesive force of the adhesive fibrous nonwoven elastic web, wherein the mutual bonding of the two webs occurs during formation of the gatherable fibrous nonwoven web on the surface of the fibrous nonwoven elastic web. The hybrid nonwoven elastic web achieved by bonding is formed. The adhesive bond between the two webs can be increased by passing the hybrid nonwoven elastic web through the nip between the rollers when the hybrid nonwoven elastic web is pressurized, the roller after forming the hybrid web, but not fibrous adhesive The nonwoven elastic web is not heated before relaxing. Adhesive bonding can be further enhanced by applying an adhesive material to the surface of the adhesive fibrous nonwoven elastic web prior to forming the gatherable web thereon.

The hybrid nonwoven elastic web can then be relaxed to its normal, unbiased length. Since the gatherable fibrous nonwoven web is bonded to the adhesive fibrous nonwoven elastic web while the adhesive fibrous nonwoven elastic web is in the stretched state, relaxing the hybrid nonwoven elastic web results in the adhesive fibrous nonwoven elastic web shrinking. This results in the gathering being moved by the fibrous nonwoven elastic web.

After the gathering of the gatherable fibrous nonwoven web has occurred, the hybrid nonwoven elastic web can be rolled up into a roll to store and ship. In order to avoid sticking of the exposed surface of the adhesive fibrous nonwoven elastic web when rolling up the hybrid nonwoven elastic web, it is suitable to use a gatherable second fibrous nonwoven web on the exposed side of the fibrous nonwoven elastic web before the gathering step. Alternatively, butcher paper may be applied to the exposed adhesive surface of the adhesive fibrous nonwoven elastic web before and after gathering the gatherable web, the latter being removed before use of the hybrid nonwoven elastic web. . Thereafter, the hybrid elastic web can be used to form a wide range of products.

The present invention also relates to a hybrid nonwoven elastic web of nonwoven elastic webs bonded to a gathered fibrous elastic web, the hybrid web being formed by any of the methods of the present invention. In particular, the hybrid nonwoven elastic webs in the relaxed, unextended state may be applied to the gathered fibrous nonwoven webs as a result of the nonwoven elastic webs being extended, stretched, and deflected from the unstretched, unstretched, unstretched lengths. It consists of a bonded nonwoven elastic web. Examples of elastomeric materials used to form fibrous nonwoven elastic webs include polyester elastomeric materials, polyurethane elastomeric materials, and polyamide elastomeric materials.

Other elastomeric materials used to form fibrous nonwoven elastic webs include (a) ABA 'block copolymers, where A and A' are each thermoplastic polymer end blocks comprising styrene-based moieties, and A is the same thermoplastic as A '. Polymer end blocks (eg, poly (vinyl arene)), and B is an elastomeric polymer intermediate block such as conjugated diene or lower alkene). The A and A ′ end blocks can be selected from the group comprising polystyrene and polystyrene homologs, and the B middle block can be selected from the group comprising polyisoprene, polybutadiene or poly (ethylene-butylene). When A and A 'are selected from the group consisting of polystyrene homologs, and B is poly (ethylene-butylene), the materials that can be mixed with these block copolymers are ethylene, propylene, butene, other lower alkenes or any of these materials. Polymers comprising at least one copolymer. When A and A 'are selected from the group comprising polystyrene or polystyrene homologs, and B is a polyisoprene intermediate block, the material for mixing with this type of block copolymer is poly (alpha-methylstyrene).

The gatherable web includes at least one fibrous nonwoven web comprising inelastic fibers that may be formed by meltblowing, spunbonding or other methods to form the gatherable fibrous nonwoven web. Suitable as materials for forming the gatherable web are polyester materials, polyolefin materials, or mixtures of one or more polyester materials and one or more polyolefin materials. Examples of the polyester material include polyethylene terephthalate. Examples of the polyolefin material include polypropylene.

In the accompanying drawings, like reference numerals denote like structures. In particular in FIG. 1, the meltblown fine fibers 10 formed by the conventional meltblowing die 12 move around the rollers 18 and 20, as indicated by arrows 16 in FIG. 1. It can be seen that the focus on the porous focusing screen (14). The material used to form the meltblown microfibers 10 is an elastomeric material, although the reason will be apparent later. The porous focusing screen 14 is operated by rotary rollers 18 and 20, which are then operated by conventional actuators (not shown). For simplicity, although not shown in the drawings, a conventional vacuum box was placed between the rollers 18 and 20 and below the bottom surface of the upper portion of the screen 14. The vacuum box assists in the retention of the fine fibers 10 on the top surface of the screens 14. When the meltblown fine fibers 10 are deposited on the moving focus screen 14, these fine fibers are entangled with each other and adhere to form an adhesive fiber nonwoven elastic web 22. The entangled adhesive fibrous nonwoven elastic web 22 is carried by the porous focusing screen 14 to the nip or gap 24 between the rotary roller 20 and the rotary nip roller 26. Adjusting the nip or gap 24 between the two rollers 20 and 26 to secure the fibrous nonwoven elastic web 22 without adversely affecting the rollers 20 and 26 against the web 22. To be combined. The rotational speeds of the rollers 20 and 26 are adjusted so that the surface circumferential speeds of the rollers 20 and 26 are equal to the speed of the porous focusing screen 14 which moves substantially.

After laying down on the surface of the porous screen 14, the adhesive web 22 can be subjected to the elongation and relaxation steps described later without the meltblown fine fibers 10 being adversely affected. In case of insufficient connection to form a (e.g., after exerting stretching force, the web is separated and loses cohesion), the adhesion of the fine fibers 10 to each other, for example, raises the roller 26 moderately. The microfibers 10 can be promoted by heating and bonding the microfibers 10 to each other by maintaining at the temperature set at the above temperature, which temperature varies depending on the required degree of adhesion and the adhesive properties of the material used to form the microfibers 10. Typical heat bond temperatures are between about 50 ° C. below the melting temperature of at least one of the materials used to form the web and between the melting temperatures of at least one of the materials used to form the web. However, it is also possible to use high processing efficiency temperatures in excess of the melting temperature of the material. After passing through the nip 24, the fibrous nonwoven elastic web 22 is formed by a second nip roller 32 formed between the rotating roller 30 and the second rotating nip roller 32 by the action of the rollers 20 and 26. Transfer to or through gap 28. The rotation of the rollers 30 and 32 is adjusted to make the surface circumferential speeds of the rollers 30 and 32 larger than the surface circumferential speeds of the rollers 20 and 26. Adjusting the nip 28 between the two rollers 30 and 32 firmly secures the fibrous nonwoven elastic web 22 without adversely affecting the rollers 30 and 32 against the web 22. Combine. As a result of increasing the surface circumferential speeds of the rollers 30 and 32 compared to the surface circumferential speeds of the rollers 20 and 26, the longitudinal or machine direction (MD) deflection forces result in a fibrous nonwoven elastic web 22 In addition, the web 22 is extended to a length that is extended and deflected in the longitudinal direction or the machine direction MD.

The elongation of the fibrous nonwoven elastic web 22 in the region 34 between the rollers 20 and 26 and the rollers 30 and 32 is, for example, the surface circumference of the rollers 20 and 26. It can be changed by changing the surface circumferential speeds of the rollers 30 and 32 with respect to the speed. For example, when the surface circumferential velocity of the rollers 30 and 32 is twice that of the rollers 20 and 26, the fibrous nonwoven elastic web 22 is stretched by about twice as long. That is, stretched to an extension length corresponding to about 200% of its initial relaxation, unstretched, unbiased length. The fibrous nonwoven web 22 is suitably stretched to an elongated length that corresponds to at least about 125% of its initial relaxed, unbiased length. In particular, the fibrous nonwoven web 22 has an extended length from at least about 150% of the relaxed, undeflected length of the fibrous nonwoven web 22 to at least about 700% of the relaxed, undeflected length of the fibrous nonwoven web 22. It is suitable to extend the elongated length from at least about 150% to at least about 700% of the relaxed, undeflected length of the fibrous nonwoven web 22.

The fibrous nonwoven elastic web 22 is stretched by the cooperative action of the rollers 20 and 26 and the rollers 30 and 32, and then the web 22 is indicated by an arrow 38 in FIG. As above, it moves on the 2nd porous focusing screen which moves. The second porous focusing screen 36 moves and operates around the rotary roller 30 in relation to the rotary roller 40. Rotary rollers 30 and 40 are in turn operated by the same conventional actuating device (not shown) which is the same as the device for actuating rotary rollers 18 and 20. For simplicity, although not shown in the drawings, a conventional vacuum box was placed between the rollers 30 and 40 and below the bottom surface of the upper portion of the screen. The vacuum box assists in the retention of the web 22 on the top surface of the screen 36. The stretched fibrous nonwoven elastic web 22 is conveyed by a second porous focusing screen 36 to a nip or gap 42 formed between the rotary roller 40 and the third rotary nip roller 44. The rotation of the rotary rollers 40 and the nip rollers 44 is adjusted to make the surface circumferential speeds of the two rollers 40 and 44 substantially equal to the surface circumferential speeds of the rollers 30 and 32.

The surface circumferential speed of the rollers 40 and 44 is maintained at substantially the same surface circumferential speed as that of the rollers 30 and 32, and the nip 42 is adjusted so that the rollers 40 and 44 are web Since the fibrous nonwoven elastic web 22 is firmly held without adversely affecting the stretched state, the stretched state of the fibrous nonwoven elastic web 22 is maintained, while the fibrous nonwoven elastic web 22 is the second porous focusing. It is carried by the screen 36.

The stretched fibrous nonwoven elastic web 22 is carried by the second porous focused screening 36, while the meltblown microfibers 46 formed by the conventional meltblowing die 48 are stretched fibrous nonwovens. Meltblown directly on the upper surface of the elastic web 22 to form a gatherable adhesive fibrous web 50, which is disposed on the upper surface of the elongated fibrous nonwoven elastic web 22. Care must be taken to adjust the length between the die tip of the meltblowing die 48 and the elastic web 22 and the speed at which the elastic web 22 passes under the die tip of the meltblowing die 48, while the elastic material 22 If the adjustment to change the material or mixture of these materials is not made properly, the die tip will apply the elastic web 22 upon releasing hot air. When focusing the meltblown fine fibers 46 on the upper surface of the fibrous nonwoven elastic web 22, these fine fibers are entangled with each other and are bonded to form a gatherable adhesive fibrous nonwoven elastic web 22. Depending on the distance between the die tip of the meltblowing die 48 and the upper surface of the elongated fibrous nonwoven elastic web 22, the meltblown fine fibers 46 are mechanically entangled with the fibers of the elastic web 22. Can be.

Generally speaking, as the distance between the die tip of the meltblowing die 48 and the top surface of the elongated fibrous nonwoven elastic web 22 increases, the mechanical properties of the fibers of the web 50 and the fibers of the web 22 increase. The entanglement is reduced. In order to ensure mechanical entanglement between the fibers of the web 50 and the fibers of the web 22, the distance between the die tip of the melt blowing die 48 and the top surface of the web 22 is about 25 inches (63.5 cm). Should be less than or equal to The distance between the die tip of the meltblowing die 48 and the top surface of the web 22 is suitably between about 15.2 cm (6 inches) and about 40.6 cm (16 inches). Depending on the material used to form the webs 22 and 50 and the distance between the die tip of the meltblowing die 48 and the top surface of the web 22, the fibers of the gatherable web 50 are elastic webs. It can be made to adhere to the fiber of (22) to some extent.

The suitable material used to form the fibrous nonwoven elastic web 22 is preferably selected after selecting the material or materials to be used to form the fibrous nonwoven elastic web 50. In particular, the material selected to form the gatherable fibrous nonwoven web 50 should be a material that forms the gatherable web 50 by the contractive force of the fibrous nonwoven elastic web 22. Since the retractive force of the web 22 depends on the material selected to form the web 22, the material selected to form the web 22 should be selected so that the retractive force of the web 22 can gather the web 50. . Examples of materials for use in forming the webs 22 and 50 will be described later.

Depending on the properties required for the final product, the materials used to form the fibers of the two webs 22 and 50 and the process step conditions used, the two adhesive webs 22 and 50 may be produced in various ways. Can be bonded to each other. For example, where a finely weak bond between two webs 22 and 50 is required, the two webs 22 and 50 may be individually meltblown in a gatherable fibrous nonwoven web 50. The fibers and the fibrous nonwoven elastic web 22 can be joined together only by entanglement with the individual meltblown fibers, which is done during the formation of the web 50 on the elongated surface of the web 22. In this embodiment, the two webs 22 and 50 can be separated from each other after applying a relatively small force, such as a light picking force or a rubbing force that exerts a user's finger. The two adhesive webs 22 and 50 can be separated from each other more. If stronger bonding is required between the two adhesive webs 22 and 50, the bonding of the fibrous nonwoven web 50 that is gatherable to the fibrous nonwoven elastic web 22, on the one hand, is a fibrous nonwoven elastic web 22. ) Can be achieved by heat bonding the two webs 22 and 50 to each other while continuing to maintain their elongated length. This heat bonding can be achieved, for example, by passing two webs 22 and 50 between the rollers 40 and 44, which rollers 40 and 44 are two webs ( 22) and (50) are arranged to apply the appropriate heat-junction temperature and pressure.

For example, bonding of the fibrous nonwoven web 50 gatherable to the fibrous nonwoven elastic web 22 may be accomplished by heat bonding of the two nonwoven webs 22 and 50, and the rollers 40 and ( 44 is about 50 ° C. below the melting point of at least one of the materials used to form the webs 22 and 50 to near the melting point of at least one of the materials used to form the webs 22 and 50. Keep within the temperature range of. However, at high processing efficiencies, the heat bonding can be done at different melting points of one or more materials used to form the two webs 22 and 50, because the webs 22 and 50 are briefly suspended. This is because they are exposed to high temperatures. Pressurized heating bonding between the two webs can be performed at a normal suitable bonding pressure by adjusting the nip 42. Other conventional methods for heat bonding the two webs 22 and 50 can be used in place of the heat contacting step. For example, a conventional sound wave bonding device (not shown) may be used in place of the heat bonding devices 40 and 44. The joining between the two webs 22 and 50 can usually only slightly improve the webs 22 and 50 through the house 42, because of the two pressures This is because the entanglement of the individual fibers of the two webs 22 and 50 is improved by being applied to the webs 22 and 50.

After the fibrous nonwoven elastic web 22 is joined to the gatherable fibrous nonwoven web 50 (with or without separation depending on the final product required) to form the hybrid nonwoven elastic web 52, then the fibrous nonwoven elastic web 52 is formed. A pair of rotary nip rollers 56 is applied to the biasing force applied to the web 22, such as a hybrid nonwoven elastic web 52, which includes a nonwoven elastic web 22 and a gatherable fibrous nonwoven web 50. And through the nip or gap 54 formed by 58 to relax. The nip 54 is adjusted to firmly couple the rollers 56 and 58 to the hybrid web 52 without adversely affecting the hybrid web 52. Adjusting the rotation of the pair of nip rollers 56 and 58 causes the surface circumferential velocity of the nip rollers 56 and 58 to relax the hybrid nonwoven elastic web 52 and as a result of its elasticity , Shrink to unbiased length. Relaxing and shrinking the hybrid nonwoven elastic web 52 to its relaxed, unbiased length results in a gatherable fibrous nonwoven web 50 that is joined to the fibrous nonwoven elastic web 22 and conveyed, i. And the upper surface of the shrink fibrous nonwoven elastic web 22.

After relaxing and shrinking the hybrid nonwoven elastic web 52, the hybrid web 52 can be rolled up to the supply roller 60 to be stored and shipped. Thereafter, the hybrid nonwoven elastic web 52 may be used in various products, such as diaper sheaths or other garment altars.

Alternatively, when separating the gathered nonwoven web 50 from the elastic nonwoven web 22, the separation of the two webs 22 and 50 causes the fibrous nonwoven gathered web 50 to be two rotary nip rollers. The nip 62 is passed between 64 and 66 and the nonwoven elastic web 22 is passed through the nip 68 between two rotary nip rollers 70 and 72. Adjusting the nips 62 and 68 combines the rollers 64 and 66 with the web 50 without adversely affecting the web 50 and the rollers 70 and 72 with the web. It is combined with the web 22 without adversely affecting the 22. After separating the two webs 22 and 50, the two webs 22 and 50 are wound around the storage rollers 74 and 76. Care must be taken in winding the fibrous nonwoven gathered web 50 so that the web 50 is not stored under high tension or deflected under ungatherable conditions, because the web 50 is rolled up. When stored in an elongate, non-gatherable condition, the web 50 loses its gathering holding capacity, and therefore, the loss of the gathering in the web 50 results in the loss of the elastic properties of the web 50. Thus, in order to retain the gathered state of the web 50 while storing the web 50 on the one hand, the rotation of the storage roller 76 is adjusted to reduce the surface circumferential velocity of the storage roller 76 by the roller 64 and Make it equal to or slightly larger than the surface circumferential speed of (66).

When separated from the nonwoven elastic web 22, the gathered fibrous nonwoven web 50 exhibited a creped or gathered appearance. Thus, after applying the stretching force in the machine direction (the direction substantially perpendicular to the line of the gathering), the web 50 permits gathering, for example, the web 50 is generally planar arrayed against the gathered arrangement. When stretched to have, and surprisingly, when the stretching force was relaxed in the gathered state, the gathered web 50 exhibited the elastic properties defined in the present invention. The gathered web 50 exhibited elastic properties even when the web 50 was formed from an inelastic material such as polypropylene sold under the trade name PF 301 of Himont Corporation.

The fibrous nonwoven elastic web 22 portion of the hybrid nonwoven elastic web 52 may be formed from an elastic material that may be formed from the fibrous nonwoven elastic web 22. Examples of elastomeric materials used in the formation of the fibrous nonwoven elastic webs 22 include polyester elastomeric materials, e. children. Polyester elastomer materials, polyurethane elastomer materials, such as B.F, sold under the trade name Hytrel under E.I. Du Pont De Nemours and Co. Polyurethane elastomer materials sold under the trade name Estane of BF Goodrich & Co., polyamide elastomer materials, such as polyamide elastomer materials sold under the trade name Pebex of Rilsan Company. do.

Other elastomeric materials used to form the fibrous nonwoven elastic web 22 include (a) elastomeric ABA 'block copolymers, where A and A' are each thermoplastic polymer end blocks comprising styrene moieties, and A is A ' May be the same thermoplastic polymer end block, for example poly (vinyl arene), B is an elastomeric polymer intermediate block such as conjugated diene or lower alkene] and (b) at least one polyolefin or poly (alpha-methylstyrene) And elastomer ABA 'block copolymer material, wherein A and A' are each a polymeric thermoplastic end block containing a styrene moiety, and A can be the same thermoplastic polymer end block as A ', for example poly (vinyl arene) And B is an elastomeric polymer intermediate block such as conjugated diene or lower alkene. The A and A ′ materials may be selected from the group consisting of materials comprising polystyrene or polystyrene homologues, and the B material may be selected from the group consisting of materials comprising polyisoprene, polybutadiene and poly (ethylene-butylene). have. General forms of this material are described in Des Marais, U.S. Patent No. 4,323,534, and in Jones, U.S. Patent No. 4,355,425, and in the booklet of Shell Company. Commercially available elastomer A-B-A 'block copolymer having a saturated or necessarily saturated poly (ethylene-butylene) intermediate block “B” represented by the following structural formula:

Wherein x, y and n are positive integers and the polystyrene end blocks A and A '

(Wherein n is a positive integer equal to or different from A and A ')

Is often referred to as the S-EB-S block copolymer, and commercially available products thereof include the trade names KRATON G, such as KRATON G 1650, KRATON G 1652 and KRATON GX 1657, available from Shell Chemical Company. .

Other elastomeric resins that can be used are A-B-A 'block copolymers, where A and A' are polystyrene end blocks as defined above, and B is a polybutadiene intermediate block represented by the following structural formula.

(Where n is a positive integer).

This material is often referred to as the S-B-S block copolymer, and commercially available products thereof include the trade names KRATON D from Shell Chemical Company, for example KRATON D 1101, KRATON D 1102 and KRATON D 1116. Other S-B-S block copolymer materials include those sold under the trade name Solprene 418 by Phillips Petroleum Company. Another elastomeric resin that can be used is an ABA 'block copolymer, where A and A' are polystyrene end blocks as defined above, B is a polyisoprene intermediate block, wherein the intermediate block is of the following structural formula: Is shown.

(Where n is a positive integer), these block copolymers are often referred to as SIS block copolymers, for example the trade names KRATON D of Shell Chemical Kamani, for example KRATON D 1107, KRATON D 1111, KRATON D 1112 and KRATON D 1117.

Representative properties of the KRATON D and KRATON G at about 23.3 ° C. (74 ° F.) are summarized in Tables 1 and 2 below.

TABLE 1

KRATON D

TABLE 2

KRATON G

(Note): 1: ASRM method D412-tensile test jaw separation rate about 25.4 cm (10 inches) / min.

2: Representative properties measured on film cast in toloene solution.

3: knit polymer concentration, 25% wt.

4: knit polymer concentration, 20% wt.

5: The characteristic measured by extrapolating the oil content of the result measured about the oil cast film cast from a toluene solution to zero.

6: ratio of the total molecular weight of the end block (A + A ') to the molecular weight of the B middle block. For example, with respect to KRATON G-1650, the molecular weight of the end block (A + A ') is 28% of the molecular weight of the A-B-A' block copolymer.

Meltblowing of S-EB-S KRATON G block copolymers in their pure form provides high temperatures and low processing efficiencies, such as at least about 288 ° C (550 ° F to 329 ° C (625 ° F)) and at least per minute die tubing. Except in the case of processing efficiencies of about 0.14 g or less, it has proved difficult, in order to avoid such high temperature and low draw-put guns, a mixture of certain materials and several different types of KRATON G materials can be meltblown satisfactorily. For example, a mixture of a specific polyolefin material with an S-EB-S block copolymer produces a material that can be meltblown, in particular the polyolefin is KRATON G S-EB- When mixed with an S block copolymer, the polyolefin is a polymerization comprising a copolymer of ethylene, propylene, butene, other lower alkenes or a mixture of one or more of these materials. Particularly suitable polyolefins for mixing with KRATON G S-EB-S block copolymers are polyethylene, and suitable polyethylene is the tradename Petrothene Na 601 from USI Chemical Company (also Na 601 or Na 601).

U.S.I. According to the information provided by Chemical Company, Na 601 describes low molecular weight, low density polyethylene for use in the fields of heating melting, adhesives and coatings. The document also states that Na 601 has the following nominal values. (1) Brock feed viscosity, measured at ASTM D 3236, 8500 cP at 150 ° C. and 3300 cP at 190 ° C., (2) Density of 0.903 g per cubic centimeter as measured by ASTM D 1505, (3) Equivalent melt index of 2000 g per 10 minutes as measured by ASTM D 1238, (4) Ring and ball softening point 102 ° C., measured by ASTM E 28, (5) Per square inch, measured by ASTM D 638 850 pounds tension, (6) 90% elongation, (7) stiffness, T _F (45,000) and (8) penetration hardness of -34 ° C, measured at ASTM D 638, 25 ° C (77 ° F) At 3.6 (tenth of a millimeter).

Na 601 is believed to have a number average molecular weight (Mn) of 4,600, a weight average Bunjarang (Mw) of 22,400, and a Z average molecular weight (Mz) of 83,300. The multiple dispersion of Na 601 (Mw / Mn) is about 4.87.

Where Mw is the various molecular weights of the individual molecules in the sample, and n is the number of molecules in the given sample with the given molecular weight Mw.

When the polyolefin was mixed with the S-I-S and S-B-S block copolymers and then meltblowned, the mixture appeared to be unsuitable and proved to be unsatisfactory so far. However, a good material for mixing with the S-I-S block copolymer is poly (alpha-methylstyrene), and suitable poly (alpha-methylstyrene) is commercially available under the tradename 18-210 of Amoco.

The gatherable fibrous nonwoven web 50 portion of the hybrid nonwoven elastic web 52 formed by the method of the present invention is suitably formed from any gatherable material that can be formed from the gatherable fibrous nonwoven web 50. For example, the gatherable fibrous nonwoven web 50 may be formed from an inelastic material and an elastic material, a mixture of one or more inelastic materials, or a mixture of one or more elastic materials and two or more inelastic materials. Preferably, the gatherable fibrous nonwoven web 50 can be melt blown or spunbonded from a fiber forming and formed from a gatherable inelastic material. Examples of the fiber forming material used to form the gatherable fibrous nonwoven webs include polyester materials, polyolefin materials or mixtures of one or more polyester materials with one or more polyolefin materials. Polyethylene terephthalate is mentioned as an example of polyester fiber forming material. Polypropylene is mentioned as an example of a fiber forming polyolefin material. Examples of polypropylene materials include the trade names PC 973 and PF 301 from Himont Company.

Representative properties of the Himont Co. PC-973 polypropylene are about 0.900 g per cubic centimeter, density, melt flow rate obtained by ASTM D 1238, condition of 35 g / min, ASTM D 638, as measured by ASTM D 792. Tension of about 4,300 pounds (psi) in square inches, measured by ASTM D 790, B, measured by Rockwell hardness (R scale) 93, measured by flexible modulus of about 182,200, and ASTM D 785 A do. PC-973 is believed to have a number average molecular weight (Mn) of about 40,100, a weight average molecular weight (Mw) of about 172,000 and a z average molecular weight of about 674,000. The multiple dispersion (Mw / Mn) of PC-973 is about 4.29.

If the gatherable web 50 is to be separated from the elastic web 22 after gathering it, the gathered web 50 is able to detach it from the elastic web 22 and then return substantially to its gathered state. It is good. In most embodiments, the gathered state (e.g., arrangement) that appears after the gatherable fibrous nonwoven web 50 separates it from the web 22 is such that when the web 50 is individually bonded to the elastic material 22 It will be slightly longer in the gathering direction (ie machine direction) when compared to the length of the web 50 in the same amount. In other words, the web 50 will elongate slightly in the direction of separating it from the web 22 and then gathering it. Thus, the gathered, relaxed, unbiased length of the separated web 50 is equal to the gathered, relaxed, undeflected length of the web 50 while bonding the web to the elastic web 22. Will be slightly larger or equivalent.

In one particular embodiment of the invention, the hybrid nonwoven elastic web 52 is comprised of a fibrous nonwoven elastic web 22 bonded to a gatherable fibrous nonwoven web 50. The hybrid nonwoven elastic web 52 of this embodiment is different from the hybrid nonwoven elastic web 52 of the above example, wherein the joining of the two webs 22 and 50 of the hybrid nonwoven elastic web 52 is performed during the joining step. And / or without applying pressure, this bonding entangles the fibers of the gatherable nonwoven web 50 with the fibers of the nonwoven elastic web 22 while forming the web 50 on the web 22. It is stronger than the bond achieved by doing so. In this particular example, the fibrous nonwoven elastic web 22 is formed from an adhesive elastomeric material so that after forming it, the fibrous nonwoven elastic web 22 is adhesive. The adhesive fibrous nonwoven elastic web 22 is formed by melt blowing the web 22 to the porous connecting screen 14. Alternatively, a cracked adhesive nonwoven elastic film (not shown) can be used in place of the adhesive fiber nonwoven elastic web 22. Thereafter, the adhesive fibrous nonwoven nonwoven web 22 is stretched to at least about 1 and 1/4 lengths, i.e. by the coordination of the rollers 20 and 26 and 30 and 32, their relaxation, non- Stretch to a length that is at least about 130% of the deflected length. In particular, the adhesive fibrous nonwoven elastic web 22 may be loosened up to about 150% of the loose, non-deflected length of the adhesive fibrous nonwoven elastic web to about 700% or more of the loose, undeflected length of the adhesive fibrous nonwoven web 22. It is suitable to stretch.

After stretching the adhesive fibrous nonwoven elastic web 22, the web is formed by a second porous focused strip 36 in a nip or gap 42 between the rotary roller 40 and the dielectric nip roller 44. Let's do it. While forming the web 22 by the second porous focusing screen 36, the gatherable fibrous nonwoven web 50 is formed by the conventional melt blowing method, the spunbonding method, or the gatherable fibrous nonwoven web 50. It is formed directly on the upper surface of the adhesive web 22 by other conventional methods that can be used to make them, for example by a conventional carding apparatus for forming a carded web. As described in the previous example, while forming the gatherable fibrous nonwoven web 50 on the surface of the web 22, the adhesive fibrous nonwoven elastic web 22 is formed around the circumferences of the rollers 30 and 32. With respect to the speed, the surface circumferential speeds of the rollers 40 and 44 can be appropriately adjusted to maintain their elongation and biased length. As a result of the fact that after the formation of the fibrous nonwoven elastic web 22 is adhesive, an improved bonding of the adhesive fibrous nonwoven elastic web 20 to the gatherable fibrous nonwoven web 50 (only by entanglement of the two webs) Compared to when bonded) can be achieved by adhesion of the two webs 20 and 50 during formation of the gatherable fibrous nonwoven web 50 on the top surface of the fibrous nonwoven elastic web 22.

Thus, the gatherable fibrous nonwoven web 50 can be simultaneously formed and bonded to the fibrous nonwoven elastic web 22. Adhesive elastomeric materials may be used to form the adhesive fiber nonwoven elastic web 22 of this embodiment, and suitable examples of adhesive elastomeric materials include elastomer ABA ′ block copolymers, where A and A ′ are respectively Thermoplastic polystyrene end block, B is a polyisoprene intermediate block. Tri-block copolymer materials of this type are often referred to as S-I-S block copolymers, which include the trade names KRATON D, such as KRATON D 1107, KRATON D 1111, KRATON D 1112, and KRATON D 1117 by Shell Chemical Company. Alternatively, a mixture of S-I-S block copolymers and poly (alpha-methylstyrene) can be used.

Materials that can be used to form the gatherable fibrous nonwoven web 50 of this embodiment include all of the materials described above with respect to the gatherable fibrous nonwoven web 50. That is, the gatherable fibrous nonwoven web can be formed from any gatherable material that can be formed into the gatherable fibrous nonwoven web 50. For example, the gatherable fibrous nonwoven web 50 may be formed from an inelastic material and an elastic material, one or more inelastic materials, or a mixture of one or more elastic materials and two or more inelastic materials. The gatherable fibrous nonwoven web 50 is suitably formed from a gatherable inelastic material that can be fiber-blown meltblown or spunbonded. However, the gatherable fibrous nonwoven web 50 may be used to immerse the carded web on the surface of the fibrous nonwoven elastic web 22 or to form the gatherable fibrous nonwoven web 50 on the surface of the web 22. It can be formed by other methods that can be. Examples of the fiber forming material used to form the gatherable fibrous nonwoven web 50 include a polyester material, a polyolefin material or a mixture of one or more polyester materials and one or more polyolefin materials. Examples of the polyester fiber forming material include polyethylene terephthalate. Polypropylene is mentioned as an example of a fiber forming polyolefin material. Suitable among the polypropylene materials are available from Himont Company under the trade names PC 973 and PF 301.

In some cases, it is desirable to incorporate separate particles of one or more solid materials into one or both of the webs 22 and 50 during the formation of the webs 22 and 50. For example, one or more fibers, such as cotton fibers, wood pulp fibers, polyester fibers or other particles, may be incorporated into one or both of the webs 22 and 50 during their formation. This can be accomplished using conventional coformers in connection with meltblowing devices or spunbonding devices 12 and / or 48. Such coformers are known to those skilled in the art, which are generally described by the apparatus described in Anderson, U.S. Patent No. 4,100,432, which is incorporated by reference.

After forming or simultaneously bonding the gatherable fibrous nonwoven web 50 to the top surface of the fibrous adhesive nonwoven elastic web 22, the hybrid nonwoven elastic web 52 is passed through the rollers 40 and 44, and These rollers do not need to be heated or apply excessive pressure on the hybrid elastic web 52 for the reasons described above. Thereafter, the stretching and deflection forces on the adhesive nonwoven elastic web 22 are relaxed to relax and shrink the synthesized nonwoven elastic web 52. Since the gatherable fibrous nonwoven web 50 is bonded to the surface of the adhesive fibrous nonwoven elastic web 22 while the adhesive fibrous nonwoven elastic web 22 is stretched, the hybrid nonwoven adhesive web 52 is relaxed and shrunk. The gatherable fibrous nonwoven web 50 is shrunk and gathered into a softly batted or entangled web 50 bonded to the surface of the elastic web 22.

Example 1

60% by weight ABA ′ block copolymer with polystyrene “A” and “A” end blocks and poly (ethylene-butylene) “B” intermediate block (trade name KRATON GX 1657 from Shell Chemical Company) and polyethylene silver (USI Chemical A blend of 40 wt% of the company's trade name PE Na 601) was meltblended to provide a preformed fibrous nonwoven elastic web in roll-up form.

Pretreatment Meltblowing of the fibrous nonwoven elastic web was performed by extruding the mixture of materials through a meltblowing die with 30 extrusion tubules per inch of line segment of the die tip. Each of these tubules was about 0.0363 cm (0.0145 inches) in length and about 0.283 cm (0.113 inches) in length. This mixture was extruded through the tubules at a rate of about 0.52g per minute tubing at a temperature of about 313 ° C (595 ° F).

The extrusion pressure applied to the mixture was measured at 73 pounds per square inch of gauge of the customs. The die tip arrangement was adjusted to retract about 0.225 cm (0.090 inches) inward from the plane of the outer surface of the air plate forming the forming air gap on either side of the tubule. The air plates were adjusted to form two forming air gaps, one on each side of the extruded tubing, with an air gap of about 0.168 cm (0.067 inch). Forming air for meltblowing the mixture was fed to the air gap at a temperature of about 332 ° C. (600 ° F.) and a pressure of about 4 pounds per square inch of gauge. The meltblown fibers thus formed were blown onto a forming screen which is about 38 cm (15 inches) away from the die tip.

Subsequently, the fibrous nonwoven elastic web formed as described above is stretched without applying tension, i.e., a deflection force in the machine direction (MD), and the gatherable fibrous nonwoven web as a fine fiber is manufactured by Polymontion Himont Company. PC 973) was formed on the surface of the elastic web by meltblowing the fibrous nonwoven elastic web on its top surface while maintaining its elongated length.

Meltblowing of the gatherable fibrous nonwoven polypropylene web was performed by extruding the polypropylene through a meltblowing die having 30 extrusion tubules per inch of line segment of the die tip. The diameter of the tubules was about 0.036 3 cm (0.0145 inches) and the length was about 0.283 cm (0.113 inches), respectively. Polypropylene was extruded through the tubules at a rate of about 0.38 g per minute tubing and a temperature of about 310 ° C. (590 ° F.). The extrusion pressure applied to polypropylene was measured as 29 pounds per square inch of gauge of the tubule. The die tip arrangement was adjusted to be nearly coplanar with the plane of the outer surface of the air plate forming a formation error gap on either side of the tubules. The air plates were adjusted to form two forming air gaps, one on each side of the extruded tubing, with an error gap of about 0.038 cm (0.015 inch). Forming air for meltblowing the polypropylene was fed to the air gap at a temperature of about 332 ° C. (600 ° F.) and a pressure of about 4 pounds per square inch of gauge.

The meltblown thus formed was subjected to direct meltblowing on the top surface of the fibrous nonwoven elastic web located about 40 cm (16 inches) from the die tip. Because of these treatment conditions, the viscosity of the polypropylene was about 20 poise, and polypropylene fine fibers of extremely fine diameter were formed on the surface of the elastic nonwoven elastic web.

Next, the tensile and deflection forces were reduced to shrink the fibrous nonwoven elastic web and the meltblown polypropylene web was gathered in the machine direction. The resulting hybrid nonwoven elastic web has an insertion layer, which is apparently created by entanglement of the individual fibers of the two webs, since the webs are not otherwise joined by adhesive or heat bonding.

Subsequently, a sample of the fibrous nonwoven elastic web itself and a sample of the hybrid nonwoven elastic web were stretched by an Instron tensile tester, Model 1122, which stretched each sample to 100%, ie, twice its unstretched length, and then The sample was returned to an unextended state. This procedure was then repeated three times and each sample was stretched and ruptured. Each sample was about 5.0 cm (2 inches) wide, about 12.5 cm (5 inches) long, and the initial jwaw separation interval in the test was fixed at about 2.5 cm (1 inch). The samples were placed longitudinally in the tester and stretched at a rate of about 5 inches (12.5 cm) per minute. Machine direction data was obtained from a sample having a machine direction length of about 12.5 cm (5 inches) and a transverse width of about 5.0 cm (2 inches).

The transverse or cross-machine direction measurements were obtained from samples of about 12.5 cm (5 inches) in length in the transverse direction and about 5.0 cm (2 inches) in width in the machine direction. The data obtained from the fibrous nonwoven elastic web is shown in Table 3 below, and the data obtained for the hybrid elastic web is shown in Table 4 below.

TABLE 3

Fibrous nonwoven elastic web

TABLE 3a

Transverse measurement

TABLE 4

Hybrid Nonwoven Elastic Web

TABLE 4a

Transverse measurement

Tables 3 and 4 above show the total energy absorbed in pounds and pounds obtained during each repeat test and the maximum load in pounds, and when the sample is stretched in each repeat test and sample for the 100% elongation process. Each maximum elongation in inches is described. The total energy required to stretch the sample 100% in the machine direction at maximum load at this stretch is about the same for the fibrous nonwoven elastic web and the hybrid nonwoven elastic web. This is foreseeable because the meltblown polypropylene web is gathered in the machine direction and generally requires less energy to stretch in the machine direction. When stretched for fracture testing, the maximum load of the hybrid nonwoven elastic web increased by about 70% or more, indicating that the meltblown polypropylene web contributed to the strength of the hybrid nonwoven elastic web.

In the transverse machine direction (TD) where the meltblown polypropylene is not gathered, the maximum load on the initial stretch of the hybrid nonwoven elastic web is at least 60% greater than the maximum load of the fibrous nonwoven elastic web. This indicates that the meltblown polypropylene web contributes to the strength of the hybrid nonwoven elastic web even at low elongation. In addition, the maximum total energy absorbed for the hybrid nonwoven elastic web shows a 50% increase over that of the fibrous nonwoven elastic web with respect to the initial elongation, which then actually decreases at the next elongation. This indicates that the meltblown polypropylene web is substantially ruptured during the initial elongation and no longer contributes to the total energy of the hybrid web.

The inventors found that the tubing function of the hybrid nonwoven elastic web was still good when compared to the tubing function of the fibrous nonwoven elastic web. In addition, due to the thin web of meltblown polypropylene fine fibers adhering to the surface of the fibrous nonwoven elastic web, the hybrid web had greater water repellency due to the water repellent properties of the polypropylene. In addition, attaching a thin web of meltblown fine fibers to the surface of the meltblown nonwoven elastic web gently changed the rubbery feel of the fibrous nonwoven elastic web, thereby providing a satisfactory touch.

Example 2

60% by weight of the ABA ′ block copolymer with polystyrene “A” and “A” end blocks and poly (ethylene-butylene) “B” midblock (trade name KRATON GX 1657 from Shell Chemical Company) and polyethylene silver (USI Chemical) A blend of 40 wt% of the company's trade name PE Na 601) was meltblended to provide a preformed fibrous nonwoven web in roll-up form.

Pretreatment meltblowing of the fibrous nonwoven elastic web was performed by extruding the mixture of materials through a meltblowing die with 30 extrusion tubing per inch of line segment of the die tip. These capillaries were about 0.0363 cm (0.0145 inches) in diameter and about 0.283 cm (0.113 inches) in length. The mixture was extruded through the tubules at a rate of about 299 ° C. (570 ° F.) at a rate of about 0.5 g per minute tubing per minute. The extrusion pressure applied to this mixture was measured as 144 pounds per square inch of gauge of the customs. However, this measurement is considered inaccurate due to incomplete pressure probes. The die tip arrangement was adjusted to retract about 0.275 cm (0.110 inches) inward from the plane of the outer surface of the air plate forming the forming air gap on either side of the tubule. The air plates were adjusted to form two forming air gaps, one on each side of the extruded tubing, with a gap of about 0.275 cm (0.110 inch). Forming air for meltblowing the mixture was fed to the air gap at a temperature of about 329 ° C. (614 ° F.) and a pressure of about 4 pounds per square inch of gauge. Meltblown fine fibers were formed on a forming screen that was about 40 cm (16 inches) away from the die tip. However, the measurement of this distance was not actually performed.

Subsequently, the fibrous nonwoven elastic web formed as described above is stretched without being applied by tension, that is, a deflection force in the machine direction (MD), and the gatherable fibrous nonwoven web is made of polypropylene as a fine fiber (trade name PF 301 of Himont Company). ) Was formed on the surface of the elastic web by melt blowing on the top surface of the fibrous nonwoven elastic web while keeping the fibrous nonwoven elastic web at its elongated length.

Meltblowing of the gatherable fibrous nonwoven polypropylene web was performed by extruding the polypropylene through a meltblowing die having 30 extrusion tubules per inch of line segment of the die tip. The diameter of the tubules was about 0.0363 cm (0.0145 inches) each and about 0.283 cm (0.113 inches) long. Polypropylene was extruded through the tubules at a rate of about 0.75 g per minute capillary at a temperature of about 310 ° C. (590 ° F.). The extrusion pressure applied to the polypropylene was measured as about 186 pounds per square inch of gauge of the tubing. The die tip arrangement was adjusted to extend about 0.025 cm (0.010 inches) past the plane of the outer surface of the air plate forming the forming air gap on either side of the tubules. The air plate was adjusted to form two forming air gaps, one on each side of the extruded capillary, with an error gap of about 0.450 cm (0.018 inch). Forming air for meltblowing the polypropylene was fed to the air gap at a temperature of about 332 ° C. (600 ° F.) and a pressure of about 2 pounds per square inch of gauge. The distance between the die tip and the surface of the fibrous nonwoven elastic web forming a gatherable polypropylene web thereon was about 25.4 cm (10 inches). Because of these treatment conditions, the viscosity of the polypropylene was about 124 poise, and larger diameter meltblown polypropylene fine fibers formed on the surface of the elongated fibrous nonwoven elastic web.

Next, the tensile and deflection forces were reduced to shrink the fibrous nonwoven elastic web and the meltblown polypropylene web was gathered in the machine direction. The resulting hybrid nonwoven elastic web has an insertion layer, which is apparently produced by entanglement of the individual fibers of the two webs, since the webs are not otherwise joined by adhesive or heat bonding.

Subsequently, a sample of the fibrous nonwoven elastic web itself and a sample of the hybrid nonwoven elastic web were stretched by an Instron tensile tester, Model 1122, which stretched each sample 100%, i.e., twice its unstretched length. Then, the sample was returned to an unextended state. This procedure was then repeated three times and each sample was stretched and ruptured. Each sample was about 5.0 cm (2 inches) wide, about 12.5 cm (5 inches) long, and the initial jaw separation interval in the tester was fixed at about 2.5 cm (1 inch). The samples were placed longitudinally in the tester and stretched at a rate of about 5 inches (12.5 cm) per minute. Machine direction data was obtained from a sample having a machine direction length of about 12.5 cm (5 inches) and a transverse width of about 5.0 cm (2 inches). Transverse or cross-machine direction measurements were obtained from samples with a transverse length of about 12.5 cm (5 inches) and a machine direction width of about 5.0 cm (2 inches). The data obtained for the hybrid nonwoven elastic web formed by Example 2 is shown in Table 5 below.

Table 5 shows 100% elongation, which requires a small amount of energy or load in the machine direction, while the total energy absorbed increases by about 7 times when the hybrid is stretched and ruptured in the machine direction, and the peak load is about 3 It indicates a doubling. In the transverse direction without gathering the meltblown, it initially absorbed about 3.5 times the total energy absorbed by the total energy absorbed in order to rupture at 100% elongation, and then the energy corresponding to any of the next 100% elongation. Corresponded to about 4 to 5 times. In addition, the maximum load on the first extension in the transverse direction was at least about 40% higher than the maximum load on any subsequent extension in the transverse direction, including rupture elongation.

TABLE 5

Hybrid Nonwoven Elastic Web

TABLE 5a

Transverse measurement

Comments in Tables 3, 4, and 5

* = Total energy absorbed

** = average

*** = standard deviation

The average value of the measurement of **** = 2, the value of 3,376 for the third measurement maximum TEA, 1.232 for the maximum load, and 5,609 for the tooth extension were obtained. These numbers are considered inaccurate because they deviate too much from the other two measurements.

Unless otherwise stated, the data shown in Tables 3, 4 and 5 above represent the average obtained by five individual measurements for each machine direction measurement and three individual measurements for each lateral direction measurement.

The basis weight of the meltblown fibrous nonwoven elastic web used in Example 1 was 67.3 g per square meter, and the basis weight of the gatherable meltblown polypropylene web formed on the surface of the fibrous nonwoven elastic web of Example 1 was 12.2 g per square meter. Was measured. The relaxation or shrinkage of the hybrid nonwoven elastic web of Example 1 was about 54%. This looseness of the composite is obtained by taking a sample of the composite about 10.0 cm (4 inches) in length in the machine direction, until the resistance to elongation by the gathered polypropylene web, ie wrinkles in the polypropylene web. The sample is stretched in the machine direction until removed. At this time, it was extended to about 10 cm (4.0 inches).

The basis weight of the fibrous nonwoven elastic web used in Example 2 was about 66.2 g per square meter, and in Example 2 the basis weight of the fibrous nonwoven gatherable polypropylene web melted on the surface of the elastic web per square meter It was about 21.4 g. The relaxation or shrinkage of the hybrid nonwoven elastic web of Example 2 was determined to be about 42%. This looseness takes about 30 cm (12 inches) of composite material in the relaxed length in the machine direction and until the resistance of elongation by the gathered polypropylene develops, i.e. until the gathering of the polypropylene web is removed. The sample was measured by stretching in the machine direction. At this time, a sample of about 30 cm (12 inches) extended to about 51.75 cm (20.7 inches).

When observing a relaxed, shrunk hybrid nonwoven elastic web, the meltblown polypropylene web exhibited a creped, gathered appearance, wherein the segments of creping or gathering generally melted on the surface of the fibrous nonwoven elastic web. It is transverse to the direction in which the fibrous nonwoven elastic web is stretched (ie transverse to the machine direction) during the formation of the new polypropylene web. Interestingly, it has also been observed that fibrous nonwoven elastic webs of shrinking and relaxed hybrid nonwoven elastic webs exhibit lines of creping or gathering, where the lines of creping or gathering are incorporated into the meltblown polypropylene It was parallel to the stretching direction of the fibrous nonwoven elastic web during the formation of (ie the creping or gathering line of the fibrous nonwoven elastic web was generally parallel to the machine direction). Thus, the two webbing hybrids comprise a web with alternating lines of gathering or creping, which lines generally cross each other at right angles. The formation of gathering or creping lines in the gatherable fibrous nonwoven polypropylene is expected in light of the gathering of this web in the machine direction. Such formation of gathering or creping lines in a fibrous nonwoven elastic web and in particular in the fibrous nonwoven elastic web generally perpendicular to the gathering or creping line of the gatherable fibrous nonwoven polypropylene is unpredictable. It was.

A portion of the hybrid nonwoven elastic web having a machine direction (MD) length of about 14.7 cm (5 7/8 inches) and a transverse (TD) length of about 11.25 cm (4 1/2 inches) is cut from the hybrid nonwoven elastic web. The Gathered Fibrous Nonwoven Meltblown Polypropylene Web was separated from the fibrous elastic web. After separating the gathered fibrous nonwoven meltblown polypropylene web from the fibrous nonwoven elastic web, the gathered fibrous nonwoven meltblown polypropylene web is relaxed to a size of about 17.5 cm (7 inches) in the machine direction and its transverse direction. Was observed to have about 11.25 cm (4 1/2 inches). Importantly, the web nonwoven gathered web substantially retained its creped or gathered arrangement in the machine direction. Moreover, the separated gathered polypropylene webs could be stretched in the machine direction after applying tension and deflection forces in the machine direction, and, when the tension and deflection forces were removed, their relaxation, deflection, and unstretched gathered size [about 17.5 cm (7 inches) × about 11.25 cm (4 1/2 inches)], ie substantially contracted. For example, after stretching approximately 17.5 cm (7 inches) × about 11.25 cm (4 1/2 inches) of a gathered fibrous nonwoven polypropylene web in the machine direction (MD) to the extent that the gathers are substantially straight The sample was measured to find that the machine direction (MD) length was about 23.75 cm (9 1/2 inches) and the transverse direction (TD) size was about 11.25 cm (4 1/2 inches).

When the stretching and deflection forces were removed from the sample, the sample was less than one minute in size in the machine direction (MD) of about 17.5 cm (8 inches) and in the transverse direction (TD) of about 11.25 cm (4 1/2 inches). Returned to size. After repeating the stretching process, the sample was about 23.75 cm (9 1/2 inches) long in the machine direction (MD) and about 11.25 cm (4 1/2 inches) in the transverse direction (TD). appear. After finishing the application of the second extension and extension force, the polypropylene web was about 17.6 cm (7 1/16 inch) in the machine direction (MD) and about 11.25 cm (4) in the transverse direction (TD) within 1 minute. Half inch). This result was unpredictable because it was believed that PF 301 polypropylene did not have elastic properties.

Other variations of the method of the invention and of the product formed by the method are possible. For example, two or more gatherable fibrous nonwoven webs 50 may be glued on top of another in a stacked arrangement to provide additional thickness to the gatherable fibrous nonwoven web 50. Secondly, the gatherable fibrous nonwoven web 50 is separated or otherwise bonded to both sides of the fibrous nonwoven elastic web 22 in other manners described herein, such that the following three web sequences, namely, a gatherable fibrous nonwoven web, are provided. It is possible to form a hybrid nonwoven elastic web having a fibrous nonwoven elastic web / gatherable fibrous nonwoven web.

The three web sequences in which the fibrous nonwoven elastic web is inserted between two gatherable fibrous nonwoven webs are particularly bonded when the nonwoven elastic web 22 is formed from an adhesive elastomeric material as described above, for two reasons. This is because the insertion of the adhesive elastic web 22 between the webs prevents the adhesive web 22 from attaching to other portions of the web 52 when rolling up the web 52 for storage. The three web materials can be formed in a manner as schematically shown in FIG. This method is the same as the one shown schematically in FIG. 1 until the two layered composite nonwoven elastic web 52 exits the rollers 40 and 42. Thereafter, instead of treating the nip or gap 54 between the rollers 56 and 58, the hybrid web 52 is moved to the nip or gap 78 between the rotary roller 80 and the rotary roller 82. ).

The hybrid web 52 was then conveyed by a third porous focusing screen 84 to the nip or gap 86 between the rotary nip roller 88 and the rotary roller 90. The porous focusing screen 84 is moved and operated around rollers 80 and 82 in the direction indicated by arrow 92 in FIG. Adjust the rotation of the rollers 80, 82, 88 and 90 to adjust the surface circumferential speeds of the rollers 80, 82, 88 and 90 to the rollers 40 and 44 It was made to be the same as the surface circumferential speed of. Thus, the fibrous nonwoven elastic web 22 was kept at its elongated and flattened length as was done by the porous focusing screen 84.

While the hybrid nonwoven elastic web 52 is transported by the porous focusing screen 84, the conventional meltblowing die 94 (which may utilize a conventional spunbonding die or carding device, if necessary) is fine. The fibers 98 were meltblown directly on the stretched top surface of the nonwoven elastic web 22 to form a second gatherable nonwoven web 96 on the other surface of the stretched fibrous nonwoven elastic web 22. Materials that can be used to form the gatherable second web 96 can include any of the same materials as those described above that can be used to form the gatherable first fibrous nonwoven web 50. . Fine materials may also be incorporated into the web 96 as described above with respect to the webs 22 and 50. Thereafter, the gatherable second fibrous nonwoven web 96 is essentially heat-bonded to the fibrous nonwoven elastic web 22 by the action of rollers 88 and 90, such as rollers 40, 44. Can be. The heat bonding of the second fibrous nonwoven web 96 gatherable to the fibrous nonwoven elastic web 22 is described above in connection with the heat bonding of the first gatherable fibrous nonwoven web 90 to the fibrous nonwoven elastic web 22. It can carry out in the same temperature range as the bar, and the same pressure range. If desired, conventional sonic bonding techniques (not shown) can be used in place of the heat bonding step. Alternatively, if the fibrous nonwoven elastic web 22 is adhesive, it will not be necessary to heat-bond the gatherable fibrous nonwoven web 96 to the fibrous nonwoven elastic web, as described above, because the gatherable agent This is because the two fibrous nonwoven webs 96 are simultaneously formed on the surface of the fibrous nonwoven elastic web 22 and are joined.

In another example, when the separation of the gatherable web 96 from the elastic web 22 is performed in a later step, the gatherable second fibrous nonwoven web 96 forms the web 96 on the surface of the web 22. While the individual fibers of the web 96 can be entangled with the individual fibers of the web 22, they can be detachably bonded to the surface of the fibrous nonwoven elastic web 22. In this example, the gatherable fibrous nonwoven web 96 can be formed on the fibrous nonwoven elastic web 22 simultaneously and joined.

In these examples, an improved method of bonding the webs 50 and 96 to the web 22 is to provide the elastic web 22 prior to forming the webs 50 and 96 on the elongated surface of the web 22. It can carry out by apply | coating an adhesive material to the surface of. Use of such an adhesive coating agent on the surface of the web 22 can be easily performed by the nip rollers 32 and 82 by the conventional method. For example, the adhesive material may be applied to the surfaces of the rollers 32 and 82 in a conventional manner such that the rollers 32 and 82 pass through the nips 28 and 78 through the web 22. In doing so, the adhesive is transported to the surface of the web 22. Alternatively, the adhesive can be applied to the surface of the web 22 in an array of spots.

After bonding the gatherable web 96 to the elastic web 22, the deflection force on the web 22 is applied between the three webbing hybrids 100 between the two rotary nip rollers 104 and 106. Relax by passing through nip or gap 102. Adjust the rotation of the rollers 104 and 106 so that the hybrid web 100 is relaxed by the surface circumferential speeds of the rollers 104 and 106, and, due to their elastic properties, their relaxation, unbiased length To shrink. By relaxing and retracting the web 100 to its relaxed, unbiased length, the fibrous nonwoven elastic web 22 is relaxed and retracted to gather both the gatherable fibrous nonwoven webs 50 and 96. Finally, the hybrid web 100 can be wound and stored as shown at 108. Since the adhesive elastic web 22 has been inserted between the webs 50 and 96, the adhesive elastic web does not adhere to other portions of the hybrid web 100 during storage. This material can be used to form a variety of materials, such as diaper products and the like.

The three webbing hybrids 100 as described above with respect to the adhesive nonwoven inertia web 22 can be formed without the use of an adhesive material to form the web 22. In this case, other methods for bonding the web 96 to the web 22 may be used, such as fiber entanglement, heat bonding, or sonic bonding.

Another variant of the invention is to gather one or more gatherable webs 50 and 96 in the transverse machine direction TD opposite the machine direction MD as shown in the accompanying figures. If it is necessary to gather the gatherable web 50 and / or 96 in the transverse machine direction TD, secondary devices for stretching and contracting the elastic web 22 in the transverse direction may be used. For example, FIG. 4 illustrates another embodiment of the present invention, wherein the gathered nonwoven elastic web 50 of the example shown in FIG. 1 is formed on the stretched, stretched surface of the nonwoven elastic web 22. Avoided. In the example of FIG. 4, the gathered nonwoven elastic web 50 is formed directly on the surface of the porous forming screen 110, which itself is the direction of machine movement as indicated by arrow 112. By elongation and contraction. For example, the stretchable and retractable porous focusing screen 110 may be formed from a continuous web of nonwoven elastic web 22. Alternatively, the porous focusing screen 110, which can be stretched and shrunk, can be formed from the wire mesh screen 114 shown approximately in FIG. Wire mesh screen 114 may be formed from a plurality of substantially parallel springs 116 wound and stretched in the machine direction MD, which parallel springs 116 extend in the transverse machine direction TD. Which are connected to each other in the transverse machine direction TD by a plurality of thin, generally parallel wires 118. The transverse wires 118 are arranged in close proximity to one another so that the transverse wires 118 contact each other when the wire mesh screens 114 are in an unbiased, relaxed or retracted arrangement. After applying tension or deflection forces in the machine direction, the wound spring 116 can elongate, i.e., stretch in the machine direction, and the thin transverse wires 118 separate from each other to form the porous focusing surface 110. Thus, the deflection, extension, and stretched arrangements are shown in FIG.

Alternatively, the wire mesh screen 114 can be formed from a plurality of substantially parallel springs wound and stretched in the transverse machine direction, which springs are thin, generally parallel, extending in the machine direction MD. The plurality of wires are connected to each other in the machine direction MD. This arrangement can be explained by rotating FIGS. 5 and 6 by 90 °, so that the gatherable web 96 in the transverse machine direction TD against the machine direction MD as shown in the accompanying figures. You have an array that can be gathered. If gathering of the transversely gatherable web 96 is desired, the screening 114 may be replaced with a secondary conventional device (not shown) for stretching and contracting the screening 114 in the transverse direction. The device shown in the accompanying drawings may be substituted for stretching and retracting in the machine direction MD.

In FIG. 4, the movement of the stretchable and retractable porous focusing screen 110 in the machine direction 112 is applied to the rollers 120 and 122 operated by conventional actuators (not shown). It is performed by the screen-in 110 is operated by. In addition, although not shown in the drawings for the sake of brevity, a conventional vacuum box is placed between the rollers 120 and 122 and below the bottom surface of the upper portion of the screen 110. The vacuum box assists in the retention of the web 22 on the top surface of the screen 110. The stretchable and retractable porous focusing screen 110 is passed through a nip 124 between a pair of rotating nip rollers 126 and 128. The nip 124 is adjusted to rigidly couple the rollers 126 and 128 with the porous connecting screen without adversely affecting the stretchable, stretchable porous focusing screen 110. The rotation of the rollers 126 and 128 is adjusted to make the surface circumferential speeds of the rollers 126 and 128 substantially the same as the surface circumferential speeds of the rollers 120 and 122. The stretchable and stretchable or deflatable porous focusing screen 110 also allows this pair of rotating nip rollers 132 and 134 to affect the porous focusing screen 110 without adversely affecting the porous focusing screen 110. It is firmly coupled to the Cree (110). The rotation of the rollers 132 and 134 is adjusted to make the surface circumferential speeds of the rollers 132 and 134 larger than the surface circumferential speeds of the rollers 120 and 122.

As a result of the increase in the surface circumferential speeds of the rollers 132 and 134 with respect to the surface circumferential speeds of the rollers 120 and 122, it is possible to extend and contract the deflection or stretching force in the longitudinal or machine direction (MD). It is applied to the porous focusing screen 110 and the screen 110 is elongated in the longitudinal direction in the zone 136, the length is deflected. The elongation of the porous focusing screen 110 occurring in the zone 136 between the rollers 126 and 128 and the rollers 132 and 134 is, for example, the surface of the rollers 126 and 128. The surface circumferential speeds of the rollers 132 and 134 can be varied with respect to the circumferential speed. For example, when the surface circumferential speeds of the rollers 132 and 134 are about twice the surface circumferential speeds of the rollers 126 and 128, the stretchable and stretchable porous focusing screen 110 may be substantially About twice as long, the deflected length, ie about 200% of its stretch, undeflected length. The stretchable and stretchable porous focusing screen 110 is suitably stretched in zone 136 to a length that corresponds to at least about 125% of its shrinkage, unbiased and unstretched length. In particular, it is suitable for the screenin 110 to elongate from the elongated length in the zone 136, ie 150% of its contraction, unbiased and unextended length. More specifically, the porous focusing surface 110 is at least about 150% of the stretched, undeflected and unstretched length of the porous focusing surface 110 to the stretched, undeflected and unstretched of the porous focusing surface 110. Stretching to an elongated length of at least 700% of the length is suitable.

While the stretchable and stretchable porous focusing screen 110 is in an elongated arrangement in the zone 136, the meltblowing microfibers 138 formed by the conventional meltblowing die 140 are transferred to the porous focusing screen. Meltblowing the stretched surface of (110). When the melt blowing microfibers 138 are deposited on the stretched porous focusing screen 110, these microfibers are entangled and glued together to form a gatherable adhesive fiber nonwoven web 96. The entangled gatherable adhesive fibrous nonwoven web 96 is conveyed by the porous focusing screen 110 through the nip 130 onto the nip 142 formed between the rotary roller 120 and the rotary nip roller 144. Let's do it. The surface circumferential speed of the rotary nip roller 144 is adjusted to make it substantially equal to the surface circumferential speeds of the rotary roller 120 and the rollers 122, 126, and 128. Since the surface circumferential speeds of the rollers 144 and 120 are substantially the same as the surface circumferential speeds of the rollers 122, 126, and 128, the stretching force is removed from the elongated porous focusing screen 110. Then, the screen 110 is stretched, and the screen is contracted to its contracted and unbiased length as a result of its shrinkable properties. The porous focusing screen 110 is relaxed and shrunk to its contracted, unbiased length to obtain a gatherable fibrous nonwoven web 96, which is formed on the surface of the web screen 110 while 110 is maintained in its stretched arrangement, stretched to gather on the top surface of the stretched porous focus screen 110. Thus, gathering of the gatherable fibrous nonwoven web 96 takes place in the band 146 between each pair of rollers 132 and 134 and 120 and 144.

After stretching and shrinking the porous focusing screen 110, the gatherable fibrous nonwoven web 96 may be wound on the feed roller 148 for storage and shipping. For this reason, the rotational speed of the feed roller 148 is controlled to store the gathered fiber nonwoven 96 in a substantially untensioned state. This can be done by adjusting the rotational speed of the roller 148 to make the surface circumferential speed of the roller 148 substantially equal to or slightly larger than the surface circumferential speeds of the rollers 120 and 144.

In the case of forming a three-layer hybrid web, it is preferable to separate the two outer gathered nonwoven webs from the elastic nonwoven web, as shown in FIG. If this is the case, the fibrous nonwoven gather webs 50 and 96 are separated from the fibrous nonwoven elastic webs 22, which separates the web 50 between two rotating nip rollers 152 and 154. Pass through nip 150 and pass web 96 through nip 156 between two rotating nip rollers 158 and 160. The webs 50 and 96 were then wound up for storage and then used on their respective storage rollers 162 and 164. For the reasons described above, the gathered nonwoven webs 50 and 96 are wound such that the webs 50 and 96 are stored in an untensioned or substantially untensioned form on the rollers 162 and 164. Be careful in This rotates the rollers 162 and 164 to make the surface circumferential speed of the roller 162 equal to or slightly larger than the surface circumferential speed of the rollers 152 and 154, and to increase the surface circumferential speed of the roller 164. Make it equal to or slightly larger than the surface circumferential speeds of the rollers 158 and 160. After separating the webs 50 and 96, the fibrous nonwoven elastic web 22 is passed through a nip 166 between the two rotating nip rollers 168 and 170 and onto the storage roller 172. Wind up.

In the particular examples described herein it is customary to form the gatherable fibrous nonwoven webs 50 and 96 using conventional meltblowing dies and meltblowing methods, but conventional spunbonding dies or spunbonding The method may be used in place of meltblowing dies and methods, and the scope of the present invention uses spunbonding dies or methods or other devices instead of meltblowing dies and methods 48 and 94 to form a gatherable nonwoven web. It also includes materials formed by. If any or both of the meltblowing dies or methods 48 and 94 are replaced by spunbonding dies and methods, the webs 50 gatherable to the fibrous nonwoven elastic webs 22 and, if desired (96) The bonding of, is, as described above, inter-web adhesion (when using an adhesive elastomeric material to form the web 22), heat bonding, sonic bonding, and / or a web (on) Before forming 50) and 96, the surface of the web 22 must be used with an adhesive. Bonding of these methods utilizes a spunbonded gatherable web because the fibers of the spunbonded gatherable web are not easily entangled with the fibers of the web 22. When the joining of one or more webs 50 and 96 to the web 22 is by heat-bonding [whether the webs 50 and 96 are spunbonded, meltblown or formed by other methods Whether or not], care should be taken to ensure that the web 22 is not stretched immediately after the actual heat-bonding process has occurred and does not substantially relax and contract in an unbiased state or arrangement, since the nonwoven elastic web 22 ) Loses its elasticity while it remains above its softening point for a significant period of time. This loss of elasticity results from the fixing of the cooling elastic web 22, while having the elongated arrangement when the web is heat-bonded and held in the elongated arrangement for a period of time.

Claims (24)

Providing a nonwoven elastic web, elongating the nonwoven elastic web, forming a gatherable fibrous nonwoven web directly on the surface of the elongated nonwoven elastic web, and forming the elongated gatherable fibrous nonwoven web into the elongated nonwoven web. A method for producing a hybrid nonwoven elastic web, wherein the nonwoven elastic web is bonded to a gathered fibrous nonwoven web, wherein the nonwoven elastic web is bonded to the elastic web to gather the hybrid nonwoven web. The method of claim 1, wherein providing the nonwoven elastic web is to form a fibrous nonwoven elastic web of meltblown fine fibers. The method of claim 1, wherein providing the nonwoven elastic web is to provide a perforated elastic film. The method of claim 2, wherein the fibrous nonwoven elastic web is stretched to at least about 125% to about 700% of the relaxed length of the fibrous nonwoven web. The method of claim 1, wherein forming the gatherable fibrous nonwoven web consists of forming a gatherable fibrous nonwoven web of meltblown fine fibers. 2. The method of claim 1, wherein forming the gatherable fibrous nonwoven web is to form a gatherable fibrous nonwoven web of spunbonded fine fibers. The method of claim 1, wherein forming the gatherable fibrous nonwoven web is to form a carded web. The method of claim 1, wherein joining the gatherable fibrous nonwoven web to the nonwoven elastic web is by a method of heat bonding. The method of claim 8, wherein the step of heat-bonding the gatherable fibrous nonwoven web to the nonwoven elastic web is used to form about 50 ° C. or less of the melting point of the material used to form one of the webs or one of the foregoing webs. Heat-bonding within a temperature range up to near the melting point of the material. Providing a tacky nonwoven elastic web, elongating the tacky nonwoven elastic web, forming a gatherable fibrous nonwoven web directly on the surface of the elongated nonwoven elastic web and at the same time the gatherable nonwoven elastic web on the surface of the elongated nonwoven elastic web. While the webs are bonded and a gatherable fibrous nonwoven web is formed on the surface of the stretched fibrous nonwoven elastic web, the two elastic webs are bonded to each other to allow the adhesive nonwoven elastic web to adhere to the gatherable fibrous nonwoven web so that the hybrid elastic nonwoven is Forming a web, and relaxing the adhesive hybrid nonwoven elastic web to gather the gatherable fibrous nonwoven web, wherein the nonwoven elastic elastic web is joined to the gathered fibrous nonwoven web. Manufacturing method. The method of claim 10, wherein providing the tacky nonwoven elastic web is to form a nonwoven elastic web of meltblown fine fibers. 11. The method of claim 10, wherein forming the gatherable fibrous nonwoven web comprises forming a gatherable fibrous nonwoven web of meltblown fine fibers on a surface of the fibrous nonwoven elastic web. The method of claim 10, wherein forming the gatherable fibrous nonwoven web comprises forming a gatherable fibrous nonwoven web of fine fibers spunbonded to a surface of the fibrous nonwoven web. Providing a nonwoven elastic web, elongating the nonwoven elastic web, forming a gatherable fibrous fibrous web directly on the surface of the stretched nonwoven elastic web and simultaneously forming a gatherable fibrous nonwoven web on the surface of the stretched nonwoven elastic web And entangle the individual fibers of the gatherable nonwoven web with the individual fibers of the nonwoven elastic web to bond the nonwoven elastic web to the gatherable nonwoven web to form a hybrid nonwoven elastic web, and A method for producing a hybrid nonwoven elastic web, wherein the nonwoven elastic web is bonded to a gathered fibrous nonwoven web, wherein the elastic web is relaxed to gather the gatherable fibrous nonwoven web. The method of claim 14, wherein providing the nonwoven elastic web is to form a fibrous nonwoven elastic web of meltblown fine fibers. 15. The method of claim 14, wherein the bonding is performed by simply intertwining individual fibers of the gatherable fibrous nonwoven web with individual fibers of the fibrous nonwoven elastic web of meltblown fine fibers. 15. The method of claim 14, wherein providing the nonwoven elastic web is to provide a perforated nonwoven elastic film. 15. The method of claim 14, wherein the bonding is performed by simply intertwining individual fibers of the gatherable fibrous nonwoven web with the perforation of the perforated nonwoven elastic film. Providing a stretchable and retractable formed surface, stretching the formed surface, and forming a gatherable fibrous nonwoven web directly on the stretched forming surface to detachably bond the gatherable fibrous nonwoven web to the stretched forming surface. And shrinking the formed surface to gather the gatherable fibrous nonwoven web and to separate the gathered fibrous nonwoven web from the shrunk forming surface. The method of claim 19, wherein the fibrous nonwoven elastic web is stretched by at least about 125% to about 700%. 20. The method of claim 19, wherein forming the gatherable fibrous nonwoven web is to form a gatherable fibrous nonwoven web of meltblown and fine fibers. 20. The method of claim 19, wherein forming the gatherable fibrous nonwoven web comprises forming a gatherable fibrous nonwoven web of spunbonded fine fibers. Providing a formed surface of a nonwoven elastic web having a relaxed, unbiased, contracted length and a stretched, biased, and extended length, elongating the nonwoven elastic web forming surface to the extended length, Forming a gatherable fibrous nonwoven web directly on the forming surface of the nonwoven elastic web, wherein the gatherable fibrous nonwoven web is separated from the nonwoven elastic web forming surface, with the elastic web held at an elongated length. And possibly separable, the separable bonding of the fibrous nonwoven web to the nonwoven elastic web forming surface is such that the individual fibers of the gatherable nonwoven web are formed while the gatherable fibrous nonwoven web is formed on the surface of the nonwoven elastic web forming surface. Are made by entangling with the individual fibers of the fiber nonwoven elastic web forming surface The step of shrinking by the step, the nonwoven elastic web forming surface gathering the gathering available fibrous nonwoven web. And separating the nonwoven elastic web from the nonwoven elastic web forming surface to gather the gatherable fibrous nonwoven web. 24. The method of claim 23, wherein providing the nonwoven elastic web forming surface results in forming a nonwoven elastic web of meltblown fine fibers.

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