DE602005004234T2 - Stretchable nonwovens - Google Patents

Abstract

A nonwoven material which can be elongated and which will partially recover. The material comprises a web of fibers comprising polymeric chains which fibers are entangled with one another. The fibers are stretched in a first direction at a temperature wherein the fibers are aligned in a first direction and the polymeric chains within the fiber are also orientated in such first direction. The fibers are then cooled and demonstrate an ability to elongate and partially recover in a second direction that is different from the first direction.

Description

THE iNVENTION field

The The present invention relates to a method for producing a Nonwoven fabric that can be made to stretch and retire can. The processes for making such stretchable nonwoven fabrics have a special utility in terms of more consistent Multicomponent filaments with a denier of 0.01 to 1.0 dtex, and that are connected.

Background of the invention

nonwovens be in a big one Bandwidth used by applications such as medical devices, Hygiene products, work clothing, sports and leisure clothing, footwear, bed linen and in the construction of carpets. These types of substances differ woven or knitted fabrics, insofar as they are made directly from individual fibers are produced, which form a fiber mat in an irregular pattern on top of each other be laid, what the conventional Textile production processes of multi-stage yarn preparation and weaving or knitting. the entanglement of the fibers or filaments of the fabric acts to make the fabric an essential integrity level provides.

The Production of nonwovens is a sophisticated technique. In general, nonwoven webs and their manufacture include making of filaments or fibers and laying them down on a support such that causes the filaments or fibers as a mat with a desired one Overlay basic weight. The joining of such a mat may be by entanglement or otherwise, as by adhesive, application of heat and / or Pressure or, in some cases, only by pressure.

nonwovens or nets have been made in many processes, such as by melt-blowing, spun-bonding process, with carded tracks and, in younger ones Time, through melt spinning process.

At the Meltblowing, thermoplastic resin is introduced into an extruder where it is melted and heated to the appropriate temperature, the for the formation of fibers is necessary. The extruder carries that melted resin into a special meltblowing die. The nozzle arrangement generally consists of a large number of linearly arranged capillaries with a small diameter. The resin comes out of the nozzle openings as molten threads in a high-velocity gas stream, usually air. The Air dampens the polymer into a stream of fine fibers that is on a front of the Power placed moving screen to be collected. If the fibers land on the screen, they entangle themselves to form a related Net or a related one Train so that it is generally impossible a complete To remove fiber from the mass of fibers or a fiber from the fiber To track beginning to end.

The Spun-bonding process has also been used to nonwovens manufacture. There are different spun-bonding methods, though all contain the following basic steps: extrusion of continuous fibers, Quench the fibers by pulling or steaming the filaments through High speed fluid and collecting the filaments on a surface for Formation of a railway. Webs made by spun bonding can have one more pleasant surface texture exhibit as meltblown webs as they attach to the deniers from textile filaments and subsequently have a textile-like fold and handle.

While the Production of Nonwovens from Homopolymer, Single Component Filaments or fibers is well known, the use of "splittable" multicomponent fibers or filaments for some applications may be beneficial. These types of fissile fibers or filaments comprise several subcomponents, which are usually comprising two or more different polymeric materials, wherein the subcomponents side by side along the length of the Filaments or fibers are arranged. Various cross-sectional configurations are known, such as segment, island, flower arrangements or arrangements side by side, as well as a wide range of additional specific configurations.

The subcomponents of fissile fibers or filaments can be separated by various chemical or mechanical processing techniques. Parts of the multicomponent fiber or the multicomponent filament can be separated by heat, needle or water jet treatment, for example the. A suitable chemical treatment of some types of multicomponent fibers or filaments acts to dissolve portions thereof so that the subcomponents of the fibers or filaments are at least partially separated.

While woven and knitted fabrics have a handle, drape and stretchability have, opposite For most nonwovens, these benefits are gained the cost and complexity the textile manufacturing process used to produce woven and knitted fabrics are used, partly outweighed. There have been numerous attempts at stretching and retraction properties of nonwovens to benefit from the lower production costs. This includes the use of more expensive elastomeric fibers in the web, as well as the Use additional Manufacturing steps, such as lamination or coating of the Train with other materials and mechanical crimping some the fibers.

The U.S. Patent No. 4,426,420 titled "Spunlaced Fabric Containing Elastic Fibers" to DuPont is focused on the hydraulic entanglement of spun-lace fabrics that are heat treated for improved stretch properties. Two types of fibers include the hard mat fibers (polyester, polyamide, etc.) and elastomeric fibers (preferably 10-25% poly (butylene terephthalate) copoly (tetramethyleneoxy) terephthalate).

The U.S. Patent No. 4,820,572 entitled "Composite Elastomeric Polyether Block Amide Nonwoven Web" to Kimberley Clark Corp. is directed to an elastomeric nonwoven web formed by meltblowing, a coherent matrix of preferably polyester block amide copolymer microfibers.

The U.S. Patent No. 5,151,320 entitled "Hydroentangled Spunbonded Composite Fabric and Process" to Dexter Corp. is directed to a hydroentangled composite made by subjecting a spun-bonded base web material made of continuous man-made filaments to a transverse stretching step of at least 5 percent of its original extent, but extending in the transverse direction at the time of stretching less than the transverse extension of the material under ambient conditions. A cover layer of fluid-soluble fibers is applied to the stretched base sheet to form a multi-ply structure, and the hydroentangled structure is applied to bond the layers.

The U.S. Patent No. 5,227,224 entitled "Stretchable Nonwoven Fabrics and Method for Making Same" to Chisso Corp. is directed to a uniform web having 70-100% by weight of heat-bondable polypropylene composite base fibers and 0-30% of other organic fibers (polyamide, polyester) having a heat shrinkage percentage of 50% or more at 120 ° C. The fibers are uniformly entangled and "shrunk" as a result of sufficient entanglement provided by further heat treatment (not under tension), resulting in a fabric having elastic retractability at 30% elongation of 80% or more in both warp and weft. as well as shot direction has.

The U.S. Patent No. 5,540,976 entitled "Nonwoven Laminate With Cross Directional Stretch" to Kimberley-Clark Corp. is aimed at a laminate with three layers. The outer layers of spun-bonded nonwoven webs are made of crimped or crimpable fibers and the inner layer is an elastomeric polymer layer. The layers are preferably joined together by hydroentanglement.

The U.S. Patent No. 5,549,964 entitled "Stretchable Nonwoven Fabric and Method of Manufacturing the Same" to Asahi Kasei Kogyo Kabushiki Kaisha is directed to a stretchable nonwoven fabric made using a hydrogenated block copolymer. The copolymer preferably comprises a vinyl aromatic compound, a conjugated diene compound and a polyolefin, and is melt-blown.

The U.S. Patent No. 5,534,335 entitled "Nonwoven Fabric Formed From Alloy Fibers" to Kimberley-Clark Corp. is directed to a nonwoven fabric having at least two thermoplastic polymers and a compatabilizer. One of the thermoplastic polymers is in a dominant continuous phase (for example, a polypropylene) and the other is in a non-continuous phase (for example, as a polyamide or polyester). The melting temperature of the non-continuous phase polymer is preferably 30 ° C lower than the melting temperature of the continuous phase polymer. The phase can be meltblown or spun.

The U.S. Patent No. 5,814,390 entitled "Creased Nonwoven Web With Stretch and Recovery" at Kimberly-Clark Worldwide is directed to nonwovens made by folding a precursor using intermeshing rollers and heat to form the pleats. The fabric preferably comprises a precursor web of thermoplastic fibers based on a non-elastic olefin polymer.

The U.S. Patent No. 5,910,224 entitled "Method for Forming An Elastic Necked-Bonded Material" also to Kimberley-Clark Worldwide is directed to a process for making a stretchable composite by applying the elastomeric precursor to a neckable material, neck-stretching the neckable material, and heating the elastomeric Precursor, while the neckbare material is in a teased state. The precursor may comprise a latex or a thermoelastomer. The tearable material may be formed by spun-bonding or melt-blowing and preferably comprises microfibers, for example polyester, polyamide and polyolefin.

The U.S. Patent No. 5,997,989 entitled "Elastic Nonwoven Webs and Method of Making Same" to BBA Nonwovens Simpsonville Inc. is directed to a spunbonded elastic nonwoven fabric (and a method of making the same) comprising a thermoplastic thermoplastic bonded thermoplastic web Elastomers. A slot-fed spun bonding process provides a web that has an RMS retractable expansion of at least 75% (MD and CD) after being elongated by 30% of the fabric in one go.

The U.S. Patent No. 6,689,703 titled "Elastically Stretchable Nonwoven Fabric and Fabric for Making the Same" to Uni-Charm Corp. is directed to an elastically extensible nonwoven fabric having thermoplastic elastomeric filaments wherein the filaments are entangled with each other by heat and / or mechanically to form a nonwoven fabric having crimped and non-crimped regions. The ripples have a rate of 50 / cm or more. The ripples are formed by blowing hot air against an extrudate followed by blowing a warm or cold air stream (at least 20 ° C lower than the melting point of the filaments) against the filaments so that the filaments are stretched and reduced in diameter and be cooled unevenly, whereby they are at least partially crimped. The filaments are then heat or mechanically entangled to obtain the stretchable nonwoven fabric.

U.S. Patent No. 6,692,541 entitled "Method of Making Nonwoven Fabric Comprising Splittable Fibers" to Polymer Group Inc. is directed to a process in which fibers of fissionable fibers or fibers of predetermined length are formed with a variety of subcomponents by partial hydroentanglement into their subcomponents are separable. A three-dimensional image transfer device having a dotted forming surface is used to impart a distinct surface pattern or image to the precursor web during hydroentanglement. The web is preferably carded and is lapped before providing the image or pattern in the transverse direction.

The U.S. Patent No. 2003/0064650 titled "Stretchable Multiple Component Spunbond Web And A Process for Making" at DuPont is aimed at providing high levels of three-dimensional, spiral crimp using pull rolls to provide a high degree of orientation. Filaments are pulled mechanically under conditions in which the polymeric components remain substantially amorphous. The process comprises melt-spinning continuous filaments comprising at least a first and second separate melt-spinnable polymer, wherein the polymers are arranged in separate, substantially constantly positioned regions over the cross-section of the filaments in an eccentric relationship and are substantially continuous along the length of the filaments extend. The filaments are quenched, passed through a series of rollers to cure (from amorphous to semi-crystalline), tensioned, and released to form spiral crimps.

Therefore For example, what is needed is a method of providing a nonwoven fabric for extension and provision is able and opposite represents an improvement in the prior art and according to the present Invention can be easily manufactured.

A Object of the present invention is to provide a A method of producing a nonwoven fabric made of material which was processed in the spun-bonding process, and be extended can, and for example, extension values in the range of about 5 to 70%.

A particular object of the present invention is to provide a method for producing provide thermoplastic spunbonded or a composite thereof, which is hydroentangled so that it can be stretched and have stretch and pullback.

A Object of the present invention is to provide a A method of providing a spunbonded nonwoven web a web of filaments exposing a filament web, contains the filaments, which are entangled and / or interlocked with each other then in a first selected Direction at a selected Temperature is stretched in a second, from the first direction provides different stretching properties.

Brief description of the invention

• (a) Bilden einer Faserbahn mit Polymerketten, wobei die Fasern miteinander verwickelt sind, vorzugsweise durch Hydroverwicklung, wobei die Bahn eine Länge und eine Breite aufweist;
• (b) Dehnen der Fasern in eine mit der Bahnlänge zusammenfallende erste Richtung, bei einer Temperatur zum Ausrichten der Fasern in die erste Richtung und zum Ausrichten der Polymerketten in der Faser in der ersten Richtung, wobei die Breite der Bahn verringert ist; und
• (c) Abkühlen der Fasern unterhalb der Temperatur, wobei die Faserbahn eine Fähigkeit aufweist, in eine zweite Richtung über eine Breite der Bahn verlängert zu werden und wobei sich die Fasern auch zum Teil von der Verlängerung in die zweite Richtung zurückziehen können.

The present invention is directed to a method of making a nonwoven material made of spunbond material that can be extended in a selected direction, comprising the following steps:

• (a) forming a fibrous web having polymer chains wherein the fibers are entangled, preferably by hydroentanglement, the web having a length and a width;
• (b) stretching the fibers in a first direction coincident with the web length, at a temperature to align the fibers in the first direction, and to orient the polymer chains in the fiber in the first direction, the width of the web being reduced; and
• (c) cooling the fibers below the temperature, wherein the fibrous web has an ability to be elongated in a second direction across a width of the web, and wherein the fibers may also partially retract from the extension in the second direction.

The The present invention is directed to a method of providing a nonwoven material having extensible properties, wherein the polymer chains preferably have a melting point Tm and the temperature below Tm to align the fibers in the first direction and align the polymer chains in the fiber in the first direction. This is followed by cooling the fibers below the temperature, wherein the nonwoven material is in the second direction extending from the first direction can differ, extend and distance from the renewal partially retract in the second direction. Optional can this procedure the additional Step containing the web further stretched across the width of the web and wherein the nonwoven material is still in a second direction over the Extend width of the track can and from the extension partially withdraw can.

Brief description of the drawings

The Above and other objects, features and advantages of the invention be considered when considering the written description and attached drawings further apparent in which

1 Fig. 10 is an illustration of a one-step process for making the stretchable material of the present invention;

2 FIG. 3 is an illustration of a two-step process for making the stretchable material of the invention; FIG.

3 Figure 12 is a graph of fiber orientation versus orientation angle before stretching;

4 Figure 12 is a graph of fiber orientation versus orientation angle after stretching.

Detailed description of the preferred embodiments

In a first preferred embodiment The present invention is directed to a nonwoven material, the in a selected one Direction extended comprising a fiber web comprising polymer chains, wherein the fibers are entangled with each other.

Preferably, the fibrous web comprises a microfilament nonwoven fabric having a weight of 30 to 150 g / m ² and a tear strength of> 40 N / 5 cm, wherein the nonwoven fabric is made of continuous multicomponent filaments having a denier of 1.5 to 5 dtex which are melt spun, stretched and laid down directly to form a nonwoven fabric, with the continuous multicomponent filaments being cleaved to an extent of at least 80% to form continuous microfilaments with a denier of 0.01 and 1.0 dtex, and be connected.

Further preferred the universal Multicomponent filaments a continuous two-component filament comprising two polymers. The two polymers can be one Comprising polymer selected from the group consisting of polyamides, Polyolefins and mixing thereof.

In a particularly preferred embodiment, the nonwoven fabric here can be made of a material that is manufactured and sold under the brand name Evolon ^™ by the company Freudenberg Nonwovens and is characterized as a textile consisting of microfilaments. It is reportedly processed in a continuous process from polymer granules to the finished textile, during which the spinning and depositing of the filaments in the web form are preferably combined. Water jet bonding then provides the Evolon ^™ material, which consists of endless microfilaments.

With reference to 1 can the fiber web unwound and at 10 supplied to opposite rollers, at 12 preheated and at 14 are stretched, whereby a stretch in the longitudinal direction and a widthwise unrestricted shrinkage is provided. Preferably, the heating is carried out so that the polymer chain fiber web is identified as having a melting point Tm and the preheating temperature as mentioned above is at a temperature lower than Tm and preferably lower than 0.1-20.0 ° C Tm can be adjusted. In addition, the temperature of the preheating may be set at a temperature higher than Tg and below Tm with respect to the polymers having a glass transition temperature or Tg. Preferably, as shown, the fibers are oriented in the longitudinal direction and the polymer chains are also oriented in that direction.

Further, with reference to 3 the fiber orientation (% frequency) is plotted against the orientation angle before stretching, providing a view of fiber orientation distribution (FOD). With reference to 4 For example, the fiber orientation (% frequency) was provided versus the orientation angle after stretching. After comparing 3 and 4 It should be apparent that the fiber orientation after stretching is translated in the direction in which the fabric is stretched. Before stretching, the structure is relatively isotropic and after stretching the anisotropic property is seen.

With reference to 1 it can be seen that at 16 optionally an extension in the width direction can be made, wherein the width can be adjusted to a desired size, for example using a tenter. It will be apparent to those skilled in the art that a tenter will allow the fabric to stretch to its original width. In any case, the result of in 1 illustrated procedure that after quenching and winding at 18 It has been found that a fibrous web has been produced which has a capability of elongation in a second direction different from the first (longitudinal) direction, and wherein the fibers can partially retract from such elongation. In the same sense, it has been found that the ability to extend in the second direction and partially retract reaches levels of up to about 70%.

With reference to 2 a two-stage process for producing the expandable material according to the invention is shown. at 20 It can be seen that the unwinding and feeding step involves preheating and longitudinal stretching at locations 22 and 24 which follows by using rollers and heating by use of the rollers to the desired temperatures as described herein. The substance is thus at 26 quenched and wrapped and is wrapped and then unwound and at 26 fed and can be used in this form. Optionally, the output 26 as shown, after quenching and then wrapping 28 be unwound and fed so that they after passing between the rolls in the width direction to a desired width 30 after quenching and winding at 32 can be brought.

In accordance with the present invention has thus been found that a stretchable nonwoven material can be uniquely provided which is for own use in a number of applications where the benefits of nonwoven material now along with the ability such a nonwoven fabric to provide stretching and retracting properties can be used.

While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by the present invention is not limited to these particular embodiments, and thus it is intended that the subject matter of the present invention be all and all Includes equivalents falling within the scope of the appended claims. Key to the figures figure figure Stretching in length Stretching in the longitudinal direction Stretching in width Stretching in the width direction Orientation Angle (Degrees) Orientation angle (degrees) Fiber Orientation (% Freq) Fiber orientation (% Frequ.)

Claims (10)

Method of providing a nonwoven fabric, which is made of a spunbonded material and in a selected Direction extended can be, with the following steps: (a) forming a Fiber network with polymer chains, wherein the fibers entangled with each other are, preferably by hydroentanglement, wherein the network is a length and has a width; (b) stretching the fibers into one with the net length coinciding first direction at a temperature for alignment the fibers in the first direction and to align the polymer chains in the fiber in the first direction, the width of the network is reduced; and (c) cooling the fibers below the temperature; the fiber network being an ability has extended in a second direction across the width of the network and where the fibers are also partly from the extension retreat in the second direction can. The method of claim 1, wherein the polymer chains have a melting point Tm and the temperature below the Melting point Tm is. The method of claim 2 wherein the temperature is 0.1-20 ° C below the melting point Tm is. The method of claim 1, wherein the polymer chains a glass transition temperature Tg and have a melting point Tm and the temperature at or above the glass transition temperature Tg and below the melting point Tm is. The method of claim 1 or 2, wherein the fibers extend in the second direction by up to 70% and in part of it withdraw. The method of claim 1, wherein the fiber web comprises a microfilament nonwoven fabric having a weight of 30 to 150 g / m ² and a tear strength of> 40 N / 5 cm and the nonwoven fabric of continuous multicomponent filaments having a titer of 1.5 to 5 dtex, which are melt spun, stretched and laid down directly to form a nonwoven fabric, with the continuous multicomponent filaments being cleaved to an extent of at least 80% to form continuous microfilaments with a titer of 0.01 to 1; 0 dtex, and connected. The method of claim 6, wherein the continuous multicomponent filaments a continuous two-component filament comprising two polymers. The method of claim 6, wherein one of the polymers a polyester polymer and one of the polymers comprises a polymer which consists of polyamides, polyolefins and mixtures thereof existing group selected is. The method of claim 1, comprising the additional Step, taking the net over the width of the net is further stretched and being the nonwoven material still in a second direction over the width of the network is extended be and extend from the extension partially withdraw can. The method of claim 1, wherein the step of Stretching over the width of the net placing the net on a tenter includes.