JP2006138060A - Stretchable nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric capable of being elongated and recovered and capable of being simply produced. <P>SOLUTION: A material for the nonwoven fabric capable of being elongated and partially recovered is provided. The material has a web of fibers which are entangled with one another and each contain a polymer chain. The fibers are stretched at a predetermined temperature in a first direction, so that the fibers are aligned in the first direction and simultaneously the polymer chains in the fibers are orientated in the first direction. Therefore, the fibers exhibit such properties as to be elongated in a second direction different from the first direction and to be partially recovered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates generally to stretchable nonwoven fabrics, and more specifically, the manufacture of nonwoven fabrics that can be manufactured to exhibit stretch and recovery. Regarding the method. The method for producing such stretchable nonwoven fabrics is particularly suitable for application to continuous multicomponent filaments bonded with a titer of 0.01-1.0 dtex. .

  Nonwoven fabrics are used in a variety of applications such as medical products, personal care products, work clothes, sports and leisure wear, shoe lining, sheets and pillowcases and carpet materials. This type of fabric eliminates the traditional textile manufacturing process with multi-stage yarn preparation, weaving or knitting, and is inconvenient to form a fibrous mat. It differs from woven or knitted fabrics in that it is produced directly from individual fibers that are interlaid in a regular pattern. The fabric fibers or filaments are intertwined to provide a fabric having a sufficient level of integrity.

  The production of nonwoven fabrics is a highly developed art. In general, nonwoven webs and their manufacture include the steps of forming filaments or fibers and depositing them on a carrier such that the filaments or fibers overlap as a mat of desired reference weight. It is out. Such mat bonding is accomplished by means of entanglement, or means such as applying adhesive, heating or pressing, or in some cases only pressure.

  Non-woven fabrics or webs are many, such as, for example, meltblowing processes, spunbonding processes, bonded carded web processes, and more recently meltspinning processes. Formed from the method.

  In the melt spraying method, a thermoplastic resin is fed into an extruder, melted in the molding machine, and heated to an appropriate temperature required for fiber formation. The extrusion machine supplies the molten resin to a special melt spray mold. The mold apparatus is generally a plurality of linearly arranged small diameter capillaries. The resin floats from the mold as a molten thread and is introduced into a flow of high-speed gas (usually air). This air causes the polymer to be thinned into a fine fiber blast. The fine fibers are collected on a moving screen provided in front of the blast. When the fibers reach the screen, they entangle and form a cohesive web, so that it is generally impossible to remove one complete fiber from the fiber mass. There will be a state where it is impossible to trace one fiber from the start to the end.

  Spin bonding is also used to produce nonwoven fabrics. There are various spin bonding techniques, but all spin bonding methods involve extruding a continuous filament, quenching the filament, stretching or thinning the filament with a high speed fluid, and the filament on the surface The basic steps of collecting and forming a web. Spunbonded webs give a more comfortable feel than melt sprayed webs, because spunbonded webs bring the deniers of the textile filaments closer, and consequently the textiles This is because it has a drape and a hand.

  In producing nonwoven fabrics from a single polymer, single component filaments or fibers are widely known, but in some applications, multicomponent “splittable” fibers or filaments. It may be advantageous to use Such splittable fibers or filaments include a plurality of sub-components, typically two or more different polymeric materials, which are adjacent along the length of the filament or fiber. Arranged in a matching relationship. Various specific cross-sectional shapes are known, eg segmented pie, islands-in-the-sea, flower-like, adjacent array (Side-by-side arrays), and various additional specific shapes.

  The subcomponents of splittable fibers or filaments can be split by various chemical or mechanical processing techniques. For example, some of the multicomponent fibers or filaments can be divided by heat treatment, needle punching or water jet treatment. By subjecting some types of multi-component fibers or filaments to an appropriate chemical treatment, the fibers or portions of the filaments are dissolved and, therefore, the subcomponents of the fibers or filaments are at least partially degraded.

  While woven fabrics or knitted fabrics provide a pre-determined level of feel, crease and stretchability over most nonwoven fabrics, these advantages are the advantages of the technology used to produce woven or knitted fabrics. Some offset by the cost and complexity of the style manufacturing process. Many attempts have been made to improve the stretch and resiliency of nonwoven fabrics in order to enjoy the benefits of lower manufacturing costs. These attempts include the use of more expensive elastomeric fibers in the web, as well as the lamination of other materials with the web, the coating of other materials onto the web, and some of the fibers. For example, additional processing steps such as crimping have been performed.

  Patent document 1 (invention name: Spunlaced Fabric Containing Elastic Fibers), which is assigned to DuPont, relates to a hydraulically intertwined spunlaced fabric, and this spin knitted fabric. Has been heat treated to provide improved stretch properties. Hard fiber (polyester, polyamide, etc.) and rubber-elastic fiber (preferably butylene terephthalate / tetramethyleneoxyterephthalate copolymer (poly (butylene terephthalate) -co-poly- (tetramethyleneoxy) terephthalate) 10% -25% ) Constitutes a core (batt).

  Patent Document 2 (invention name: Composite Elastomeric Polyether Block Amide Nonwoven Web), which is assigned to Kimberley Clark, is formed by a solution spraying method and is made of a polyester / blockamide copolymer. Preferably, it relates to a rubber-elastic nonwoven web having a coherent matrix of ultrafine fibers.

  Patent document 3 (invention name: Hydroentangled Spunbonded Composite Fabric and Process), which is assigned to Dexter, has a base web material of continuous composite filaments spunbonded at least to the initial dimension in the transverse direction. It relates to a composite fabric that is hydroentangled by stretching by 5%, but by stretching less than the lateral elongation of the material under atmospheric conditions during stretching. A fluid-dispersible fiber cover layer is applied to the stretched base web to form a multilayer structure that is hydraulically intertwined to bond the layer (s).

  Patent Document 4 (invention name: Nonwoven Fabrics and Method For Making Same) is assigned to Chisso Corporation, and is composed of 70 to 100% by weight of a polypropylene-based heat-bondable synthetic fiber and 0 to 30% by weight. The present invention relates to a uniform web containing other organic fibers (polyamide, polyester) and having a thermal shrinkage of the web at 120 ° C. of 50% or more. The fibers are “shrinked” as a result of being uniformly intertwined (under no tension) and sufficiently intertwined through further heat treatment. This provides the fiber with an elastic recovery of 80% or more at 30% stretch in both the warp and weft directions.

  Patent Document 5 (name of invention: Nonwoven Laminate With Cross Directional Stretch) is assigned to Kimberley Clark, but relates to three-layer lamination. The outer layer of the spunbonded nonwoven fibrous web consists of crimped or crimpable fibers and the inner layer consists of a rubber-elastic polymer layer. These layers are preferably bonded together by hydraulic entanglement.

  Patent Document 6 (Invention name: Stretchable Nonwoven Fabric and Method of Manufacturing the Same), which has been transferred to Asahi Kasei Kogyo Co., Ltd., was manufactured using a hydrogenated block copolymer. The present invention relates to a stretchable nonwoven fabric. The copolymer contains a vinyl aromatic compound, a conjugated diene compound, and a polyolefin and is sprayed by dissolution.

  Patent document 7 (Title of Invention: Nonwoven Fabric Formed From Alloy Fibers) is assigned to Kimberly Clark, and relates to one containing at least two thermoplastic polymers and a compatibilizer. One of the thermoplastic polymers exists in the dominant continuous phase (eg, polypropylene) and the other thermoplastic polymer exists as a discontinuous phase (eg, polyamide or polyester). The melting point of the discontinuous phase polymer is preferably at least 30 ° C. lower than the melting point of the continuous phase polymer. The fibers are sprayed or spunbonded.

  Patent Document 8 (Created Nonwoven Web With Stretch and Recovery) is assigned to Kimberly Clark Worldwide Inc., but this invention is a precursor with interdigitated rolls. And a non-woven fabric produced by heat-setting the heel. The fabric is preferably a non-rubber elastic olefin polymer based thermoplastic fiber having a precursor web.

  Patent Document 9 (Method for Forming An Elastic Necked-Bonded Material) is also transferred to Kimberley Clark Worldwide, but it is a neckable material that can be used as a rubber elastic precursor. The invention relates to a method for producing a stretchable composite by heating a rubber elastic precursor while a squeezable material is stretched while the squeezable material is stretched. It is. The precursor may contain latex or a thermosetting elastomer. The squeezable material can be formed by a spunbonding method or a melt spraying method, and preferably contains ultrafine fibers such as polyester, polyamide and polyolefin.

  Patent document 10 (name of invention: Elastic Nonwoven Webs and Method of Making Same), which is assigned to BBA Nonwovens Simpsonville, is a spunbonded elastic nonwoven fabric (and a method for producing the same), The present invention relates to a nonwoven fabric containing a web of thermoplastic filaments bonded with a plastic elastomer. The spunbonding process by slot drawing provides a web having a root mean square mean recovery stretch of at least 75% with 30% stretch and one pull of the fabric.

  Patent Document 11 (Title of Invention: Elastically Stretchable Nonwoven Fabric and Fabric For Making the Same) is assigned to Unicharm Corporation, and includes filaments of thermoplastic elastomer, and the filaments are welded to each other and / or The invention relates to an elastically stretchable nonwoven fabric that is mechanically entangled and has crimped and non-crimped sites. The crimped sites are at a rate of 50 pieces / cm or more. When the crimped part is at a temperature between the melting point and room temperature by blowing hot air against the extruder and then blowing hot or cold air (at least 20 ° C. below the melting point of the filament) to the filament. Then, the warm air or cold air is blown to elongate the filament and reduce it in the radial direction, and at least partially crimp the filament surface while cooling it non-uniformly. The filaments are welded together and / or mechanically entangled to obtain a stretchable nonwoven fabric.

  Patent Document 12 (Method of Making Nonwoven Fabric Comprising Splittable Fibers) has been assigned to Polymer Group, but the fabric is at least partly further subdivided into a plurality of subcomponents by hydraulic entanglement. The present invention relates to a method of forming from splittable filaments or stable length fibers having a plurality of subcomponents to be split. A three-dimensional image transmission device having a forming surface with small holes is used to give a clear surface pattern or image to the precursor web during hydraulic entanglement. The web is preferably crushed and cross-lapped prior to imaging and patterning.

Patent Document 12 (Invention name: Stretchable Multiple Component Spunbond Web And A Process For Making), which has been assigned to DuPont, is a high-level three-dimensional system that uses stretching rolls to provide a high degree of orientation. It relates to a method for providing a spiral crimp. The filament is mechanically stretched under conditions where the polymer component remains substantially amorphous. At least a first and a second separate, arranged in an eccentric relationship in a substantially constant zone of discontinuity across the cross-section of the filament and extending substantially continuously along the length of the filament Melt-spinning a plurality of continuous filaments comprising a melt-spinnable polymer. The filament is quenched and passed over a series of rolls for annealing (from the amorphous state to the semi-crystalline), applying and releasing tension to form a helical crimp.
U.S. Pat. No. 4,426,420 US Pat. No. 4,820,572 US Pat. No. 5,151,320 US Pat. No. 5,227,224 US Pat. No. 5,540,976 US Pat. No. 5,549,964 US Pat. No. 5,534,335 US Pat. No. 5,814,390 US Pat. No. 5,910,224 US Pat. No. 5,997,989 US Pat. No. 6,689,703 US Pat. No. 6,692,541 US Patent Application Publication No. 2003/0064650

  Accordingly, there is a need to provide a nonwoven fabric that can be stretched and recovered, improves upon the prior art described above, and is easy to manufacture.

  Accordingly, it is an object of the present invention to provide a nonwoven fabric that can be manufactured from and can be stretched from a spunbonding material, for example, having an elongation value in the range of about 5% to 7%. It is said.

  In addition, the present invention provides an arbitrary hydraulically intertwined thermoplastic filamentary nonwoven fabric (spun-bonded or composite thereof) that can be stretched and manufactured to exhibit stretchability and resilience. ) Is a more specific purpose.

  The present invention further relates to a spunbonded nonwoven fabric comprising a web of filament (s), wherein the nonwoven fabric includes filament (s) that can be intertwined and / or joined together. The web is exposed and then stretched at a selected temperature in a first selected direction, the temperature providing a stretch characteristic in the second direction different from the first direction; It is a further object to provide a non-woven fabric, as has been described.

  In one embodiment, a web of fibers comprising polymer chains intertwined with one another, wherein the fibers are stretched in a first direction at a predetermined temperature and the fibers are aligned in the first direction. And refers to a nonwoven material that can extend in a selected direction such that the polymer chains within the fiber are oriented in the first direction. The fiber is then cooled to a temperature less than the temperature, and the web of fiber exhibits a property of stretching in a second direction different from the first direction, the fiber from the stretching in the second direction. Partial recovery is also possible.

  In a second alternative embodiment, reference is made to a method for providing a stretchy nonwoven material comprising the steps of forming a web of polymer filaments entangled with each other and having a predetermined Tm (melting point). is doing. In this method, the web is then stretched in a first direction at a temperature below a predetermined Tm, the fibers are aligned in the first direction, and the polymer chains in the fibers are aligned with the first direction. An orientation step is performed. In this method, the fibers can then be partially recovered from the stretching in the second direction as the nonwoven material is stretched in a second direction different from the first direction. A step of cooling to below the temperature is performed. Optionally in this method, the web can be further stretched across the width of the web, and the nonwoven material can still be stretched in a second direction across the width of the web. Further steps can be performed that can partially recover from the extension.

  The above and other objects, features and advantages of the present invention will become more apparent by considering the following description and accompanying drawings.

  In a first preferred embodiment, the present invention is directed to a nonwoven material that can stretch in a selected direction, having a web of fibers comprising polymer chains intertwined with each other. .

Preferably, the fibrous web comprises a superfine filament nonwoven fabric having a weight of 30-150 [g / m ² ] and a tear strength greater than 40 [N / 5 cm], the nonwoven fabric comprising a melt spun Made of continuous multicomponent filaments having a fineness of 1.5 to 5 dtex forming a nonwoven fabric that is stretched, directly laid down A typical multi-component filament is split to at least as much as 80% to form continuous ultrafine filaments that are joined with a fineness of 0.01 to 1.0 dtex.

  More preferably, the continuous multicomponent filament may have a continuous bicomponent filament comprising two polymers. The two polymers have a first polymer, such as a polyester polymer, and a second polymer comprising a polymer selected from the group consisting of polyamides, polyolefins, and mixtures thereof.

  In one particularly preferred embodiment, the nonwoven fabric in this application can be made from a material manufactured and sold by Freudenberg Nonwovens under the trademark Evolon, which is recognized as a textile made of ultrafine filaments. Has been. Allegedly, the material is produced in a continuous process from the granular polymer to the final textile while spinning and laying down the filaments in web form, preferably bonded together. A water jet bond is then applied to the Evolon ™ material making up the endless ultrafine filament.

  Referring now to FIG. 1, the web of fibers is fed to the opposing roller in the unwound state at the position of reference numeral 10, preheated and stretched at the positions of reference numerals 12 and 14. Thereby, it is expanded in the length direction and contracted without being restricted in the width direction. The heating is preferably performed with the web of fibers containing polymer chains having a melting point Tm, and the preheating described above is performed at a temperature below Tm, most preferably, the Tm is between 0.1 ° C and 20.0 ° C. Preheated at a lower temperature. Furthermore, the preheating temperature is set above Tg and below Tm, where Tg is the glass transition point for these polymers. As shown, the fibers are preferably aligned in the longitudinal direction and the polymer chains are also oriented in that direction.

  Further, referring now to FIG. 3, the fiber orientation (% frequency) before stretching is plotted in relation to the orientation angle, which represents the fiber orientation distribution (FOD). ing. Turning now to FIG. 4, the orientation (% frequency) of the fiber after stretching is plotted in relation to the orientation angle. Comparing FIG. 3 with FIG. 4, it is clear that the fiber orientation is shifted in the direction in which the fabric is stretched after stretching. It will be understood that the structure of the fiber before stretching is relatively isotropic and the structure of the fiber after stretching is more anisotropic.

  Next, referring again to FIG. 1, the fiber web can be arbitrarily stretched in the width direction at the position of reference numeral 16, for example, a tenter frame or the like. It turns out that it can set so that it may become a desired size by using. One skilled in the art will appreciate that the tenter frame can stretch the fabric back to its original width. In any event, the preferred procedure shown in FIG. 1 results in a web of fibers being produced when quenched and wound at the position of reference numeral 18, such web being in a first direction (longitudinal direction). ) In a second direction different from), in which case the fibers can partially recover from such elongation. It has been found that along such a line, the web can stretch to a level of about 70% in the second direction with partial recovery.

  Turning now to FIG. 2, FIG. 2 illustrates a two-step process for producing the stretchable material of the present invention. By rewinding and feeding at the reference numeral 20 and then using the rollers at the reference numerals 22 and 24, preheating and longitudinal stretching are facilitated and are described herein. So that it is heated to the desired temperature through the use of the roller. As such, the stretched fabric may be quenched and wound at the location of reference numeral 26 and used in that form. As shown, the fabric coming out at the reference numeral 26 is quenched and wound, and then optionally rewound and fed at the reference numeral 28, so that the roller When moving between them, the width direction is extended to the width selected at the position of reference numeral 30, and then rapidly cooled and wound at the position of reference numeral 32.

  In accordance with the present invention, stretchable nonwoven materials that are useful in many applications can be produced in a unique way, and the advantages of such nonwoven materials are that they provide stretchability and recoverability. Can be utilized with the ability of a non-woven fabric.

  While the invention has been described in terms of particular embodiments, it will be understood that the subject matter encompassed by the invention is not limited to those particular embodiments. Accordingly, the subject matter of the present invention is intended to cover all equivalents within the scope of the appended claims.

1 illustrates a one-step process for producing a stretchable material according to the present invention. 2 illustrates a two-step process for producing a stretchable material according to the present invention. It is a graph which shows the relationship between the fiber orientation before extending | stretching, and an orientation angle. It is a graph which shows the relationship between the fiber orientation after extending | stretching, and an orientation angle.

Explanation of symbols

10 Positions 12 and 14 supplied to opposing rollers in the rewound state 16 Preheated and extended positions 16 Positions extended in the width direction 18 Quickly cooled positions 20 Rewinded and supplied positions 22 and 24 Position 26 where the web of fibers is preheated and stretched longitudinally Position 28 where it is quenched and wound 28 Position 30 where it is rewound and fed 30 Position 32 where it is stretched in the width direction to the selected width The position to be wound with

Claims (15)

A nonwoven material that can stretch in a selected direction,
(A) a web of fibers comprising polymer chains in which the fibers are intertwined with each other,
(I) The fibers are elongated in a first direction at a predetermined temperature, the fibers are aligned in the first direction, and the polymer chains in the fibers are oriented in the first direction. ,
(Ii) the fiber is cooled to a temperature below the temperature;
With a web of fibers,
The web of fibers exhibits a property of stretching in a second direction different from the first direction, and the fibers can partially recover from the stretching in the second direction;
A non-woven material characterized by that.   The nonwoven fabric according to claim 1, wherein the polymer chain has a melting point Tm and the temperature is less than Tm.   3. The nonwoven fabric according to claim 2, wherein the temperature is less than Tm means that Tm is 0.1 ° C. to 20 ° C. lower than Tm.   The nonwoven fabric according to claim 1, wherein the polymer chain has Tg (glass transition point) and Tm, and the temperature is equal to or higher than Tg and lower than Tm.   The nonwoven fabric of claim 1, wherein the fibers elongate to about 70% in the second direction and partially recover.   The nonwoven fabric according to claim 1, wherein the second direction is substantially orthogonal to the first direction. The web of fibers contains a nonwoven fabric of ultrafine filaments having a weight of 30-150 [g / m ² ] and a tear strength greater than 40 [N / 5 cm], the nonwoven fabric being melt spun Made from continuous multicomponent filaments having a fineness of 1.5-5 dtex that are stretched and directly laid down to form a nonwoven fabric, said continuous multicomponent filaments being The non-woven fabric according to claim 1, wherein continuous non-fine filaments are formed which are divided to at least about 80% and bonded with a fineness of 0.01 to 1.0 dtex.   The nonwoven fabric of claim 7, wherein the continuous multicomponent filaments comprise continuous bicomponent filaments comprising two polymers.   9. The polymer of claim 8, wherein one of the polymers comprises a polyester polymer and the other one comprises a polymer selected from the group consisting of polyamides, polyolefins, and mixtures thereof. The nonwoven fabric described. A method for providing a nonwoven material with elasticity, comprising:
(A) forming a web of polymer filaments entangled with each other and having a predetermined Tm (melting point);
(B) The web is stretched in a first direction at a temperature below a predetermined Tm, the fibers are aligned in the first direction, and the polymer chains in the fibers are aligned in the first direction. Steps,
(C) Cooling the fibers to below the temperature at which the nonwoven material extends in a second direction different from the first direction and can partially recover from the extension in the second direction. And steps to
A method characterized by comprising:   The method according to claim 10, wherein the temperature is lower than Tm is lower than Tm by 0.1 ° C. to 20 ° C.   The method of claim 10, wherein the fiber stretches in the second direction to about 70% and partially recovers. A method for providing a nonwoven material with elasticity, comprising:
(A) forming a web of polymer filaments entangled with each other, having a predetermined Tm (melting point), and having a predetermined length and a predetermined width;
(B) elongating the web in a first direction coincident with the length direction of the web at a temperature below a predetermined Tm, aligning the fibers in the first direction, and the polymer chains in the fibers Orienting in the first direction to reduce the width of the web;
(C) cooling the fibers to below the temperature at which the nonwoven material stretches in a second direction across the width of the web and can be partially recovered from the stretch;
A method characterized by comprising:   The web can be further stretched across the width of the web so that the nonwoven material can still stretch in a second direction across the width of the web and partially recover from the stretch. 14. The method according to claim 13, comprising further steps that can be performed.   14. The method of claim 13, wherein the step of extending across the width of the web is placing the web on a tenter frame.