MXPA00002240A - Crimped multicomponent filaments and spunbond webs made therefrom - Google Patents

Abstract

Spunbond multicomponent filaments and nonwoven webs made from the filaments are disclosed. In accordance with the present invention, the multicomponent filaments contain a crimp enhancement additive. Specifically, the crimp enhancement additive is added to the polymeric component that has the slower solidification rate. The additive enhances crimp, allows for highly crimped filaments to be made at low fiber linear densities, improves the integrity of unbonded webs made from the filaments, and produces webs with improved stretch and cloth-like properties. The additive incorporated into the filaments is a random copolymer of butylene and propylene.

Description

FILAMENTS DB MULTICOMPONENTBS CURLED AND WOVEN HIDDEN AND UNITED HBCHQ8 DB THE SAME Oaapo gives the Invention The present invention is generally directed to spun and bonded multi-component filaments and n-woven fabrics made of filaments. More particularly, the present invention is directed to incorporating an additive into one of the polymers used to make multicomponent filaments. The additive improves curling, allows finer filaments, improves the integrity of the n-linked fabrics made of the filaments, improves the bonding of the filaments, and produces fabrics with improved stretch-cloth properties. The additive incorporated into the filaments is a random butylene-propylene copolymer.

Background of the Invention Non-woven fabrics are used to make a variety of products which desirably have particular levels of softness, strength, uniformity, liquid handling properties such as absorbency, and other physical properties. Such products include towels, industrial cleansers, incontinence products, filter products, infant care products, such as baby diapers, absorbent feminine care products, garments such as medical garments. These products are often made with multiple layers of non-woven fabrics to obtain the desired combination of properties. For example, disposable baby diapers made of polymeric woven fabrics may include a soft porous lining layer which is placed close to the baby's skin, a waterproof outer shell layer which is strong and soft, and a further layer of handling of inner liquids which are soft bulky and absorbent.

Non-woven fabrics such as the above are commonly made by spinning melted thermoplastic materials. Such fabrics are called spunbonded materials. Spunbonded and bonded nonwoven polymeric fabrics are typically made of thermoplastic materials by extruding the thermoplastic material through a spinning member and pulling the extruded material into filaments with a high velocity air stream to form a random fabric on the surface. a collecting surface.

The spun materials have been produced and bound with desired combinations of physical properties, especially combinations of softness, strength and absorbency, but they have found limitations. For example, for some applications, polymeric materials such as polypropylene may have a desirable level of strength eg not a desirable level of softness. On the other hand, materials such as polyethylene can, in some cases, have a desirable level of softness but not a desirable level of strength.

In an effort to produce the materials n fabrics having desirable combinations of physical properties, non-woven polymer fabrics made of multicomponent bicomponent or d filaments and fibers have been developed. The bicomponent or multicomponent polymer fibers or filaments include two or more polymeric components which remain distinct. As used herein, the filaments signify continuous threads of matter and the fibers mean discontinuous or cut threads having a defined length. The first and subsequent components of multicomponent filaments are arranged in essentially different zones across the cross section of the filaments and extend continuously along the length of the filaments. Typically, one component exhibits different properties to those of another so that the filaments exhibit properties of the two components. For example, one component may be polypropylene which is relatively strong and the other component may be polyethylene which is relatively soft. The final result is a strong but soft nonwoven fabric.

To increase the volume and filling of two-component non-woven fabrics to improve fluid handling performance or to improve the feeling of "fabric type" fabrics, the bicomponent filaments or fibers are frequently curled. The bisomponent filaments may be and be mechanically crimped or, if the appropriate polymers are used, curl naturally. As used herein, a naturally curled filament is a filament that is crimped by activating a latent ripple contained in the filaments. For example, in one embodiment, the filaments can be naturally curled by subjecting the filaments to a gas, such as a heated gas, after being pulled.

In general, it is more preferable to build filaments that can be naturally curled as opposed to having to curl the filaments in a separate mechanical process Difficulties have been experienced in the past, however, to produce filaments that naturally curl in the extent required for the particular application. Also, it has been found that it is very difficult to produce naturally curly fine filaments, such as filaments having a linear density of less than 2 deniers. Specifically, the pulling force used to produce the fine filaments usually avoids or removes any significant latent curl that could be contained in the filaments. As such, there is a current need for a method for producing multicomponent filaments with improved ripple properties. There is also a need for non-woven fabrics made of such filaments.

Synthesis of the invention The present invention recognizes and refers to the above disadvantages, and to other constructions and prior art method.

Therefore, an object of the present invention is to provide improved nonwoven fabrics and methods for making same.

Another object of the present invention is to provide non-woven polymeric fabrics including highly crimped filament and methods for economically manufacturing same.

A further object of the present invention is to provide a method for controlling the properties of a non-woven polymeric fabric by varying the degree of curling of the filaments and fibers used to make the fabric.

Another object of the present invention is to provide an improved process for naturally curling multi-component filaments.

It is another object of the present invention to provide a method for naturally curling multi-component filaments by adding a butylene-propylene copolymer to one of the components of the filaments.

Yet another object of the present invention is to provide a naturally curled filament having a linear density of less than 2 deniers.

Another object of the present invention is to provide a bicomponent filament made of polypropylene and polyethylene, wherein a rizad enhancement additive has been added to the polyethylene.

It is still another object of the present invention to provide a process for naturally curling multicomponent filaments containing polypropylene and polyethylene in which the curing enhancement additive and the claimed polymer have been added to the polyethylene.

Another object of the present invention is to provide a curling improvement additive which also improves the strength of spunbonded fabrics made of filaments containing the additive.

These and other objects of the present invention are achieved by providing a process for forming a non-woven tel. The process includes the steps of spinning with melting the filaments of ultisomponents. Multicomponent filaments d include a first polymer component and a second polymer component. The first polymeric component has a faster solidification rate than that of the second polymer component to provide the filaments with latent curing. The second polymer component contains a curing enhancement additive which is a d-butylene-propylene copolymer.

Once melted and spun, the multicomponent filaments are pulled and curled naturally. Next, the multicomponent crimped filaments are formed into a non-woven fabric for use in various applications.

In one embodiment, the second polymer component may include polyethylene. The butylene-propylene copolymer may be added to the second polymer component in an amount of less than about 10% by weight, and particularly from about 0.5% to about 5 by weight. Preferably, the butylene-propylene copolymer is a random copolymer containing less than about 20 by weight of butylene, and particularly about 14% by weight of butylene.

The first polymer component, on the other hand, is a polypropylene. Other polymer that may be used include nylon, polyester and polypropylene copolymer such as a propylene-ethylene copolymer.

In accordance with the present invention, it has been discovered that the butylene-propylene copolymer also functions as a polymer compatibilizer. In particular, it has been found that the sopolymer allows a better homogeneous mixture between the different polymers. In this aspect, the first polymer component, according to the present invention, may also contain a reclaim polymer. E claim polymer, as used herein, are the polymer fragments that are recycled and added to the filaments. For example, the reclaimed polymer may comprise a mixture of polyethylene, polypropylene and copolymers of propylene and ethylene, and may be obtained from trimmed edges of previously formed non-woven fabrics. In the past, difficulties have been experienced in recycling the reclaimed polymer, especially the bicomponent reclaim polymer, and incorporating them within the filaments without adversely affecting the physical properties of the filaments.

These and other objects of the invention are also achieved by providing a non-woven fabric made of crimped, multi-component yarns spun and bonded. The multicomponent crimped filaments are made of at least one first polymer component and one second polymer component. In particular, the polymer components are selected so that the first polymer component has a faster solidification rate than the second polymer component. According to the present invention, the second polymer component contains an improved curling additive. Specifically, the curling enhancement additive is a random butylene propylene copolymer.

For example, in one embodiment, the crimped filaments may be bicomponent filaments which include a polypropylene component and a polyethylene component. The random copolymer of butylene-propylene may be added to the polyethylene component in a sanity up to about 5% by weight. Preferably, the random butylene-propylene sopolymer is about 14% per weight of butylene.

Due to the addition of the curly enhancement additive, multicomponent filaments can have a very low deni and still be naturally crimped. For example, the deni of the filaments may be less than two and particularly less than about 1.2.

In this regard, the present invention is also directed to a multicomponent naturally occurring filament filament that includes at least a first polymer sulphate and a second polymer hydrometer. The first polymer component may be, for example, polypropylene. The second polymeric component, on the other hand, can be, for example, polyethylene and can contain a curling enhancement additive in a sanity sufisient to allow the filaments to be naturally curled to a denier of less than about d 2 and particularly of less of about 1.2.

Other objects, features and appearances of the present invention are discussed in more detail below.

Brief Description of the Drawings A complete and enabling description of the present invention, including the best mode for performing it, for one with ordinary skill in the art, is more particularly set forth in the remainder of the description including reference to the accompanying figures in the which: Figure 1 is a schematic drawing of a line of prose to have a preferred embodiment of the present invention; Figure 2A is a schematic drawing illustrating the cross section of a hesho filament according to an embodiment of the present invention with polymer components A and B in a side-by-side arrangement; Y Figure 2B is a schematic drawing illustrating the cross section of a filament made according to an incorporation of the present invention with polymer components A and B in an eccentric sheath / core arrangement.

The repeated use of reference characters in the present description and in the drawings is intended to represent the sarasteristises are equal or analogous elements of the invention.

Detailed Description of the Preferred Incorporations It is understood by one with ordinary skill and art that the present description is a breakdown of the exemplary insorporations only, and that no attempt is made to limit the broader aspects of the present invention, its aspersons broader are insorporated in the sonstrussión d example.

The present invention is generally directed to the multi-component filaments and the spun and bound fabrics produced from the filaments. In particular, the filaments are naturally curdled in, for example, a helisoidal arrangement. The curling of the filaments increases the volume, the softness and the fall. Non-woven fabrics also have improved fluid handling properties and have an improved cloth tip look and feel.

The multi-component filaments for use in the present invention contain at least two polymer component. The polymeric solvents may be, for example, in a side-by-side configuration or in an eccentric sheath-core configuration. The polymer components are selessionados of semicrystalline and semicrystalline thermoplastic polymers the suals have different rates of solidifisasión are resposto each other in order that the filaments suffer the natural ripple. More particularly, one of the polymer components has a fast solidifisation rate m than that of the other polymer components.

As used herein, the polymer solidification rate refers to the rate at which a melted softened polymer hardens and forms a fixed structure. It is believed that the solidification rate of a polymer is influenced by different parameters including the melting temperature and the crystallization rate of the polymer. For example, a fast solidification polymer typically has a melting point of about 10 ° C or higher, more desirably around 20 ° C or more, and more desirably about 30 ° C or more than that of a polymer that It has to be understood, however, that both polymeric components can have similar melting points if their crystallization rates are edibly different.

Even when it is disconcerted, it is believed that the latent rizad of the multisomponent filaments is sreacted in the filaments due to the differences in the properties of dyeing between the polymeric somponents. In addition it is said that the main cause of the shrinking difference between the polymer components is the incomplete crystallization of the slower solidifisation polymer during the processing of the fiber. For example, during the formation of the filaments, when the solidification polymer is solidified, the slow solidification polymer is partially solidified and does not pull anymore and therefore does not further experience a signifying force of orientation. In the absence of a guiding force, the slow-forming solidified polymer does not crystallize adisionally in signifisan form while cooling and solidifying. Therefore, the resulting filaments possess a latent ripple, and such a latent rizad can be activated by subjecting the filaments to a process that allows sufficient molecular motion of the slow-curing polymer polymer molecules to facilitate additional shrinkage and crystallization.

The present invention is directed to adding a curing enhancement additive to the polymeric component which has the slowest solidification rate in order to further decelerate the solidification rate of the polymer. In this way, the differences between the solidification rates of both polymeric components becomes even greater when creating multi-component filaments that have an improved latent ripple. In particular, the curly improvement additive of the present invention is a random butylene-propylene sopolymer.

In addition to creating multicomponent filaments having a greater natural curl, it has also been found that the curl enhancement additive of the present invention provides many other benefits and advantages. For example, because the filaments of the present invention have a higher degree of curling, the fabrics and fabrics made of the filaments have a higher volume and a lower density. By being layers of lower density fabrics less material is required to haser fabrics of a specified thickness and fabrics are therefore less expensive to produce. In addition to having lower densities, the telos have also been found to be more of a cloth type, to have a softer feel, to have more stretch, to have a better recovery and to have a better abrasion resistance.

As a particular advantage, it has also been unexpectedly discovered that the curling additive of the present invention further improves the strength and integrity of the unbound fabrics made of the filaments. For example, it has been found that adding only 1% by weight of the additive can more than double the unbonded strength of the fabric. By having a greater integrity of the unbound fabric, the fabrics of the present invention can be processed at faster speeds. In the past, in order to run at higher speeds spun and bound unbound fabrics had to pretend to be together. Such steps are not necessary, since fabrics made according to the present invention are processed.

In addition to having an increased strength, the spun and bonded fabrics made according to the present invention also have dramatically reduced fabric handling problems when processed at higher speeds. For example, the occurrence of eyebrows, flip-flops and stretch marks are significantly reduced when the curling enhancement additive within the filaments is present. More particularly, the fabrics incorporating the filaments made according to the present invention have a smaller mush tendency to protrude from the fabric, but instead have a greater tendency to wear over the surface of the fabric. As such, the filaments are less easy to penetrate in the foraminous superfisie on which the fabric is formed, making the reworking of the fabric of the superfisie so much easier.

Another unexpected benefit from the use of the curling enhancement additive of the present invention is that the additive also functions as a polymer compatibilizer. In other words, the additive facilitates the homogeneous mixing of different polymers. Therefore, the polymer component containing the additive may contain a mixture of polymers if desired. For example, in an insorporation of the present invention, the polymeric substance which is the additive of the present invention can also contain a resin polymer such as the resorbed polymer residues of the pre-formed and spun-bonded fabric springs and of two-component fabrics. particularly.

An additional advantage for the curl enhancement additive of the present invention is that the additive allows the formation of very fine multicomponent filaments having a relatively high natural curl. In the past, it was very difficult to create fine filaments, such as d less than 2 deniers, that had a relatively high natural ripple. In the past, the pulling force used to produce the fine fibers usually avoided or removed any significant latent rind that was present within the filaments. The filaments made according to the present invention, on the other hand, can have more than 10 crimps per inch to less than 2 denier, and even less than 1.2 denier.

In addition to the advantages listed above, it has also been discovered that the curl enhancement additive of the present invention improves the thermal bond between the filaments. In particular, the rizad enhancement additive has a wide melting point range and has a relatively low melting temperature, the fasilite sual l junction.

The fabrics and fabrics of the present invention are particularly useful for making various products including gas and liquid filters, articles for the personal sweating of garment materials. Personnel care items include infant care products such as disposable baby diapers, child care products, such as learning salts, and produst for adult care such as incontinence products. and the produtos for the woman's sweating. Tale garments add insidious costumes, work clothes and the like.

As distilled above, the present invention fabric includes multi-component multicomponent filaments that comprise at least one first and one second polymer component. A preferred insorporation of the present invention is a polymeric fabric comprising synthetic bent component filaments comprising a first polymer semidarm A and a second bicomponent bicomponent. The bicomponent filaments have a transverse sesssion, a length and a peripheral surface. The first second components A and B are arranged in essentially different areas through the cross section of the d-component filaments and extend continuously along the length of the bicomponent filaments. The second somponent B at least part of the peripheral surface of the bicomponent filaments continuously along the length of the bicomponent filaments.

The first and second components A and B are arranged in either a side-by-side array as shown in Fig. 2A or as an exsensed sheath / core arrangement som is shown in Fig. 2B so that the resulting filaments They exhibit a natural helisoidal ripple. The polymer somponent A is the nullification of the filament and the somponent of polymer B is the sheath in the sheath / nuscle arrangement. The methods for extruding the multiple polymeric filament filaments within such arrangements are well known to those of ordinary skill in the art.

A wide variety of polymers are suitable for practicing the present invention including polyolefins (such as polyethylene and polypropylene), polyesters, polyamides, and the like. The polymer component A and the polymer component B should be selected so that the resulting bicomponent filament is capable of developing a natural helisoidal ripple. Preferably, the polymer component A has a faster solidification rate than that of the polymer component B. For example, in an incorporation, the polymer component A can have a melting temperature higher than that of the polymer component B. Preferably , the polymer component A suffers polypropylene or a random polypropylene and ethylene sopolymer. In addition to containing polypropylene, the polymer component A can also be nylon or a polyester.

The polymer component B, on the other hand preferably comprises polyethylene or a random copolymer of propylene and ethylene. Preferred polyethylenes include linear low density polyethylene and high density polyethylene.

The adesuitable materials for preparing the multi-component filaments of the present invention include the PD-3445 polypropylene available from Exxon of Houston, Texas, the random polypropylene and ethylene solvent available from Exxon, the linear low density polyethylene ASPUN 6811A and 255 available from Dow. Chemisal Company, Midland, Mishigan, and high density polyethylene 25355 and 12350 available from Do Chemisal Company.

When the polypropylene is the somponent A and the polyethylene is the somponent B, the bisomponent filaments can range from about 20 to about 80% by weight of polypropylene and from about 20 to about 80 by the polyethylene feel. More preferably, the filaments range from about 40 to about 60 by weight of polypropylene and from about 40 to about 60% by weight of polyethylene.

As described above, the curling enhancement additive of the present invention is a random butylene and propylene sopolyme and the sual is preferably polyethylene added to the polymeric component B. The random butylene-propylene copolymer is preferably from about 5% to about 20% by weight butylene. For example, a somatically available produst that can be used as the curly improvement additive is produs No. DS4D05 marketed by Union Carbide Corporation Danbury, Connectisut. The produsto No DS4D05 is a random butylene-propylene sopolymer which is 14% by weight of butylene and 86% by weight of propylene. Preferably, the butylene-propylene copolymer is a film-class polymer having an MFR (melt flow rate) of from about 3.0 about 15.0, and particularly having a melt flow rate of from about 5 to about 6.5 In order to combine the curing enhancement additive with a polymer component B, in one embodiment, the polymers can be mixed together and extruded together during the formation of the multi-component filaments. In an alternate insorporation, the curing enhancement additive and polymer component B may be, for example polyethylene, mixed with melt before they are formed in the filaments of the present invention.

In general, the rizad enhancement additive can be added to the polymer component B in an amount of less than 10% by weight. When the polymeric somponent contains polyethylene, preferably the crimping enhancement additive is added in an amount of from about 0. to about 5% by weight based on the total weight of polymer component B. In the event that too much is added. From the random copolymer of butylene-propylene to the polymer component, the resulting filaments can become very curly and interfere adversely with the formation of a non-woven fabric.

It is believed that the random copolymer of butylene-propylene, when added to a polymer such as polyethylene, will destabilize the solidification rate and the crystallization rate of the polymer. In this way, a greater difference is created in the solidification rates between the polymer components used to make the filaments, thereby increasing the latent curling of the filaments.

In an alternate incorporation of the present invention, in addition to adding the curd enhancing additive to the polymer component B, the reclaimed and recirculated polymers are also added to the polymer somponent. As described above, it has been found that the curl enhancement additive of the present invention also facilitated homogeneous mixing between the polymers. Specifically, the random butylene-propylene sopolymer has been shown to be a mixture between the polyethylene and a reclaimed or used polymer containing a polypropylene polypropylene mixture. In this embodiment, the reclaimed polymer used can be added to the polymeric somponent in a sanitide of up to about 20% by weight. Preferably, the resin polymer used is resoled from springs and fragments of previously formed non-woven fabrics. The fact that such polymers are not only decreases the sanctity of matter necessary to make the non-woven fabrics of the present invention, but also limits the amount of waste that is produced.

A process for producing multi-component filaments and non-woven fabrics according to the present invention will now be explained in detail by referring to Figure 1. The following process is similar to the current description of the United States Patent No. 5,382.40. granted to Pi e and others, the sual is insorporated here by reference in its entirety.

Returning to Figure 1, a process line 10 is dessribe to prepare a preferred embodiment of the present invention. The process line is arranged to produce continuous bicomponent filaments, but it should be understood that the present invention comprises woven fabrics made of multi-component filaments having more two somponents. For example, the fabric of the present invention may be filaments having three or four somatums.

The printing line 10 includes a pair of extruders 12A and 12B for separately extruding a polymeric component A and a polymeric component B. The polymeric component A is fed into the respective extruder 12 from a first container 14a and a polymer component B fed in. of the respective extruder 12b from a second hopper 14b. The polymer components A and B are fed from the extruders 12a and 12b through the resilient polymer conduits 16a and 16b to a spinner member 18.

The spinning organs for extruding domponent filaments are well known to those of ordinary skill in the art and therefore are not described here in detail. Generally described, the spinner member 18 includes a box containing a spin pack which insulates a plurality of plasmas stacked one on the other are a pattern or pattern of openings arranged to create flow paths for directing the polymer components A and B separately through the spinning member. The spinner organ 18 has the openings arranged in one or more rows. The openings of the spinner organ form a sorting that extends down to the filaments when the polymers are extruded through the spinning organ. For the purposes of the present invention, spinner organ 18 can be arranged to form eccentric or side-by-side bicomponent core / sheath filaments illustrated in Figures 2A and 2B.

The line 10 also includes a cooling blow 20 collided on one side of the filament sortin extending from the spinner member 18. The air from the cooling air blower 20 cools the filaments that extend from the spinner member. 18. The cooling air can be directed from one side of the filament sortina som is shown in figure 1 or from both sides of the filament d sortina.

A vacuum cleaner or a fiber pulling unit 2 is soldered downstream of the spinner member 18 and resides the cooled filaments. The suction fiber pulling units for use in the melt spinning polymers are very sound as they are dissipated above. The fiber jade units for use in the process of the present invention include a linear fiber vacuum cleaner of the type shown in U.S. Patent No. 3,802.81 and the eductive guns of the type shown in U.S. Pat. the United States of North America Nos. 3,692,618 and 3,423,266, the descriptions of which are incorporated herein by reference.

Generally described, the fiber pull unit 22 includes an elongated vertical probe through which the filaments are pulled by sucking the air that enters from the sides of the condenser and flows down through the sondatum. A vent or blower 24 supplies the suction air to the fiber pulling unit 22. The suction air pulls the filaments and ambient air through the fiber pull unit.

An endless foraminous forming surface 26 is welded down from the fiber pull unit 22 and receives the sonorous filaments from the outlet opening of the fiber pull unit. The forming surface 26 is displaced around the guide rollers 28. A vessel 30 loosely attached to the forming surface 26 where the filaments are deposited pulls the filaments on the surface of the forming surface.

The process line 10 further includes a joining apparatus such as the thermal point bonding rolls 3 (shown in phantom) or an air through bonding device 36. The fittings through thermal point and the fittings through air d are Very well known by those experts in the art and not dissuten here in detail. Generally, the air through link 36 includes a perforated roller 38 which receives the fabric and a cover 40 surrounding the perforated roller. Finally, the line 10 includes a roller 4 for taking the finished fabric.

To operate the prosecution line 10, the hoppers 14 and 14b are filled with the respective polymer components and B. The polymer components A and B are melted extruded by the respective extruders 12a and 12b through the polymer condustos 16a and 16b and the spinner 18. Even if the temperatures of the melted polymers vary depending on the polymers used, suar is used in polypropylene and polyethylene, the aromatics A and respec- tively, the preferred temperatures of the sweat polymer are extruded ranging from about 370 to about 530 °. F and preferably vary from 400 ° to about 450 ° F.

As the extruded filaments extend below spinning organ 18, a stream of air from the cooling blower 20 at least partially cools the filaments to develop a latent helical ripple in the filaments. The cooling air preferably flows in a direction essentially perpendicular to the filament. the length of the filaments at a temperature of about 45 ° to about 90 ° F and at a rate of from about 100 to about 400 feet per minute.

After cooling, the filaments are drawn into the vertical groove of the fiber pull unit 22 by means of the flow of a gas, such as the air from the heater or from the blower 24 through the fiber jaw unit. . The fiber pulling unit is preferably only 30 to 60 inches below the bottom of the spinning organ 18. The temperature of the air supplied from the heater to the blower 24 is sufficient to activate the latent ripple. The temperature required to stimulate the latent curling of the filaments varies from about 60 ° F to a maximum temperature of the melting point of the lower melted somponent d which is the second component B.

The actual temperature of the air that is provided for the sink or blower 24 will generally depend on the linear density of the filaments being produced. For example, it has been found that at plus 2 denier, no heat is required in the fiber pulling unit in order to naturally curl the filaments, which is a further advantage of the present invention. In the past, air that was being supplied to the pulled fiber unit 22 typically had to be blown out. The finer filaments of about 2 denier heshos according to the present invention, however, will generally require putting on sontaste with the heated air in order to induce the natural rizad.

The temperature of the air from the heater 2 can be varied to achieve different levels of curling. Generally, a higher air temperature produces a higher number of crimps. The ability to control the curled degree of the filaments is particularly advantageous because it allows one to change the resulting density, the pore size distribution and the fabric drop mediant by simply adjusting the air temperature in the d unit pulled from the fiber.

The crimped filaments are deposited through the outlet opening of the fiber pulling unit 22 to the movable forming surface 26. The vacuum 20 pulls the filament against the forming surface 26 to form an unbonded non-woven fabric. filaments sontinuous. In the past, the tel was then typically compressed lightly by compression roller and then thermally bonded by the rollers 34 or joined through air in the air-through linker 36. As described above, however, It has been found out that non-woven fabrics made according to the present invention have an increased integrity and strength when they contain the curl enhancement additive. Since very little pre-pressing by the pressure roller or any other type of pre-assembly station is necessary in the process line 10 before the supply of the fabrics to the joining station. In addition, due to the insisted resistances of the non-woven fabrics according to the present invention, the line speeds can be increased. For example, l line speeds may vary from about 150 pi per minute to about 500 feet per minute.

In the air-binding unit 36 as shown in FIG. 1, the air having a temperature above the melting temperature of the component B and below the melting temperature of the component A is directed from the cover 40, through of the fabric, and is inside the perforated rod 38. The hot air melts the lowest melted polymer component B and therefore forms bonds between the filaments of the component component to integrate the fabric. When polypropylene and polyethylene are used as the polymer domains A and B respec- tively, the air flowing through the junction through air preferably has a temperature which varies from about 230 ° to about 280 ° F and a velocity of from about 100 to about 500 feet per minute. The time of permeability of the tissue in the linker through air is preferably less than about a few seconds. It should be understood, however, that the parameters of the binding agent through air depend on factors such as the type of polymers used and the thickness of the fabric.

Finally, the finished fabric is wound on the winder roller 42 and is ready for an additional treatment or use. When used to make liquid absorbent articles, the fabric of the present invention can be treated with conventional surface treatments or contain conventional polymer additives to improve the fabric stability. For example, the fabric of the present invention can be treated are modified silanes and siloxanes are polyalkylene oxide such somo polydimethyl siloxane modified with polyalkylene oxide is dessribe in the patent of the United States of North America No. 5,057,361. Such treatment d superfisie improves the wetting of the fabric.

When united through air, the fabric of the invention presented sarasteristically has a relatively high elevation. The helisoidal curling of the filaments is an open fabric estrustura are wet parts sustansiale between the filaments and the filaments are united in sontasto points. The fabric bonded through air of the present invention typically has a density of from about 0.015 g / ss to about 0.040 g / ss and a basis weight of about 0.25 to about 5 ounces per sudarrada yard and preferably from around 1.0 to about 3. ounces per suadrada yard.

Linear filament density generally ranged from less than 1.0 to about 8 denier. As it was dissolved above, the curling improvement additive of the present invention allows the production of highly dense fine filaments. In the past, naturally curly fine filaments were difficult if not impossible to produce. According to the present invention, filaments having a natural curl of at least about 10 crimps per inch can be produced at linear densities of less than 2 denier, particularly less than about 1.2 denier. For most non-woven fabrics, it is preferable for filaments to have from about 10 crimps per inch to about 25 crimps per inch. From a partiscular advantage, the filaments having a natural ripple in the above-mentioned range can be produced according to the present invention at a lower linear density than what had been possible in the past.

The thermal point junction can be brought to the attention of the United States Patent No. 3,855,046, its name being insorporated here by referensi. When it is attached to a thermal point, the fabric of the present invention exhibits an appearance more than type of cloth and, for example, it is useful as an external sub-piece for articles for personal sweating or for a garment material.

Although the joining methods shown in FIG. 1 are thermal bonding and air binding, it should be understood that the fabric of the present invention can be joined by other means such as the furnace joint, the ultrasonic joint, the hydroentanglement or combinations of the same. Such binding techniques are very popular because they are an ordinary skill in art and do not dissolve here in detail.

Even though the preferred method for carrying out the present invention is to put the multi-constituent filament in the sontasto, it is the suction air, the present invention includes other methods to astivate the latent helisoidal curling of the sonorous filaments before the filaments are formed. in a cloth. For example, multi-component filaments d can be put in sontasto are the air before cooling but up the aspirator. In addition, multi-component filaments can be put into sontaste or air between the aspirator and the telforming surface. In addition, the filaments can also be exposed to electromagnetic energy such as microwaves or infrared radiation.

Once produced, the non-woven fabrics of the present invention can be used in many different and varied aplissations. For example, fabrics can be used in filter products, in liquid absorbent products, personal care articles, in garments, and in various other products.

The present invention may be better understood, they are reference to the following examples.

Example No. 1 The following example was carried out in order to distinguish the differences between the filaments and the woven fabrics heshas are the curling improvement additive of the present invention and the filaments and non-woven fabrics constructed in the curling enhancement additive.

Two spun and bonded fabrics of bisomponent which were generally produced in agreement are the process described in US Pat. No. 5,382,400 (d Pike et al.). In both fabrics, the filaments were rounded and the transverse sessión are the two somponents arranged in a sonfigurasidn from side to side. One side of the filaments was made primarily of polypropylene (Exxon 34455), while the other side was made primarily of polyethylene (Dow 61800). In both fabrics, the polypropylene (PP) side had a sanitation of 2% by weight. additive of 50% d polypropylene and 50% Ti02.

In the first fabric (Fabric A), according to the present invention, the polyethylene (PE) side contained in a holiness of 2% a random sopolymer of 14% butylene and 86% propylene (Union Carbide DSD05). The polyethylene side of the other fabric (Fabric B), on the other hand, was 100% polyethylene.

Both fabrics were produced at a total polymer yield of 0.35 ghm of polymer per orifisium at an orifisium density of 48 orifisiums per inch of ansho were bound through air at a temperature of 265 ° F. L Fabric A occurred at a line velocity of 44 feet per minute while Fabric B occurred at 37 feet per minute. The line speed was used to control the base weight, all the other conesions of the process continued. Both fabrics had a weight of 2.6 ounces per suadrada yard (osy).

The fabrics were tested respecting the peak voltage, the peak voltage and the peak energy (3 inch strip) in both the machine direction and the cross machine direction (CD) according to the norm. ASTM D-5035-90 and for a salibre under a twill of 0.05 pound per superada inch are a Starrett-type salmore tester. The density of cloth is salsuld of the base weight and of the salibre. The curling cloth was salified on a shelf of 1 to 5 subjectiv are the number 1 = without curled and the number 5 = curled very high. L linear fiber density was salculated from the diameter of the filaments (measured by the misrossop) and the polymer density. The resistensia of the unbonded fabric was determined by resolestar a length of fabric that had not yet entered the jointer and placing it gently on the floor. The cloth was then slowly and gently lifted from one extremity until the voltage failure was felt. The length of the tel that was lifted to the point of the voltage failure was recorded as the breaking length of the unbonded web.

The test results are shown in the following table.

Fabric Properties A S B Fabric A Fabric B Filament Linear Density (denier) 1.3 1.3 Filament Curl Index 4.0 1.0 Fabric Base Weight (osy) 2.6 2.6 Fabric Caliber (inch) 0.135 0.090 Fabric Density (g / cc) 0.026 0.038 Unbound Fabric Tension Length Break (inch) 66 18 Joint Fabric Tension Properties: Peak MD Load (pound) 6.5 10.9 Stress MD Floor (%) 46 20 Energy Floor MD (inch-pound) 4.7 4.4 Load Floor CD (pound) 10.6 22.3 Tension Floor CD (%) 138 66 Energy Floor CD (inch-pound) 24 32 The results show that the Tela A in relasió to the Tela B is entangled of filaments having greater curl it has a superior salibre (and therefore a lower density). Fabric A also had a greater unbound fabric resistensia. Even if the tension floor twigs of Tela B are about twice as large as those of Fabric A, the tensile values of Fabric A are greater than those of the Fabric around the same torso. The fabric floor energies, particularly in the direction of the machine, are similar.

From a partisan meaning, it is noted that the linear densities of both sets of filaments were low m, around 1.3 denier. As shown, the filaments made containing the curl enhancement additive of the present invention had a high natural curl while the filaments that did not contain the additive did not experience significant crimping. As described above, in the past, it has been very difficult to create a naturally curled filament with low linear densities.

Example No. 2 The following example was carried out in order to demonstrate the ability of the additive of the present invention to facilitate mixing between the different polymer materials.

The polyethylene / polypropylene bisomponent filaments were produced and formed in a spunbond non-woven fabric and generally agreed upon are the proses dessrito in Example 1 and disclosed in U.S. Patent No. 5,382,400 issued to Pike and others. The polyethylene side of the bisomponent filaments was charged with 20 by weight of the flame-retardant polymer. Specifically, the resourced polymer was an ezsla of polypropylene and polyethylene that had been collected from the cuttings of a previously formed non-woven fabric.

In accordance with the present invention, the polyethylene component also contained 5% by weight of random butylene / propylene copolymer identified in Example 1.

It was observed that by adding the copolymer of butylene / propylene of the present invention, the polymer d claim was mixed easily, the polyethylene component produced a polymeric material that could be spun in filaments, the suals, in turn could be curled naturally . In addition, it was discovered that the filaments are very low linear densities can be prodused. For example, at a polymer product of 0.4 ghm and at a fiber pull pressure of 7.4 psi, the filaments were produced having a linear density of 1.18 denier.

In the past, attempts have been made to produce bicomponent filaments by blowing resin polymer. In the absence of the additive additive of the present invention, however, it was not possible to spin the polymer mixture into filaments.

These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit of the present invention, which is more particularly established in the appended claims. In addition, it should be understood that the aspestos of the various modalities can be exchanged both in whole or in part. In addition, those with ordinary skill in the art will appreciate that the foregoing description is by way of example only, and that no attempt is made to limit the interest so far in dessrita in such annexed claims.

Claims (29)

R E I V I N D I C A C I O N S

1. A process for forming a non-woven fabric that involves the steps of: melt and spin the multisomponent filaments, the filaments have a polymer component and a second polymer component, the first polymer component has a faster solidification rate than the second polymeric component, said polymer component contains a butylene propylene copolymer; pulling said multicomponent filaments; curl naturally dots filaments multisomponente; Y then form multi-component d-filament fabrics in a non-woven fabric.

2. Such a process is claimed in Clause 1, which is sarasterized because the second polymeric somponent comprises polyethylene.

3. A process as claimed in Clause 1, characterized in that the butylene propylene dienepolymer comprises a random copolymer containing up to about 20% by weight of butylene.

4. A process as claimed in Clause 1, characterized in that the butylene propylene copolymer is added to the second polymer powder and has a sanity of up to about 10% by weight.

5. A process such as this is claimed in Clause 1, which is sarasterized because the butylene propylene copolymer is added to the second polymer powder and has a sanity of up to about 0.5% to about 5% by weight.

6. Such a process is claimed in clause 2, which is sarasterized because the first polymeric substance is polypropylene.

7. Such a process is claimed in clause 2, characterized in that said first polymeric somponent comprises a selected material which is comprised of nylon, polyester and propylene-ethylene copolymers.

8. Such a process is claimed in Clause 1, which is sarasterized because the second polymeric somponent furthermore offers flame retarded polymers, flame retardant polymers, polypropylene, polyethylene, propylene and ethylene polymers.

9. A process as claimed in clause 1, sarasterized because multicomponent filament d has a linear density of less than about 2 denier.

10. A process for forming a non-woven fabric comprising the steps of: melting and spinning bicomponent filaments, said bicomponent filaments comprise a first polymeric component and a second polymer component, said first polymer component comprises polypropylene, said second polymeric component comprising a polyethylene batch and a butylene-propylene sopolymer; pull off the filaments of bisomponent; curling dishos filaments of bisomponent; Y i. then forming said bicomponent filaments into a non-woven fabric.

11. A process as claimed in clause 10, sarasterized in that the dish-shaped filaments are crimped by subjecting said filaments to a flow of a gas.

12. A process as claimed in clause 10, sarasterized in that said butylene propylene copolymer is present in the second polymer powder and has a sanity of from about 0.5% to about 5% by weight.

13. Such a process is claimed in Clause 12, which is sarasterized in that said butylene propylene copolymer comprises a random polystyrene which is about 14% by weight butylene.

14. Such a process is claimed in Clause 10, which is sarasterized in that the second polymeric somponent also contains flame-retarded polymers, flame-retardant polymers, polypropylene, polyethylene, propylene and ethylene polymers.

15. Such a process is claimed in clause 14, characterized in that said reclaimed polymers are present in said second polymeric component in a sanity of up to about 20% by weight.

16. Such a process is claimed in Clause 10, which is sarasterized because the d-component filaments have a linear density of less than about d 2 deniers. '

17. Such a process is claimed in Clause 10, characterized in that said curled bicomponent filaments are at least 10 crimps per inch.

18. A non-woven fabric which comprises crimped filaments of multi-component spun yarns and joined, multi-component curled filament cloths has at least one prime polymeric substance of a second polymeric somaponder, said first polyester polymer has a faster solidification rate than that of aluminum. second polimériso somponente, dish second polimériso somponente sontiene a random butpolímero d butileno-propileno.

19. Such a non-woven fabric is claimed in clause 18, characterized in that said second polymeric package comprises polyethylene.

20. Such a non-woven fabric is claimed in Clause 19, which is sarasterized because the random butylene-propylene divalent polymer is present within the dispersion according to a polymeric solids content of up to about 5 by weight.

21. Such a nonwoven fabric is claimed in clause 20, sarasterized because the first polymeric somponent comprises polypropylene.

22. A non-woven fabric as claimed in clause 21, characterized in that said random butylene-propylene copolymer contains up to about 20% by weight d-butylene.

23. A non-woven fabric as claimed in Clause 22, sarasterized in that said multi-component crimped filaments have a linear density of less than about 2 deniers.

24. A naturally bicomponent bicomponent filament comprising at least a first polymer component and a second polymer component, the first polymeric somponent has a faster solidification rate than the said second polymer component, said filament being a curling enhancement additive, Additive of curly improvement additive is added in a sanctity sufisient so that dish filament has at least 10 curled per inch, dish multisomponent filament has a linear density of less than about 2 deniers.

25. A multi-component filament naturally ripple as claimed in clause 24 facesterized because the filament has a linear density d less than about 1.2 denier.

26. A multisomponent filament naturally rized as claimed in clause 24 facesterized because said second polymer component comprises polyethylene and wherein a dimerized improvement additive contains a random butylene-propylene sopolymer is contained within the second polymer solder.

27. A filament of multisomponent naturally rized as claimed in clause 26, characterized in that said first polymer component comprises polypropylene.

28. A process for improving the joined strength of a spun and bonded nonwoven fabric, said process comprises the steps of: incorporating in a first polymeric component butylene-propylene sopolymer; melting and spinning the multi-component filaments of disho first polimériso somponente and at least of a second polymer component; pulling said multi-component filaments; Y then forming said multisomponent filaments d in a non-woven fabric wherein the butylene-propylene disulfide polymer is present in a fabric in sufficient strength to increase the strength of said fabric before it is thermally bonded.

29. A process as claimed in clause 28, characterized in that the butylene propylene solpolymer is added to the first polymer solder in a sanity of from about 0.5% to about 5% by weight R E S U M E N The threads of multi-component filaments and bonded and the non-woven fabrics heshas of disho filaments are dessritos. According to the present invention, the multi-component filaments are an improvement additive. Specifically, the curing improvement additive is added to the polymeric somaponite which has the slowest solidifisation rate. The additive improves curling, allows highly curled filaments to be made at low fiber linear density, improves the integrity of n-linked fabrics made of the filaments, and produces fabrics with improved stretch and wipe-type properties. The additive incorporated within the filaments is a random butpolymer d butylene and propylene.