MXPA00003051A - Crimp enhancement additive for multicomponent filaments - 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 one of the polymeric components in order to accelerate its solidification rate. The additive enhances crimp, allows for highly crimped filaments to be made at smaller deniers, and produces low density webs with improved stretch and cloth-like properties. Specifically, the additive incorporated into the filaments is a nonionic surfactant such as an alkyl ether alkoxylate, a siloxane alkoxylate, an ester of a polyalkylene glycol, a polysaccharide derivative, a glycerol ester, or mixtures thereof.

Description

ADDITIVE OF CURLY INCREMENT FOR FILAMENTS OF MULTIPLE COMPONENTS Field of the Invention The present invention is generally directed to filaments of multiple components bonded with yarn and non-woven fabrics made of the filaments. More particularly, the present invention is directed to incorporating an additive one of the polymers used to make the multiple component filaments. The additive increases curl, smaller perimeters, generally simplifies the process to naturally curl the filaments, and produces fabrics with stretch properties and cloth-type improvements. in particular, the additive incorporated in the filaments is non-ionic surfactant.

Background of the Invention Non-woven fabrics are used to make a variety of products which desirably have particular level of softness, strength, uniformity, liquid handling property such as absorbency, and other physical property. Such products include towels, industrial cleaning cloths, incontinence products, filter products, infant care products such as baby diapers, absorbent women's care products, and garments such as clothing doctor. These products are often made from multiple layers of non-woven fabrics to obtain the desired combination of properties. For example, disposable b diapers made of polymeric non-woven fabrics can include a porous, soft lining layer which adjusts close to the baby's p, a waterproof outer shell which is strong and soft, and one or more layers of liquid handling interio which are soft, voluminous and absorbent.

Non-woven fabrics such as the above commonly do by spun bonded thermoplastic materials. Such fabrics are called yarn bonded materials. Spunbonded nonwoven polymeric fabrics typically make thermoplastic materials by extruding the thermoplastic material through a spinner organ, attaching a stream of air at high velocity to the extruded material in filaments to form a random fabric on a collector surface.

Spunbonded materials with desirable combinations of physical properties, especially combinations of softness, strength and absorbency, are produced but limitations have been encountered. 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 non-woven materials having desirable combinations of physical properties, non-woven polymer fabrics made of bicomponent or multi-component filament fibers have been developed. The filaments or polymeric fibers of multiple or bicomponent components include two or more polymeric components which remain distinct. As used herein, the filaments mean continuous threads of material and half-cut fibers or discontinuous threads having a defined length. first and the subsequent components of the multiple component filaments are arranged in essentially different areas through the cross section of the filaments extending continuously along the length of the filaments. Typically, one component exhibits properties different from the others so that the filaments exhibit properties of the two components. For example, a component may be polypropylene which is relatively strong and another component may be polyethylene which is relatively soft. The final result is a strong non-woven fabric per soft.

To increase volume or fill it with two-component non-woven fabrics to improve fluid handling performance or to increase the "cloth-like" feel of fabrics, Filament or bicomponent fibers are often crimped. The bicomponent filaments may be either mechanically crimped or, if appropriate polymers are used, curl naturally. As used herein, naturally curled filament is a filament that is crimped by activating a latent curl contained in the filaments. For example, in one embodiment, the filaments can naturally be curled by subjecting the filaments to a gas, such as a heated gas, after having been 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. However, difficulties have been experienced in the heavy pa to produce filaments that will naturally curl to the extent required for the application. particular.

Also, in the past, it was usually necessary to naturally curl the filaments of multiple components through the contact of the filaments with the heated air. In particular, it was typically necessary to heat the air temperatures as high as 350 ° F in order to activate latent curing present within the filament. Unfortunately heating a gas at such high temperatures essentially increases the energy requirements of the process. It would be particularly desirable if Multiple component filaments could be naturally curled without having to be exposed to a stream of heated gas.

As such, there is currently a need to produce multi-component filaments with increased natural curl properties. Also, there is 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 others of the prior ar constructions and to the methods.

Therefore, it is an object of the present invention 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 making them economically.

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 crimping 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 multicomponent filaments.

It is another object of the present invention to provide a method for naturally curling multiple component filaments by adding to one of the filament components a rizad increase additive.

It is still another object of the present invention to provide a process for producing multiple component curled filaments in which a non-ionic surfactant has been added to one of the polymeric components used to make the filaments.

Another object of the present invention is to provide a process for naturally curling the multiple component filaments by exposing the filaments to a ga at room temperature.

These and other objects of the present invention are achieved by providing a process for forming a non-woven tea. The process includes the steps of melting the filaments of multiple components with spinning. Filaments of multiple components include a first polymer component and a second polymer component. The first polymeric compound has a faster solidification rate than the second polymeric component to provide the filaments with a latent ripple. According to the present invention, the first polymer component contains a curing enhancement additive. In particular, the riza enhancement additive is a non-ionic surfactant.

Once spunbond, the multiple component filaments are pulled and curled naturally. Then, the crimped filaments are formed into a woven fabric for use in various applications.

In one embodiment, the crimped increase additive may be, for example, a fatty alcohol ether. As used herein, a fatty alcohol refers to an alcohol having a carbon chain of 20 carbon atoms or less, particularly a carbon chain of 10 less carbon atoms. For example, an ether of a fatty alcohol may include alkyl ether alkoxylate.

Other nonionic surfactants which may be used in the present invention include siloxa alkoxylates and esters of polyalkylene glycols, such as the fatty acid ethers of polyethylene glycol or polypropylene glycol. Particular example of an ester of a polyalkylene glyc particularly suitable for use in the present invention is a polyethylene glycol monolaurate.

Additional examples of the ionic surfactants include the glycerol esters and the polysaccharide derivatives. For example, in one embodiment, the additive increase in curl can be a mixture of sorbitan monooleate and an alkoxylated castor oil, such as a hydrogenated and polyethoxylated castor oil.

Preferably, the first polymer component is polypropylene or a copolymer containing primary polypropylene. The second polymer component, on the other hand, can be polypropylene, polypropylene copolymers, polyethylene polyethylene copolymers.

In general, the curly increase additive of the present invention can be added to the first polymeric composite in an amount of up to about 5% by weight, particularly from about 0.5% to about 5% by weight. In a preferred embodiment, the ripple increment additive is added to the first polymer component in an amount from about 1.5 to about 3.5% by weight.

Once present, the curly increase additive causes the filaments to suffer a greater degree of natural ringlets. For example, filaments made according to the present invention will typically have at least 10 rhizards per inch, and particularly from about 15 rhizards per inch to about 25 rips per inch. A particular advantage, as opposed to the prior art constructions of the filaments of the present invention may be naturally curled without subjecting the filaments to a heated gas. Instead of this, the latent ripple present within the filaments can be activated simply by contacting the filaments with the air at room temperature during the formation.

These and other objects of the present invention are also achieved by providing a non-woven fabric made of multi-component crimped filaments linked with yarn. The curled filaments of multiple components make at least a first polymer component and a second polymer component. In particular, the polymer components are selected so that the first polymeric component has a faster solidification rate than the second polymer component. According to the present invention, the first polymer component has a curling enhancer aditi which comprises an ionic surfactant.

For example, in one embodiment, the crimped filaments may be bicomponent filaments which include a polypropylene component and either a second polypropylene component or a polyethylene component. The ionic surfactant may be added to the polypropylene component in an amount of up to about 5% by weight. The ionic surfactant may be, for example, an alkyl ether alkoxylate, siloxane alkoxylate, a polyalkylene glycol ester, glycerol ester, a polysaccharide derivative, or mixtures thereof.

Other objects, features and aspects 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 thereof, for one with ordinary skill in the art, is set forth m particularly in the rest of the description, including reference to the accompanying figures in which: Figure 1 is a schematic drawing of a process line for making a preferred embodiment of the present invention; Figure 2A is a schematic drawing illustrating the cross section of a filament made in accordance with the embodiment of the present invention with the 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 or incorporation of the present invention with the A and polymer components in an eccentric sheath / core arrangement.

The repeated use of the reference characters the present description and drawing is intended to represent the same or analogous elements or features of the invention.

Detailed Description of Preferred Additions It should be understood by one of ordinary skill in the art that the present discussion is a description of only example embodiments, and does not intend to limit the broader aspects of the present invention, the broader aspects of which are covered in the construction of example.

The present invention is generally directed to the multi-component filaments and yarn-bonded fabrics produced from the filaments. in particular, the filaments are naturally curled in, for example, a helical arrangement. The curling of the filaments increases the volume the softness, the drop and can increase strength of the non-woven fabrics made of the filaments. The non-woven fabrics also have improved fluid handling properties and have an increased cloth-like feel and appearance.

The multicomponent filaments for use in the present invention contain at least d polymeric components. The polymeric components may be, for example, in a side-by-side configuration or a sheath and eccentric core configuration. The polymeric components are selected from semi-crystalline polymers and crystalline thermoplastics which have different solidification rates with respect to each other so that the filaments undergo natural curling. In particular, one of the polymer components has a faster solidification rate than that of another polymeric component.

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

Although it is not known, it is believed that the latent ripple of the filaments of the multiple components is created in the filaments due to the differences in shrinkage properties between the polymeric components. In addition, it is believed that the main cause of the shrinkage difference between the polymer components is the incomplete crystallization of the slower polymerizing polymer during the fiber production process. For example, during the formation of the filaments when the fast solidifying polymer is solidified, the slow solidifying polymer is partially solidified it does not pull measurably longer and therefore does not additionally experience a significant orienting force. In the absence of a guiding force, the slow solid polymer does not additionally crystallize significantly as it is being cooled and solidified. Therefore, the resulting filaments possess the latent ripple and such latent ripple can be activated by subjecting the filaments to a process that allows a sufficient molecular movement of the polymer molecules from the slow solidifying polymer to facilitate further shrinkage and crystallization.

The present invention is directed to add ripple increase additive to one of the polymer components contained in a multi-component filament. The curly increase additive creates a greater potential amount of natural curl within the filament by creating or increasing the difference in the solidification rates between the polymeric components. In particular, it has been found that the curl enhancement additive of the present invention when combined with a polymer, causes the rate of solidification of the polymer to accelerate.

For example, in one embodiment, the bicomponent filaments can be constructed containing a polypropylene component and a polyethylene component. It is generally known that the polypropylene component will have faster solidification rates than the polyethylene component. According to the present invention, the additive d increase of ripple can be added to the polypropylene component d thereby further accelerating the solidification rate of the polypropylene. In this way, the difference between the solidification rates of the polypropylene and polyethylene becomes greater by creating filaments having increased latent ripple.

In addition to creating a greater difference between the solidification rates of the two polymeric components, the curly increase additive of the present invention can also be used to create the latent ripple in a filament that is made of two or more polymeric components that have same or similar solidification rates. For example, in alternate incorporation, the additive can be added to a bicomponent filament in which the first polymeric component and the second polymeric component are made of the same polymer. For example, in a bicomponent filament q containing a first polymer component made of polypropylene and a second polymer component also made of polypropylene, the ripple increment additive of the present invention can be combined with one of the components. When added to one of the polymeric components, the solidification rate of the polymer component increases, creating a difference in the solidification rate with the other polymeric component, thereby creating a latent ripple within the filament. Through this method, multicomponent filaments made exclusively of polymeric components that have all similar solidification rates can naturally be broken down instead of having to be mechanically crimped.

The curly increase additive of the present invention which has been found to increase the solidification rates of polymeric materials and which has also been found to be particularly well suited for use in spinning bonding processes, is generally directed to nonionic surfactants or a mixture of nionic surfactants that are compatible with the polymer melt. For example, examples of nonionic surfactants include fatty alcohol ethers, siloxane alkoxylates, polyalkylene glycol esters, glycerol esters, polysaccharide derivatives, and mixtures thereof.

For example, examples of the fatty alcohol ethers particularly include the alkyl ether alkoxylates, such as the alkyl ether ethoxylates and the alkyl ether propoxylates. A commercially available alkyl ethoxylate that can be used in the process of the present invention is the ANTAROX BL-21 surfactant marketed by Rhone-Pulenc of Cranbury, New Jersey. E surfactant ANTAROX BL-214 is a mixture of ethoxylated and propoxylated C8 to CI alcohols.

A siloxane alkoxylate is a silicone surfactant that includes ethoxylated siloxanes and propoxylated siloxanes. An example of a commercially available silico surfactant that can be used as the curl enhancement additive of the present invention is the MASIL SF 19 surfactant marketed by PPG Industries, Inc., of Gurne Illinois.

Another class of compounds that can be used as the curl enhancement additive of the present invention include the esters of polyalkylene glycols, and particularly the fatty acid esters of polyethylene glycol and polypropylene glycol. For example, fatty acids that can be combined with polyalkylene glycols include lauric acid, palmitic acid, stearic acid, and the like. For example, commercially available fatty acid ester of a polyalkyl glycol is MAPEG 400 ML sold by PPG Industries, Inc. of Gurnee, Illinois. MAPEG 400 ML is a polyethylene glycol monolaurate. Specifically, even when not critical to the present invention, MAPEG 400 ML is made with a polyethylene glycol having a molecular weight of about 400.

Other nonionic surfactants that can be used in the present invention include polysaccharide derivatives and glycerol esters. An example of a polysaccharide derivative, for example, is a sorbitan monooleate, while a glycerol ester may include, for example, an alkoxylated ring oil. A commercially available nonionic surfactant containing a mixture of sorbitan monooleate and a polyethoxylated hydrogenated castor oil is an AHCOVEL BASE N-marketed by ICI Americas, Inc., of Wilmington, Delawar.

As described above, it has been discovered that the nonionic surfactants mentioned above, when combined with the polymeric material, increase the solidification rate of the polymer. When added to multiple component filaments, the curly increase additive of the present invention can be used to create a latent ripple on a filament made of polymers that have similar solidification rates or that can be used to create larger amounts of latent ripple. in a polymer made filament having similar solidification rates or q can be used to create larger amounts of latent ripple in a filament made of polymers having different solidification rates.

In addition to creating multiple component filaments having a greater natural curl, it has been discovered that the curl increment 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 fluffiness and a lower density. By being able to make low density fabrics, less material is required to make the fabrics and the fabrics are therefore less expensive to produce. In addition to having lower densities, the fabrics have also found that they are more of a cloth type, to have a softer tac, to have more stretch, to have a better recovery and to have a better resistance to abrasion.

A further advantage of the curled increase additive of the present invention is that the additive allows the formation of multi-component filaments having relatively high natural curl while the same have a relatively low denier. As used herein, deni refers to the linear density of a filament. In the past it was very difficult to create filaments at low denier linear densities, such as less than 2, that had a relatively high natural ripple. In the past, the pull force used to produce low denier fibers usually prevented any significant latent ripple present in the filaments from being removed. The filaments made according to the present invention, on the other hand, can have more than 10 crimps per inch to deniers lower than 2, and even lower than 1.2.

As described above, the fabric of the present invention includes polymer filaments of continuous multiple components comprising at least the first and second polymer components. A preferred embodiment of the present invention is a polymeric fabric that includes the continuous bicomponent filaments comprising a first polymeric component A and a second polymer component B. The bicomponent filaments have a cross section, or length, and a peripheral surface. The first second components A and B are arranged in essentially distinct areas across the cross section of the bicomponent filaments and extend continuously along the length of the bicomponent filaments. The second component B constitutes at least a 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 and be a side-by-side arrangement, as shown in Fig. 2A or in an eccentric sheath / core arrangement co shown in Fig. 2B so that the resulting filaments exhibit a natural helical curling The polymer component A is the core of the filament and the polymer component B is the sheath in the sheath / core arrangement. The methods for extruding the multiple component polymer filaments into such arrangements are well known by those of ordinary skill in the art.

A wide variety of polymers are suitable for practicing the present invention. Preferably, the polymers chosen to build the filaments according to the present invention are the polyolefins, such as polyethylene and polypropylene. For most applications, the ripple increase aditi of the present invention is added polymer component A as described above. Furthermore, it was found that the ripple increase additive must be added to the polypropylene or to a copolymer containing polypropylene.

Thus, in one embodiment, the polymer component may comprise polypropylene or a random copolymer containing polypropylene, such as a propylene and butylene copolymer.

The polymer component B, on the other hand preferably comprises polyethylene such as linear low density polyethylene and high density polyethylene, polypropylene, or a random copolymer of propylene and ethylene. Of particular advantage, the polymer component A and polymer component B can be made of the same polypropylene polymer and, by adding the curled increase additive to one of the components, a filament q having a natural ripple can be formed.

Suitable materials for preparing the multi-component filaments of the present invention include the polypropylene ESCORENE PD-3445 available from Exxon Houston, Texas, the random copolymer of propylene and ethyle available from Exxon, the polyethylene ASPUN 6811A, XU 61800 and 25 available from Dow Chemical Company of Midland, Michigan, high density polyethylene 25355 and 12350 available from D Chemical Company.

When polypropylene is component A and polyethylene or polypropylene is component B, the bicomponent filaments may comprise from about 20 about 80% by weight of component A and from about 20 to about 80% of the component B. More preferably, the filaments comprise from about 40 to about 60% by weight of component A and from about 40 about 60% by weight of component B.

In order to combine the curly increase additive with a polymer component in an incorporation, polymer and the additive may be mixed and extruded together during the formation of the multicomponent filaments. In an alternate incorporation, the riza increment additive and the The polymer component can be mixed with a melt before being formed into the filaments of the present invention. For example, the polymer component and the additive can be extruded through a twin screw extruder and formed into pellets before being bonded with a melt. in filament The combination of the polymer component with the additive increase of curling prior to the formation of the filaments co described above can promote better mixing between the ingredients.

In general, the riza increase additive can be added to one of the polymer components in an amount of up to about 5% by weight. In particular, a preferred embodiment, the curl increase additive can be added to the polymer component A up to a quantity of from about 0.5% to about 5% by weight and particularly from about 1.5% to about 3. by weight. If too much of the additive is combined with polymer, the viscosity of the polymer may increase to the point where the polymer can not be effectively spun in filament and the filament breakage may occur.

A process for producing the multiple component filaments and the non-woven fabrics according to the present invention will now be discussed in detail with reference to Figure 1. The following process is similar to the process described in U.S. Patent No. 5,382,400, granted to Pike and others, which is incorporated herein by reference in its entirety.

Turning now to Figure 1, a process line 10 for preparing a preferred embodiment of the present invention is described. The process line 10 is arranged to produce continuous bicomponent filaments but it should be understood that the present invention comprises non-woven fabrics made with multicomponent filaments that have more than two components. For example, the fabric of the present invention can be made with filaments having three or four components.

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

The spinning organs for extruding the bicomponent filaments are well known to those with ordinary skill in the art and therefore are not described here in detail. Generally described, the spinner 18 includes a box containing a spin pack which includes a plurality of plates stacked one on top of the other with a pattern of openings arranged to create flow paths for directing the polymer components and B separately through the spinner organ. The spinner body 18 has openings arranged in one or more rows. The openings of the spinning member form a curtain extending downwards of filaments when the polymer s are extruded through the spinning member. For the purposes of the present invention, the spinner member 18 may be arranged to form side-by-side or eccentric sheath / nub bicomponent filaments illustrated in Figures 2A and 2 The process line 10 also includes a cooling blow 20 positioned on one side of the filament curtain extending from the spinner member 18. The air from the cooling air blower 20 cools the filaments extending from the spinner member 18. The cooling air can be directed from one side of the curtain of filaments co shown in figure 1 or from both sides of the curtain filaments.

An aspirator or fiber pulling unit 22 is placed below spinning organ 18 and receives the cooled filaments. The suction units or fiber pulling units for use in melt spinning polymers are well known as discussed above. The fiber pulling units for use in the processes of the present invention include linear fiber aspirator of the type shown in US Pat. No. 3,802,817 and eductiv guns of the type shown in the United States of America patents. 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 conduit through which the filaments are pulled by sucking the air from the sides of the conduit and flowing down through the conduit. A blower or heater 24 supplies suction air to the fiber pulling unit 22. The suction air pulls the filaments and the ambient air through the fiber pulling unit.

A perforated and endless forming surface is positioned below the fiber pulling unit 22 and receives the continuous filaments from the outlet opening of the fiber pulling unit. The forming surface 26 travels around the guide rollers 28. A vacuum 30 is placed below the forming surface 26 where the deposited filaments pull the filaments against the forming surface.

The process line 10 further includes a junction apparatus such as thermal point attachment rollers (shown in phantom) or an air via linker 36. Air-through connectors and thermal point joiners are known m those with ordinary skill in the art are not described here in detail. Generally described, air joiner 36 includes a perforated roller 38, which receives the tissue, and a cover 40 surrounding the perforated rodil. Finally, the process line 10 includes a winding roll 42 for taking the finished fabric.

To operate the process line 10, the hoppers 1 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 conduits 16a and 16b and the spinning organ 1 In accordance with the present invention, the polymer component A preferably contains the curly increase additive of the present invention. As described above, the aditi can be mixed with the polymer as it is fed through the extruder 12a or the polymer can be premixed with the additive. Although the temperatures of melted polymers vary depending on the polymers used, when used, polypropylene and polyethylene as the component at the preferred temperatures of the polymers when extruded vary from about 370 ° F to about 530 °. F, preferably ranging from 400 ° F to about 450 ° F.

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

After cooling, the filaments are pulled to the vertical conduit of the fiber pulling unit by means of the flow of a gas, such as air, from the heater to the blower 24 through the fiber pulling unit. The fiber pulling unit is preferably placed 30 to 60 inches below the bottom of the spinning member 18.

In the past, in order to activate the latent ripple of a filament, the temperature of the air supplied from heater 24 has to be heated to temperatures generally greater than 170 ° F and particularly to temperatures around 350 ° F. It has unexpectedly been discovered, however, that by adding the curl increment additive of the present invention to a multicomponent filament, it is no longer necessary to contact the filament with a heated gas stream so that the filament is curled. naturally. Instead, it has been found that the latent ripple of the filaments constructed in accordance with the present invention can be activated merely by contacting the filaments with a stream of gas, such as air, at room temperature, as at temperatures as low as around 60 ° F or even lower. Therefore, when filament containing the ripple increase additive is processed, the heating 24 is no longer required and the energy requirements for producing the crimped filaments are essentially reduced.

If desired, however, the air that has contact with the filaments can still be heated. In some applications, if the air is heated, even when not necessary, a greater degree of curling may occur. In this aspect, the heater 24 air temperatures may be varied in order to achieve different curling levels.

The ability to control the degree of curling of the filaments is particularly advantageous because it allows one to change the resulting density, the pore size distribution and the fabric drop by simply adjusting the air temperature in the pulling unit. fibr The crimped filaments are deposited through the outlet opening of the fiber pulling unit 22 to the moving forming surface 26. The vacuum 20 pulls the filaments against the forming surface 26 to form a non-woven and disbonded filament fabric continuous If necessary, the fabric is then lightly compressed by means of a compression roller 32 and then joined to the thermal point p by the rollers 34 or joined by air in the jointer via air 36.

In the air-binding unit 36 as shown in FIG. 1, air having a temperature above the temperature of component B and equal to or below the melting temperature of component A is directed from cover 40, through tissue , and up to the perforated roller 38. The hot ai melts the polymer component B and therefore for bonds between the bicomponent filaments to integrate the fabric. When polypropylene and polyethylene are used with the polymer components, the air flowing through the junction through air preferably has a temperature which varies from about 230 ° to about 280 ° F and from a rate of around 100 to about 500 feet per minute. The residence time of the fabric in the joiner 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 winding roll 42 and is ready for further use or treatment. When used to make liquid absorbent articles, the fabric of the present invention may be treated with conventional surface treatments or may contain conventional polymer additives to increase fabric wetting. For example, the fabric of the present invention can be treated with polyalkylene oxide modified siloxanes and xylans such as polyalkylene oxide modified polydimethyl siloxa as described in U.S. Patent No. 5,057,361. T surface treatment increases fabric wetting.

With the present invention, however, it was discovered that the surfactant additive also serves as a wetting agent for the bonded fabric. Therefore, the fabric makes aqueous liquids naturally wettable. Therefore, a further treatment may not be necessary. In addition, if t subsequent treatment is desired, the characteristics of the original tissue moistening will facilitate the subsequent treatment process.

When joined by air, the fabric of the present invention characteristically has a relatively high sponge. The helical curling of the filaments cr an open tissue structure with essentially hollow parts between the filaments and the filaments are joined at contact points. The air-bonded fabric of the present invention typically has a density of from about 0.015 g / cc to about 0.040 g / cc and a basis weight of about 0.25 to about 5 ounces per square yard and preferably from about about 1.0 to about 3 ounces per square yard.

Filament denier generally ranges from 1.0 to about 8 denier per fiber. As discussed above, the curl increment additive of the present invention generally allows the production of highly crimped denier filaments. In the past, naturally curly denier filaments were difficult if impossible to produce. Therefore, according to the present invention, filaments having a natural curl of less than about 10 crimps per inch can yield deniers of less than 2, and particularly to deniers of less about 1.5. For most non-woven fabrics, it is preferable that the filaments have from about crimps per inch to about 25 crimps per inch.

The thermal point joint can be conducted in accordance with the United States of America patent No 3,855,046, the disclosure of which is incorporated herein by reference When it is attached to a thermal point, the fabric of the present invention exhibits a more cloth-like appearance and, for example, is useful as an outer covering for items for personal care or as a garment of material.

Although the joining methods shown in FIG. 1 are thermal point attachment and air binding, it should be understood that the fabric of the present invention can be joined by other means such as furnace bonding, ultrasonic bonding, hydroentanglement or the combinations thereof. Such joining techniques are well known to those with ordinary skill in the art and are not discussed here in detail.

Although the preferred method for carrying out the present invention includes contacting the filaments of multiple components with the aspirating air, the present invention encompasses other methods of activating the latent helical curl of the continuous filaments before the filaments are formed. in a tissue. For example, multi-component filaments may be contacted with air after cooling but upwardly of the aspirator. In addition, the filaments of multiple components can be brought into contact with the air between the vacuum cleaner and the tissue-forming 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 applications. For example, fabrics can be used in filter products, in liquid absorbent products, in personal care articles, in garments and in various other products.

The present invention can be understood better with reference to the following examples: EXAMPLE No. 1 A bicomponent filament fabric bonded with yarn having a basis weight of 2.6 ounces per square yard was produced according to the process described in U.S. Patent No. 5,382,400 issued to Pike and others. The bicomponent filaments used for making the fabric include a polyethylene component and a polypropylene component in a side-by-side configuration. The polyethylene used to make the filaments was ASPUN XU6180 obtained from Dow Chemical.

The polypropylene used to make the filament on the other hand, was ESCORENE 3445 obtained from Exxon Corporation and which contained 2% by weight of Ti02. In accordance with the present invention, polypropylene also contained 2.5% by weight d MASIL SF-19 nonionic ethoxylate siloxane surfactant obtained from PPG Industries. The non-ionic surfactant was added polypropylene according to the present invention to act as a curly increase additive.

The polypropylene component and the polyethylene component were fed to separate extruders. The extruded polymers were spun into bicomponent round filaments using a spinning die having 50 p-holes.

From the spinning die, the filaments were fed through a fiber pulling unit at a pulling pressure of 3.5 pounds per square inch and at a production of 0.5 ghm. The resulting filaments had denier of 2.1 denier per fiber. The fibers were pulled p air at 3.5 pounds per square inch and at 65 ° F. From a particular sale, while the filaments were being pulled the air at a temperature of only 65 ° F triggered the curling beating and caused the filaments to become highly crimped.

The pulled filaments were deposited on a perforated surface to form a non-woven fabric which was passed through a jointer through air at a temperature of 255 ° F. The resulting fabric had a density 0.024 grams per cubic centimeter and was found to be instantaneously wettable with water.

A similar process was also used to form the bicomponent filaments that did not contain the additive ripple increment of the present invention. Such filaments did not achieve any curling when contacted with air in the fiber pulling unit at about my temperature as described above. In addition, the fabric made the filaments did not have as much fluffiness as the above-mentioned fabric made according to the present invention.

EXAMPLE No. 2 The process for making the bicomponent filaments and for manufacturing the filament non-woven fabric as described in Example 1 was repeated. In this example, however, instead of using the non-ionic surfactant, MASIL S 19, the ANTAROX BL-214 obtained from Rhone-Poulenc was used. ANTAROX BL-214, which is an alkyl ether ethoxylate, was added to the polypropylene component in an amount of 3% by weight.

During the process, the pull pressure of fibr was 3 pounds per square inch, the polymer production was 0.5 ghm, and the temperature of the bonding device through air was 250 ° F. During pulling, the filaments were placed in contact with air at a temperature of only about 54 ° F in order to curl the filaments. The filaments were pulled to denier size of about 2.2.

The resulting fabric had a basis weight of 3.5 oz per square yard and a density of 0.020 grams per cubic centimeter.

Similar to the fabric made in the Example, the non-woven fabric made with ANTAROX BL-214 was found to have a superior fluffiness and was instantly wettable with water. It was also observed that the bicomponent filaments became highly crimped when subjected to air at a temperature of only 54 ° F. Thus, this example further demonstrates that heated air is not required to activate latent ripple present within the filaments.

EXAMPLE No. 3 The process described in Example 2 was repeated. In particular, the polypropylene component again contained 3 by weight of nonionic surfactant ANTAROX BL-214. In opposition to Example No. 2, however, the production of the polymer through the spin pack was 0.4 ghm.

In this example, the filaments had a deni of 1.7, while the resulting fabric had a basis weight of 3 ounces per square yard and a density of 0.021 grams p cubic centimeter. Again, a nonwoven fabric c was produced a substantial amount of fluffiness and which was instantly wettable with water. In this example it was also discovered that low denier filaments can be produced according to the present invention which can be highly crimped merely by subjecting the air filaments to about room temperature.

EXAMPLE No. 4 The procedure for producing the filaments and the non-woven fabrics described in Example No. was repeated. In this example, instead of using the non-ionic surfactant MAS SF-19, a mixture of MAPEG 400 ML obtained from P Industries and from ANTAROX BL-214 to the polypropylene component in an amount of 3% by weight and a proportion by weight of 1: MAPEG 400 ML contains the polyethylene glycol monolaurate.

The polymer filaments were pulled at a production of 0.5 ghm and at a pressure of 2 pounds per square inch.

The filaments produced had a denier of approximately 2.3. During the pulling process, the filaments were subjected to ambient air in order to activate latent ripple. The filaments became highly curled during the process.

The non-woven fabric made of the filaments had a density of about 0.025 grams per cubic centimeter. observed that the non-woven fabric had a high fluffiness.

EXAMPLE No. 5 The process for producing the filaments and fabrics described in Example No. 4 given above was repeated using in this example, as a curly increase additive, or mixture of AHCOVEL Base N-62 obtained from ICI Americas, Inc., which is a mixture of sorbitan monooleate and polyethoxylated hydrogenated castor oil, and ANTAROX BL-214. The mixture was added to the polypropylene component in an amount of 3% by weight. The AHCOVEL Base N-62 and the ANTAROX B 214 were added in equal proportions.

In order to curl the filaments, the filaments were placed in contact with the air at a temperature of approximately 64 ° F while they were being pulled. In contact with the air, the filaments became highly dense. The filaments produced had a denier of approximately 2.3.

The filaments spun nonwoven fabric your a density of 0.030 grams per cubic centimeter and contained a substantial amount of fluffiness.

EXAMPLE No. 6 The following example was carried out in order to demonstrate that in addition to the polypropylene / polyethylene filaments, the curly increase additive the present invention can also be used in polypropylene / polypropylene filaments.

The polypropylene / polypropylene bicomponent filaments were made in a similar manner as described in Example 1. Specifically, the bicomponent filaments were made of polypropylene containing 2% by weight of Ti02. According to the present invention, the non-ionic alkyl ethoxylate surfactant ANTAROX BL-214 was added to one side of the filament in an amount of 3% by weight.

The side filaments were produced by using a 20-hole fiber spin pack.

Polymer production through the spin pack was 0. ghm. The filaments were pulled to a pressure mark at 75 using a Lurgi Gun. During the pulling, the filaments were brought into contact with the air at room temperature which caused the filaments to curl. The loose tissues of high fluff were obtained from the filaments.

The bicomponent polypropylene / polypropylene filaments were similarly produced not containing the nonionic surfactant ANTAROX. In opposition to the filaments described above, the bicomponent filaments that do not contain the nonionic surfactant suffered no substantive ripple when contacted with the air during pulling. The filaments also produce flat tissues.

These and other modifications and variations of the present invention may be practiced by those with ordinary skill in the art without departing from the spirit scope of the present invention which is more particularly set forth in the appended claims. Furthermore, it should be understood that the aspects of the various additions can be exchanged both in whole and in part. In addition, those of ordinary skill in the art will appreciate that the foregoing description is given by way of example only and that limiting the invention so described in such appended claims is intended.

Claims (30)

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

1. A process for forming a non-woven fabric comprising the steps of: spinning the multicomponent filaments d, said filaments comprise a polymeric first component and a second polymeric component, said first polymer component has a faster solidification rate than that of the second polymeric component, said polymeric component contains a curd increase additive. said curl increase additive comprises a nonionic surfactant; pulling said multi-component filaments naturally curling said filaments of multiple components; Y then forming said multiple component filaments into a nonwoven fabric.

2. A process as claimed in clause 1, characterized in that said nonionic surfactant comprises an ether of a fatty alcohol.

3. A process as claimed in clause 1, characterized in that said nonionic surfactant comprises an alkyl ether alkoxylate.

4. A process as claimed in clause 1, characterized in that said nonionic surfactant comprises a siloxane alkoxylate.

5. A process as claimed in clause 1, characterized in that said nonionic surfactant comprises an ester of a polyalkylene glycol.

6. A process as claimed in clause 1, characterized in that said nonionic surfactant comprises a mixture of a glycerol ester and a polysaccharide derivative.

7. A process as claimed in clause 6, characterized in that said glycerol ester comprises an alkoxylated castor oil and said polysaccharide derivative comprises sorbitan monooleate.

8. A process as claimed in clause 1, characterized in that said polymer component comprises polypropylene and said second polymer component comprises polypropylene.

9. A process as claimed in clause 1, characterized in that said first polymer component comprises polypropylene and said second polymer component comprises polyethylene.

10. A process as claimed in clause 1, characterized in that said nonionic surfactant added to said first polymer component in an amount up to about 5% by weight.

11. A process for forming a non-woven fabric comprising the steps of: spinning the bicomponent filaments said bicomponent filaments comprise a first polymeric component and a second polymer component, said polymeric first component comprises polypropylene mixed with ripple increase additive, said ripple increase additive comprises a non-ionic surfactant, said second component polymeric comprises a material selected from the group consisting of polypropylene and polyethylene; pulling said bicomponent filaments; crimping said bicomponent filaments; and then forming said bicomponent filaments into a non-woven fabric.

12. A process as claimed in clause 11, characterized in that said nonionic surfactant comprises a material selected from the group consisting of alkyl ether alkoxylate, a siloxane alkoxylate, a polyalkylene glycol d ester, a glycerol ester, a polysaccharide derivative and mixtures thereof.

13. A process as claimed in clause 11, characterized in that said nonionic surfactant comprises a polyethylene glycol monolaurate.

14. A process as claimed in clause 11, characterized in that said nonionic surfactant comprises a mixture of sorbitan monooleate and an alkoxylated castor oil.

15. A process as claimed in clause 11, characterized in that said non-ionic surfactant is present within said first polymeric component in an amount of from about 0.5% to about 5% by weight

16. A process as claimed in clause 11, characterized in that said non-ionic surfactant is present within said first polymer component in an amount of from about 1.5% to about 3.5% by weight.

17. A process as claimed in clause 11, characterized in that said crimped bicomponent filaments contain at least 10 crimps per inch.

18. A nonwoven fabric comprising crimped filaments of multiple components linked with spinning, dich curled filaments of multiple components are made of at least a first polymer component and a second polymeric component, said first polymer component has a faster solidification rate than that of the polymer component. second polymeric compound, said first polymer component contains ripple increase additive, said ripple increase additive comprises a non-ionic surfactant.

19. A non-woven fabric as claimed in clause 18, characterized in that said non-ionic surfactant comprises a material selected from the group consisting of alkyl ether alkoxylate, a siloxane alkoxylate, an ester of a polyalkylene glycol, a glycerol ester , of polysaccharide derivative, and mixtures thereof.

20. A non-woven fabric as claimed in clause 18, characterized in that said multiple bicomponent filaments bonded with yarn are naturally curled.

21. A non-woven fabric as claimed in clause 18, characterized in that said first polymeric component comprises polypropylene and said second polymeric component comprises a material selected from the group q consisting of polypropylene and polyethylene.

22. A non-woven fabric as claimed in clause 18, characterized in that said non-ionic surfactant is present in said first polymeric component in an amount of from about 0.5% to about 5% by weight

23. A nonwoven fabric comprising crimped multiple component filaments with spinning, said curled filaments of multiple components at least include a first polymer component and a second polymeric component, said first polymer component comprising polypropylene mixed with a curl increase additive said Rising increase additive comprises a material selected from the group consisting of alkyl ether alkoxylate a siloxane alkoxylate, an ester of a polyalkylene glycol, or glycerol ester, a polysaccharide derivative, and mixtures thereof, said second polymer component comprising a material selected from the group consisting of polyethylene polyethylene.

24. A non-woven fabric as claimed in clause 23, characterized in that said crimping increment additive is present in said first polymeric component an amount of from about 0.5% to about 5% p weight.

25. A non-woven fabric as claimed in clause 23, characterized in that said crimping increment additive comprises an alkyl ether alkoxylate.

26. A non-woven fabric as claimed in clause 23, characterized in that said crimping increment additive comprises a siloxane alkoxylate.

27. A non-woven fabric as claimed in clause 23, characterized in that said curling increment additive comprises a mixture of sorbitan monooleate and alkoxylated castor oil.

28. A non-woven fabric as claimed in clause 23, characterized in that said fabric has a basis weight of from about 0.5 ounces per square yard about 5 ounces per square yard, has a density from about 0.02 grams per cubic centimeter to about 0.03 grams per cubic centimeter, and where dich multifunctional filaments are have a denier of less than 5 have at least 10 crimps per inch.

29. A natural-bicomponent bicomponent filament comprising at least a first polymer component and a second polymer component, said first polymer component comprises polypropylene mixed with ripple increase additive, said ripple increase additive comprises a non-ionic surfactant, said second component make up polymeric it comprises a material selected from the group q consisting of polypropylene and polyethylene, said multi-component filament having a denier of less than about and having at least 10 crimps per inch.

30. A bicomponent filament naturally ripples as claimed in clause 2 characterized in that said nonionic surfactant comprises material selected from the group consisting of an alkyl ether alkoxylate, a siloxane alkoxylate, a polyalkylene glycol ester, a glycerol ester, a polysaccharide derivative, and mixture thereof. SUMMARY Multiple component filaments bonded with yarn and non-woven fabrics made from these filaments are described. In accordance with the present invention, the multicomponent filament contains a curled increase additive. Specifically, the ripple increase additive added to one of the polymer components in order to accelerate its solidification rate. The additive increases curl allows highly crimped filaments to be made to smaller deniers, and produces low density fabrics with improved drapery and cloth type properties. Specifically, the additive incorporated into the filaments in a nonionic surfactant such as an alkyl ether alkoxylate, a siloxane alkoxylate, a polyalkylene glycol ester, a polysaccharide derivative, or a glycerol ester or mixtures thereof.