MXPA00012818A - Cloth-like nonwoven webs made from thermoplastic polymers - Google Patents

Abstract

Extruded fibers and nonwoven webs made from the fibers are disclosed having improved cloth-like properties and an improved aesthetic appearance. The fibers used to form the webs are made from a thermoplastic polymer containing titanium dioxide and at least one mineral filler such as kaolin or calcium carbonate. In particular, the fillers are added in an amount so that the fillers become encapsulated within the polymeric material.

Description

NON-WOVEN CLOTHES OF CLOTH TYPE MADE OF THERMOPLASTIC POLYMERS Field of the Invention The present invention is generally directed to cloth-type non-woven fabrics. More particularly, the present invention is directed to a process for increasing the softness and decreasing stiffness of non-woven fabrics made of thermoplastic polymers and to a composition which produces softer fabrics with a low luster.

Background of the Invention Many woven and non-woven fabrics and other fabrics are formed of thermoplastic polymers such as polypropylene and polyethylene. For example, weaves er.laza? Cs with spinning, l s c "ale = be. For making diapers, disposable garments, personal care articles and the like, they are made by spinning a polymeric resin into fibers, such as filaments, then thermally bonding the fibers together. More particularly, the polymer resin is typically first heated to at least its softening temperature and then extruded through a spinner to form fibers, which may subsequently be fed through a fiber pulling unit. From the fiber pulling unit, the fibers are spread on a perforated surface where they are formed into a fabric of material.

In addition to fabrics bonded with spinning, other fabrics made of polymers include meltblown fabrics. The meltblown fabrics are made by extruding a polymeric material melted through a matrix to form fibers. As the fibers exit the matrix, a high pressure fluid, such as air or heated vapor, attenuates and breaks the fibers into discontinuous fibers of a small diameter. The fibers are randomly deposited on a perforated surface to form a fabric.

Spunbonded fabrics and meltblown fabrics have proven to be very useful for many different applications. In particular, fabrics are frequently used to build prod rc = liquid absorbers, diapers, women's hygiene products, and cleaning products. Non-woven fabrics are also useful for producing disposable garments, various hospital products, such as pads, curtains and covers for shoes and fabrics for recreation such as store covers. Even though they are very suitable for these applications, recently attention has been focused on the manufacture of non-woven fabrics plus type of cloth in order to avoid the feeling of type of ^ iü ?? htm plastic and gives appearance of such fabrics. The cloth, as opposed to plastic fabrics, has a more pleasing appearance and feel.

In the past, several attempts have been made to produce more cloth-like fibers of plastic materials in order to produce fibrous fabrics. For example, in U.S. Patent No. 4,254,182 issued to Yamaguchi et al., Polyester synthetic fibers are described as having an uneven and uneven random surface formed by microfine recesses and projections to provide more sense fibers. natural. The microfine projections and recesses are produced by incorporating in the f.hours silica in a size varying from 10 to 150 microns and in an amount, to produce surface projections. It has been taught that the surface projections increase, effectively the surface area of the fibers and concric ..yer. Friction-to-date, which reduces the plastic and polish sensation that is typically associated with plastic resins.

Prior art, however, merely teaches increasing the frictional characteristics of polymeric fibers in order to remove the plastic-like sensation of waxy plastics. There is still a need for ur. method that will alter the physical properties of the fibers so that the fabrics made of the fibers will feel more cloth-like and have other cloth-like characteristics. In particular, there is a need for fibrous fabrics other than cloth type and laminates made thereof from thermoplastic fibers that are less rigid and softer than conventionally made fabrics.

Definitions As used herein the term "non-woven fabric or fabric" means a fabric having a structure of individual fibers or threads which are interleaved, but not in an identifiable manner as a woven fabric. Fabrics or non-woven fabrics have been formed from many processes, such as, for example, meltblowing processes, spinning processes and carded and bonded weaving processes. The basis weight of the non-woven fabrics is usually expressed er. ounces of square cor- rective material are square corrals (gsm) and useful fiber diameters are usually expressed in microns. (Note that to convert from ounces per square yard to grams per square meter, you must multiply ounces per square yard by 33.91).

As used herein, the term "fibers bonded with yarns" refers to fibers of small diameter which are formed by extruding the molten thermoplastic material as filaments from a plurality of capillaries or usually circular and thin vessels of a spinner with the diameter of the extruded filaments then being rapidly reduced as indicated, for example, in U.S. Patent No. 4,340,563 issued to Appel et al., and in U.S. Patent No. 3,692,618 issued to Dorschner et al. , in the patent to the United States of America number 3,802,817 granted to Matsuki and others, in the patent to the United States of America No. 3,338,992 and 3,341,394 granted to Kinnery, in the patent of the United States of America number 3,502,763 granted to Hartman , in the patent of the United States of America number 3,502,538 granted to Levy, and in the patent of the United States of America America number 3,542,615 granted to Dobo and others. Yarn-bonded fibers are generally non-sticky when they are deposited on a collecting surface. Spunbonded fibers are generally continuous and have larger diameters of fibers, particularly between about 10 and 12 microns.

As used herein, the term "meltblown fibers" means fibers formed by extruding molten thermoplastic material through a plurality of fine matrix, usually circular, capillary vessels, such as strands or filaments fused into gas streams (eg. air) at high speed and converging which attenuate the filaments of molten thermoplastic material to reduce in diameter, which can be to a microfiber diameter. Then, the meltblown fibers are carried by the high velocity gas stream and are deposited on a harvester surface to form a meltblown fabric and randomly disbursed. Such a process is described, for example, in United States of America patent number 3, 84!), 241 granted to Butin. Melt-blown fibers are microfibers which may be continuous or discontinuous, are generally smaller than 10 microns in diameter, and are generally sticky and self-adhering when deposited on a collecting surface.

As used herein the term "polymers" generally includes but is not limited to homopolymers, copolymers, such as, for example, block, graft, random and alternating copolymers, atorpolymers, and so on, and mixtures and modifications thereof. "isr.es.

As used herein the term "machine direction" or MD means the length of a fabric in the direction in which it is produced. The term "cross machine direction" or CD means the width of the fabric, for example an address generally perpendicular to the machine direction.

As used herein the term "homopolymer fiber" refers to the fiber or part of a fiber formed from an extruder using only one polymer. This does not mean that fibers formed from a polymer are excluded, and that small amounts of color additives have been added., antistatic properties, lubrication, hydrophilicity, etc. These additives, such as, for example, titanium dioxide for coloring, are generally present in a quantity of 5 percent by weight and more typically around 2 percent by weight. The term "homopolymers" is also not meant to exclude a fiber formed from two or more extruders wherein both of the extruders contain the same polymer.

As used herein the term "bicomponent fibers" refers to fibers which have been formed from at least two extruded polymers of separate extruders but spun together to form a fiora. The bicompo floras are also sometimes menertheaded as multicomponent fibers. The polymers are different from one another even though the bicomponent fibers can be homopolymer fibers. The polymers are arranged in distinct zones placed essentially constant across the cross section of the bicomponent fibers and extend along the length of the bicomponent fibers. The configuration of such bicomponent fiber can be, for example, a pod / core arrangement where one polymer is surrounded by another or can be a side-by-side arrangement or an arrangement of "islands in the sea". The bicomponent fibers are shown in U.S. Patent No. 5,108,820 issued to Kaneko et al., In U.S. Patent No. 5,376,552 issued to Strack et al., And in European Patent No. 0586924. Two-component fibers, the polymers may be present in proportions of 75/25, 50/50, 25/75 or any other desired proportions.

As used herein the term "biconstituent fibers" refers to fibers which have been formed from at least two polymers extruded from the same extruder as a mixture. The term "mixture" is defined below. The biconstituent fibers do not have the various polymer components arranged in different zones placed relatively constant across the cross-sectional area of the fiber and the various polymers are usually non-continuous throughout the length of the fiber. The fiber, instead of this usually forming fibrils or protofibrils, which start and end at random, biconstituent fibers are sometimes also referred to as multi-constituent fibers, fibers of this type are generally discussed in, for example, the US Pat. No. 5,108,827 issued to Gessner The bicomponent and biconstituent fibers are also discussed in the text Polymer Compounds and Mixtures by John A. Manson and Leslie H. Sperling, copyright 1976 by Plemun Press, a division of Plenum Publishing Corporation of New York, IBSN 0-306-30831-2, pages 273 to 277.

As used herein the term "mixture" means a combination of two or more polymers while the term "alloy" means a subclass of mixtures wherein the components are immiscible but have been compatibilized. Miscibility and immiscibility are defined as mixtures that have positive and negative values, respectively, for the free energy of mixing. In addition, the "compatibilizaciór." it is defined as the process of modifying the interfacial properties of an immiscible polymer mixture in order to be an alloy.

Synthesis of the Invention.

The present invention recognizes and relates to the above disadvantages and shortcomings of the art of prior art constructions and methods.

Therefore, it is an object of the present invention to provide an improved composition for producing fibrous fabrics other than a thermoplastic polymer cloth type.

It is another object of the present invention to provide more cloth-type fibers, including filaments made of thermoplastic polymers.

It is another object of the present invention to provide non-woven fabrics other than cloth and laminates made thereof of thermoplastic polymers having stiffness and softness characteristics which are comparable with fabrics made of natural fibers.

Still another object of the present invention is to provide more cloth-like fibers, fabrics and laminates made of thermoplastic polymers by incorporating a mixture of fillers into the polymers.

Another object of the present invention is to provide the more cloth-type fibers, fabrics and laminates made of a pellet. This is made possible by incorporating into the polymer a mixture of mineral fillers such as calcium carbonate or kaolin clay and titanium dioxide.

These and other objects of the invention are achieved by providing a process for producing more non-woven fabrics of polymer fiber cloth with improved visual aesthetics. Cloth type properties are produced by incorporating a mixture of fillers into a thermoplastic polymeric material. The mixture of fillers includes titanium dioxide and mineral filler. Said mineral filler is preferably calcium carbonate or kaolin clay. Other mineral fillers that may be used in the process include talc, gypsum, diatomaceous earth, other natural and synthetic clays and mixtures thereof. Particular clays that can be used in the present invention in addition to kaolin include attapulgite clay, ventonite clay or morionite clay.

Once the fillers are incorporated into the thermoplastic polymeric material, the polymer is formed into fibers. The fibers are then subsequently used to create a non-woven fabric. The mixture of the fibers incorporated in the polymeric material is added in an amount sufficient to decrease the stiffness and increase the softness of the tissue in ccr.paraeiór. to ne woven fabrics made of thermoplastic polymeric raterial that do not contain any fillers.

In most applications, according to the present invention, the fibers are formed by extruding the thermoplastic polymeric material. For example, the non-woven tea may be made of meltblown fibers or fibers linked with yarn. The thermoplastic polymeric material used to make the fibers can be, for example, a polyolefin, a polyomide, such as a nylon, the polyester or a blend of the above-mentioned polymers, and copolymers of the above-indicated polymers such as the copolymers comprising the propylene units. In one embodiment, the thermoplastic polymer is polypropylene or a copolymer containing polypropylene.

The amount of the fillers added to the thermoplastic polymer material will generally decrease with the particular application. For most applications, the mineral filler should be added to the polymeric material in an amount of up to about 10 percent by weight, while the titanium dioxide can be added to the polymeric material in an amount of up to about 4 percent. cent by weight. More particularly, for most applications, the mineral filler will be added to the polymeric material in an amount of from about 2.5 percent by weight to about 5 per cent by weight after the titanium dioxide. It will be added in an amount of from about 1 percent by weight to about 2 percent by weight. In general, the fillers must be added to the polymer in an insufficient carton so that the fillers essentially protrude from the surface of the fibers. For example, the surface of the fibers should not be made rough due to the presence of the fillers.

In order to incorporate the fillers into the thermoplastic polymer, the fillers can be added to the polymer in combination with a carrier such as a low molecular weight wax. For example, in one embodiment, the vehicle may be a wax that is mixed with the fillers before being added to the polymeric material. The wax may be, for example, a polyethylene or polypropylene of low molecular weight and low density. The wax can be mixed with the fillers in an amount of about 50 percent by weight.

According to the present invention, it has been found that when a mineral filler in combination with titanium dioxide has been added to a thermoplastic polymer during the formation of non-woven fabrics, the fabrics have improved cloth type properties, an improved luster and less gloss. For example, it has been found that non-woven fabrics are softer and less rigid. The relievers also only minimally affect the strength and durability of the non-woven fabric or the fibers used to make the fabric. It has further been discovered that the fillers also improve the thermal aging stability of the fabric, which refers to the ability of the fabric to withstand the high temperatures for a long period of time without degrading.

These and other objects of the present invention are also achieved by providing fibers and fabrics made from the fibers. The fibers produced according to the present invention are designed to produce cloth-like fabrics useful for many diverse applications. The fibers are made of a thermoplastic polymer containing a mixture of fibers. The fillers include titanium dioxide and at least one mineral filler. The fillers are encapsulated within the thermoplastic polymer and are added in an insufficient amount to the fillers to protrude from the surface of the fibers.

The fibers produced can be discontinuous or continuous fibers and can be made according to the function blowing process or to a spinning bonding process.

Other objects, features and aspects of the present invention will be discussed in more detail below.

Detailed restriction of him? preferred additions It should be understood by one or with an ordinary skill in the art that the present discussion is a description of example embodiments only, and is not intended as limiting the broader aspects of the present invention, whose broader aspects are involved in the example construction.

In general, the present invention is directed to cloth-type fabrics made of thermoplastic polymers and to a process for producing the fabrics. Non-woven fabrics are made of thermoplastic polymer fibers. According to the present invention a mixture of fillers is incorporated into the thermoplastic polymer that is used to make the fibers. The mixture of fillers not only makes the non-woven fabrics made of the fibers look like cloth, but also provides non-woven fabrics with cloth-like properties.

In particular, the admixture of the fillers added to the thermoplastic polymer has been found to produce non-woven fabrics that are softer and less rigid than the fabrics made of polymers that do not contain fillers. In addition to being softer and less rigid, it has been found that non-woven fabrics also have improved thermal stability, which refers to the ability of the fabric to withstand high temperatures for extended periods of time without degrading. It is believed that fillers, in some applications, can also make the absorbent absorbent. In addition, it has been found that fillers do not adversely affect the strength of the fabrics, the durability of the fabrics, and the bonding characteristics and fiber-side characteristics of the polymer.

Non-woven fabrics made according to the present invention can be used in many different applications. For example, non-woven fabrics are very suitable for use in such products as diapers, women's hygiene products, wipes, towels, industrial garments, medical garments, medical covers, medical gowns , shoe covers, sterilization wraps, and various other products. These base fabrics can be used alone or can be combined with other fabrics to form laminates. In a preferred embodiment of the present invention, non-woven fabrics are used as face fabrics for diapers and personal care articles. It should be understood, however, that the items listed above are merely exemplary and that the basic fabrics may be used in several other applications.

The mixture of fillers that is incorporated into a ceramic plating according to the present invention is a combination of titanium dioxide and at least one mineral filler. The mineral filler is preferably kaolin clay (which contains an aluminum silicate hydroxide), calcium carbonate, talc, clay, attapulgite (which contains magnesium aluminum hydrate silicate). It is believed, however, that many other mineral fillers may be used in the present invention including, for example, synthetic clays. A unique mineral filler or combination of mineral fillers can be combined with titanium dioxide and can be incorporated into the polymer. Commercially available kaolin based materials can be used in the process of the present invention and include ECC 90, ECC 195, ECC 360 and ECC A-TEX 501 Ultra, which are all available from ECC International of Sandersville, Georgia. The ECC 90 is a delaminated kaolin of 0.45 microns while the ECC 195 and ECC 360 have an average particle size of 0.25 microns and 0.45 microns, respectively. The ECC A-TEX 501 Ultra, which has shown the best results until - here, is an anhydrous kaolin with an average particle size of about 0.2 microns. The ECC A-TEX 501 Ultra is virtually moisture free.

Other commercially available kaolin materials include MIRAGLOSS 91 and ULTRAGLOSS 90, the coils are available from Engelhard Corporation of Iselin, New Jersey.

ANSILEX 93, which is also commercially available from Engelhard Corporation. The ANSILEX 93 is a calcined kaolin with 90 percent of the particles having ur. size of less than 2 microns.

Commercially available calcium carbonate products that can be used in the process of the present invention include: MAGNIUMGLOSS, available from Mississippi Lime Company of Genevieve, Missouri; ALBAGLOSS available from Specialty Minerals, Inc. of New York, New York; and OMYACARB available from OMYA, Inc, of Proctor, Vermont. In particular, the MAGNIUMGLOSS calcium carbonate has an aragonite structure, the calcium carbonate ALBAGLOSS has a calcite structure, while the OMYACARB is a surface treated and beneficiated calcium carbonate.

An example of a commercially available attapulgite clay that can be used in the present invention is ATTAGEL 50 which is marketed by Engelhard Corporation. ATTAGEL 50 has an average particle size of about 0.1 microns and experiences about 12 percent by weight loss at 105 ° C.

In general, the mineral filler used in the present invention can have various particle sizes and morphologies. As a particular advantage, it has been discovered that the properties of the fibers made according to the present invention can be varied by varying the type of mineral filler used. In this form, a particular mineral filler may be chosen having a selected particle size and morphology to produce fibers and fabrics having desired characteristics.

The amount of mineral filler and titanium dioxide added to the polymeric material in the production of fibers and fabrics according to the present invention may also vary. Preferably, however, the filler mixture must be added to the polymeric material in an amount such that the fillers are encapsulated within the fibers made of the polymeric material. In other words, the fillers should not protrude essentially from the surface of the fiber formed from the polymer. In general, the amount of aggregate will depend on the particular fillers used, the morphology of the fillers, the particle size of the fillers, the dernier of the fibers formed, as well as several other factors.

For most applications, the mineral filler may be added to the polymer an amount of from about 0.1 percent to about 10 percent by weight. More particularly, the mineral filler can; be added in an amount of from about 2.5 percent to about 5 percent by weight.

On the other hand, the amount of titanium dioxide added to the polymeric material according to the present invention can vary from about 0.5 percent to about 4 percent by weight, and particularly from about 1 percent around of 2 percent by weight. One of the primary purposes for adding titanium dioxide to polymeric material according to the present invention is not only to improve the physical properties of the resulting fabrics and fibers but also to produce fabrics that have a more cloth-like appearance. Specifically, it has been discovered that titanium dioxide can remove the bright appearance that is normally associated with polymeric fabrics. Therefore, for most applications, titanium dioxide must be present in an amount sufficient to improve the visual appearance of the fibers and fabrics produced from the polymers. Too much titanium dioxide present within the polymer however, can have an adverse effect on the softness of the fabrics produced from the polymer.

As described above, it has been found that by adding a mixture of at least one mineral filler and titanium dioxide to the polymeric materials, the fibers and fabrics made from the polymer have been shown to be softer and less rigid than the fibers and made fabrics of the polymer only. Although it is unknown, it is believed that the filler mixture incorporated in the polymer actually changes the physical properties of the polymer. In particular, it is believed that the fillers modify the modulus of the fiber and the fabric creating the increased cloth-type properties.

In addition to producing more cloth-like fabrics of the polymeric materials, the mixture of fillers added to the polymers according to the present invention has also improved the ability of the polymers to be extruded and pulled out of fibers. For example, it has been found that the polymers containing the fillers can withstand higher jalad forces. Thus far, the fibers bonded with spinning have been produced having a dernier of about 1 to about 3 dpf. It is believed, however, that fibers having a dermal of minus 1 can also be produced.

In addition to adding mineral fillers and titanium dioxide to a polymeric material according to the present invention, in some applications, it may also be desirable to add optical brighteners to the polymer. For example, some mineral fillers, especially clays, when added to a polymer can give the polymer a clay cone crudc. In some? Incorporations, this color may be preferred. In other applications, however, it may be desirable to add the optical brighteners to the polymer which can make the polymer appear whiter.

The thermoplastic polymer mixed with the mixture of fillers according to the present invention may vary and will generally depend on the particular application. For most applications, a polyolefin polymer, such as controlled rheology polypropylene, polyethylene and copolymers thereof is used. Other thermoplastic polymers, however, which are very suitable for use in the process of the present invention include polyamides such as nylon, polyesters, blends of the above-mentioned polymers and copolymers of the aforementioned polymers.

In one embodiment, the thermoplastic polymer comprises a mixture of polymers, such as controlled rheology polypropylene mixed with a polyamide or a reactor class polypropylene. For example, in one embodiment, the polypropylene is mixed with from about 2 percent to about 5 percent percent of a polyamide. The polymer combination given above is also believed to improve the strength of the fibers and further improve the cloth-like qualities of the resulting fabrics. The mixing of the polypropylene with a polyamide to produce soft and strong fabrics is described in the patent application to the United States of America No. 08 / 769,820 filed by the assignee of the present invention, and which is incorporated herein by reference. by reference.

Commercially available polymers that can be used include polypropylene PF 305, which is marketed by Montel USA, Inc. of Wilmington, Delaware; E5D47 polypropylene, which is marketed by Union Carbide; and 6D43, polypropylene-polyethylene copolymer which is also marketed by Union Carbide. Polypropylene PF305 and polypropylene E5D47 both have a melt flow rating of about 38 grams per 10 minutes. The 6D43 copolymer, which contains ethylene in an amount of about 3.2 percent, on the other hand, has a melt flow rating of about 35 grams per 10 minutes when measured at 230 ° C according to the ASTM D1238 condition test.

The filler polymer combination of the present invention can be used to form discontinuous fibers and continuous fibers, which include filaments linked with spinning. In addition, the fibers can be single component fibers or multi component fibers, such as bicomponent fibers.

In general, the filler mixture is combined with the thermoplastic polymer before or during the formation of the fibers. In one embodiment, the fillers are blended with the thermoplastic polymer before extruding the polymer into fibers. In some applications, a vehicle such as a wax can be mixed with the filler before combining the filler with the polymer.

For example, the wax that can be used in the present invention includes low molecular weight and low density polymers, such as polyethylene or polypropylene. In one embodiment, the vehicle can be mixed cor. the fillers in a proportion with weight of about 1 to 1 before viewing the thermoplastic polymer. It is a particular advantage that some waxes, such as low density polyethylene, have also discovered to improve in some way the smoothness of the resulting polymer.

In addition to using a wax, the fillers can also be used which are coated with an organic material. For example, the filling particles can be coated with stearic acid, which provides a better dispersion of the filler in the polymer melt and facilitates the production of the fibers.

When the invention is mixed with the polymer, the polymer can be formed into fibers according to, for example, a spinning process or a melt blowing process. For example, in a spinning process, the polymer and the filler mixture can be melted and spun into fibers by pumping the polymer mixture through a multitude of capillary cups arranged in a uniform array of columns and rows. Even though the extrusion rate and temperature can vary dramatically depending on the application, for most applications the polymer mixture will be spun at a rate of from about 0.4 gram per minute to about 2.5 grams per minute, and at a temperature of from around 180 ° C to around 235 ° C.

After extrusion the fibers are held by high speed air. The air creates a pull force on the fibers that pull these down to a desired denier. After attenuation, the pulled fibers are directed to a perforated surface, such as a moving grid or a forming wire. The fibers are randomly deposited on a perforated surface to form a sheet. The sheet can be maintained on the perforated surface by a vacuum force.

Once formed, the fiber sheet can then be joined as desired. In one case, examples of the different methods for joining the sheet include thermal bonding, ultrasonic bonding, hydroentanglement and air binding.

Thermal bonding is very common and involves passing a fabric or cloth of fibers that are to be joined through a heated calender roll and an anvil roll. The calendering roll is usually patterned in some manner so that the entire fabric is not bonded through its entire surface. Various patterns can be used in the process of the present invention without affecting the mechanical properties of the fabric. For example, the fabric can be joined according to a knitted pattern with ribs, a wire weave pattern, a diamond pattern and the like.

After being joined, the resulting fabric can be subsequently treated if desired. For example, the fabric may undergo an orientation process in the machine direction, a creping process, a hydroentanglement process or an etching process. It has been found that the combination of fillers added to the fabric according to the present invention further improves the appearance of a fabric after any of the aforementioned post-treatment processes, especially in relation to tissues containing only titanium dioxide. In particular, after the subsequent treatment, it has been discovered that the tecs look more like cloth than conventional fabrics.In addition to the spin-linked fabrics, the polymer blend of the present invention can also be used to produce meltblown fabrics. The meltblown fabrics can be produced by extruding the polymer mixture through a die to form the fabrics. fibers. As the molten polymer exits the matrix, a high pressure fluid, such as heated air or steam, can be used to attenuate the molten polymer fibers. The surrounding cold air can then be induced inside the hot air stream to cool and solidify the fibers. The fibers are then deposited randomly on a perforated surface to form a fabric. Since the fibers can be partially fused when they are deposited on the perforated surface, the initial fabric has integrity. If desired, however, the fabric may be further bonded, in a manner similar to the bonding process described above in relation to the formation of the spin-linked fabrics.

The present invention can be further understood with reference to the following examples.

During each of the following examples, the routine test methodology was used to test the properties of interest for each of the tissue samples produced. n final description of each test is given: Base Weight: The basis weight is the mass of material.l per unit area and is measured according to the test number ASTM D3776-96 option C. The basis weight is measured in ounces per square yard.

Resistance: The grip tension test is a measure of the resistance to breaking and elongation or stress of a fabric when subjected to a unidirectional tension. This test is known in the art and conforms to the specifications of method 5,100 of the Federal Standard Test Methods 191A. The results are expressed in pounds or grams at breaking and the percent stretch before breaking. The upper numbers indicate a more stretchable and stronger fabric. The term "load" means the force or maximum load, expressed in units of weight, required to break or tear the sample in a stress test. The term "effort" or "total energy" means the total energy under an elongation curve. against load as expressed in the weight-length units. The term "elongation" means the increase in length of a sample during a stress test. The grip tension test uses 2 fasteners, each having two jaws with each jaw having one face in contact with the sample. The fasteners keep the material in the same plane, usually vertical, separated by 3 inches X6 -11) ers and are separated at a specified extension rate. The values for grip strength and grip elongation are obtained using a sample size of 4 inches (102 millimeters) by 6 inches (152 millimeters) with a jaw face size of 1 inch (25 millimeters) per one inch and a constant extension rate of 300 millimeters / minute. The sample is wider than the grip jaws to give results representative of the effective strength of the fibers in the clamped width or combined with the additional strength contributed by the adjacent fibers in the fabric. The sample is held, as for example, in a Sintech 2 tester available from Sintech Corporation, of Cary, North Carolina, an Instron ™ model, available from Instron Corporation, of Canton, Massachusetts, or an available Thwing-Albert INTELLECT II model. of Thwing-Albert Instrument Company, of Philadelphia, Pennsylvania. This simulates very closely the fabric stress conditions in actual use. The results are reported as an average of 3 samples and can be carried out with the sample in the transverse direction (CD) or in the machine direction (MD).

"Trap" Tear Test. The "trap" or Trapezoid tear test is a tension test applicable to both woven and non-woven fabrics. The full width of the sample is caught between the fasteners, therefore the primary test measures the bond or the interlock and the strength of the individual fibers directly in the tension arya, rather than the strength of the composite structure of the fabric as a whole. The procedure is useful in estimating the relative ease of tearing the fabric. It is particularly useful in determining any appreciable difference in strength between the machine direction and the transverse direction of the fabric.

In performing the trap tear test, an outline of a trapezoid is drawn on a sample of 3 by 6 inches (75 by 152 millimeters) with the largest dimension in the direction being tested, and the sample is cut off in the form of the trapezoid. The trapezoid has a side of 4 inches (102 millimeters) and a side of 1 inch (25 millimeters) which are parallel and which are separated by 3 inches (76 millimeters). A small preliminary cut of 5/8 of an inch (15 millimeters) is made in the middle of the shortest of the parallel sides. Samples are seized, for example, in an Instron Model TM apparatus available from Instron Corporation of Canton, Massachusetts or in a Thwing-Albert apparatus given IX7? LL? CT II available from the Thwing-Albert Instrument Company of Philadelphia Pennsylvania which has Parallel fasteners 3 inches long (76 mm) the sample is clamped along the non-parallel sides of the trapezoid so that the fabric on the longer side is loose and the cloth? The iron on the side will hold that tight, and with the cut in half between the fasteners. A continuous load is applied to the sample so that the cut propagates through the width of the sample. It should be noted that the longest direction is the direction being tested even when the tear is perpendicular to the length of the sample. The force required to completely tear the sample is recorded in pounds with the higher numbers indicating greater resistance to tearing. The test method used conforms to the ASTM D-1117 -14 standard test except that the tear load is calculated as the average of the first highest and highest recorded rather than the lowest and highest maximums. Five samples of each sample must be tested.

Softness: The softness of a non-woven fabric can be measured according to the "cup crush" test. The cup test evaluates the stiffness of the fabric by measuring the peak load required for a hemispherically shaped foot of 4.5 centimeters in diameter to crush a piece of cloth 23 centimeters by 23 centimeters shaped into an inverted cup of 6.5 centimeters in diameter by 6.5 centimeters in height while a cup-shaped cloth is surrounded by a cylinder of approximately 6.5 centimeters in diameter to maintain a uniform deformation of the cup-shaped fabric. An average of 10 readings is used. The foot and cup are aligned to avoid contact between the walls of the cup and the foot which could affect the readings. The peak load is m.edica while 6: 1 foot is being lowered at a rate of about 0.25 inches per second (38 centimeters per minute) and is measured in grams. A lower cup crush value indicates a softer laminate. The cup crush test also gives a value for the total energy required to crush a sample ("cup crush energy") which is the energy from the start of the test to the maximum load point, for example the area under the curve formed by the load in grams on one axis and the distance that the foot travels in millimeters on the other. Cup crush energy is reported in grams-millimeter. A suitable device for measuring cup crushing is a model FTD-G500 load cell (500 gm range) available from Schaevitz Company, of Pennsauken, New Jersey.

The drop test was also used to determine the stiffness of the material. The drop stiffness test as also sometimes called the cantilever bending test, determines the length of bending of a fabric using the principle of the folded overhang of the fabric under its own weight. The length of bending is a measure of the interaction between the weight of the fabric and the rigidity of the fabric. A 1 inch (2,? 4 centimeters) by 8 inches (20.3 centimeters) strip of fabric is slid to 4.75 inches per minute (12 centimeters per minute) in directions parallel to its long direction so that the Front edge is projected from the edge of a superieicie oriccr.t = 1. the. lonrit ~ - dQ le? a? .c superior is measured when 1 = tip of the sample is pressed under its own weight to the pumo er. where the line joining the tip of the fabric to the edge of the platform makes an angle of 41.5 ° with the horizontal. The longer the hanging, the slower the sample will bend, indicate a stiffer fabric, the rigidity of the fall is calculated as 0.5 per bending length. A total of each cloth must be taken. This procedure conforms to the ASTM D-138 standard test? except for the length of the fabric which is different (longer) and a Federal Method 5306 of the Test Method Standard number 191 A. The test equipment used is a cantilever bend tester model 79-10 available from Testing Machines, Inc., 400 Bayview Avenue, Amitville, Neva York 11,701. As in most tests, the sample should not be conditioned to ASTM 65 + 2 in relative humidity and 72 + 2 ° F (22 + 1 ° C) or TAPPI conditions of 50 + 2 percent relative humidity and 72 +1, 8 ° F before the test.

The Handle-O-Meter: The softness of a non-woven fabric can be measured according to the "handle-o-meter" test. The test used here is the first INDA standard test 90.0-75 (R 82) with two modifications: 1. The sample size was 4 inches by 4 inches and; 2. Five samples were tested rather than two. The test was carried out on a model Handle-O-Meter model 211-5 of Thwing-Albert Instrument Co. , Philadelphia, Pennsylvania.

Abrasion: Apart from the Taber abrasion test, it indicates the durability of the fabric against abrasion. The test used here conforms to the 5306 method, the Standard Test Methods Standard number 191 A and the standard test. ASTM number S1175 (using a double wheel). The fabric is subjected to a repetitive rotating rubbing action under controlled pressure and abrasive action. After a specified number of cycles, the eroded fabric is visually graded against a set of control photographs by means of a system in which 1 means severe abrasion and 5 means the least abrasion.

In the Martendales test, the sample is worn out while the direction of the abrasive is continuously changed. This test measures the relative resistance of a fabric to abrasion. The test results are reported on: a scale of 1 to 5 with 5 being the least wear and 1 being the highest, after 120 cycles with a weight of 1.3 pounds per square inch, the test is carried out with an abrasion and tear tester Martindale such as model number 103 or model number 403 available from James H. Heal Company, Ltd of Yorkshire, England. The abrasive used is a 36 inch by 4 inch by 0.05 thick silicon rubber wheel reinforced with fiberglass having a rubber surface hardness of 81A Durometers, Shore A of 81 plus or minus 9. The abrasive is available from Elirth Insulaticn Inc .. a distributor for Connecticut Hard Rubber, 925 Industrial Park, NE, Marietta, Georgia 30,065.

The reciprocation abrasion test is used to evaluate the abrasion and integrity of the surface bonding of the material. The poorly bonded material will exhibit a surface and villus stringing. The test material is compared to standard photographs and is rated with either 1,3 or 5, with 1 meaning the most hairy to spinning.

Absorption: The oil or water absorption capacity test is used to determine the capacity of; A cloth to absorb either water or mineral oil, but it is applicable to other liquids as well. The test as used here conforms to the ASTM test number D 1117.5.3-80. The absorption is determined as the weight of the liquid absorbed by the sample and as a percentage of the sample unit weight. Higher results indicate a higher absorption capacity of the sample.

Color: The Hunter color test measures the color values of a given fabric using a colorimeter with the illumination provided by a CIÉ Standard source and reports observed data under numbered or simulated sky daylight conditions.

The whiteness as used here is measured according to the ASTM E3.313333-73 D 1925-70 methods on a Hunter D25A9 color meter model with a CIÉ 2 source of illumination, the brightness as used here is measured in accordance with ASTM 523 standard on a Hunterlab modular brightness meter D48-7 using brightness values of 60 °.

EXAMPLE NO. 1 The tests described above were carried out in order to demonstrate the strength, softness and durability of the fibrous tissues made according to the present invention.

Eight (8) different woven products were produced and tested. The tested fabrics were made c.e a random copolymer comprising 97 percent polypropylene and 3 percent polyethylene. The samples were as follows: TABLE 1 SAMPLE SAMPLE NUMBER Random copolymer 1 Random copolymer and 2% Ti02 2 Waxy Copoiimer 5% Wax 3 Random copolymer, 5% wax, 4 and 2% Ti02 Random copolymer, 5% wax and 5 5% CaCO3 (Calcite) Random copolymer, 5% wax, 6 5% CaCO3 (Calcite), and 2% Ti02 Random copolymer, 5% wax and 7 5% CaCO3 (Aragonite) Random copolymer, 5% wax and 8 5% CaC03 (Aragonite) and 2% Ti02 The random copolymer used was 6D43 polymer obtained from Union Carbide. In the table given above, the wax refers to a linear low density polyethylene marketed as AC16 by Allied Signal of Morristown, Neva Jersey. Calcium carbonate having the structure of calcite used in the samples was obtained from Specialty ALBAGLOSS filler Mineral, Inc. while calcium carbonate having ia ARAGONITE structure used in the samples was obtained MAGNUMGLOSS filler Mississippi Lime Company. The titanium dioxide was incorporated into the samples in a 50 percent concentrate of titanium dioxide in controlled rheology polypropylene of melt flow rate 35.

The samples mentioned above were made into fibers through a spinning process and formed into non-woven fabrics. The spinning conditions and the binding apparatus were not optimized but were constant for all the samples. The base weight of each sample is about one ounce per square yard. Once the tissue was formed, a bound pattern was etched onto the tiles using the bonding rollers. The denier of the fibers produced ranged from about 2.0 to about 2.5. The various tests were carried out on each of the samples. The following results were obtained: TABLE 2 15 From the data given above, a number of generalities were observed. For example, the addition of titanium dioxide to the polymer tended to make the fabric stronger and more rigid. The addition of wax, however, tended to nullify the negative effect of titanium dioxide on softness. The wax, however, tended to reduce the strength of the fabric when it was added in larger quantities.

The addition of calcium carbonate that it has; a calcite structure decreased the peak tear charge of the trap but increased the peak load of increased grip stress, suggesting that the strength of the fiber was decreased while the strength of the composite fabric was increased. The calcium carbonate having the aragonite structure, on the other hand, tended to increase both the peak charge of tearing trap and the maximum load of grip tension; The addition of calcium carbonate to the polymer also tended to increase smoothness.

EXAMPLE No. 2 Spunbonded fabrics were made according to the procedure described in Example 1. In this example, however, instead of using a random copolymer, the fabrics were made of polypropylene.

Six (6) different tissue products were produced and tested. The samples are as follows.

TABLE 3 SAMPLE SAMPLE No, Polypropylene 1 Polypropylene and 2% Ti02 2 Polypropylene and 4% Ti02 3 Polypropylene, 5% wax, 5% kaolin and 2% 4 Ti02 Polypropylene, 5% wax and 5% kaolin 5 (0.6 ghm) and 2% Ti02 Polypropylene, 5% wax, 5% CaCO3 6 (Aragonite), and 2% Ti02 The polypropylene used above was PF305 obtained from Montell USA, Inc. and which had a flu rating; or melt of 38 grams per 10 minutes. The kaolin listed above was obtained from ECC, Inc. When the spunbond fibers were used, the polymer was extruded at a rate of 0.7 GHM except that sample 5 which was extruded at a rate of 0.6 ghm. .

The same conventional methods used for the test procedures in Example 1 were used to test these polypropylene products.

The following results were obtained.

TABLE 4 As shown above, the addition of titanium dioxide to polypropylene seems to decrease the softness. The addition of calcium carbonate or kaolin, however, reversed the effects of titanium dioxide and increased softness. During testing, it was also visually noted that the addition of titanium dioxide gave the resulting fabrics a more cloth-like appearance.

EXAMPLE No. 3 The non-woven fabrics bonded with spinning were made according to the procedures described in Example 1 of the polypropylene polymer identified in Example 2. In this example, the binding temperature of the cloth products was varied in order to optimize the results . Three (3) different woven products were produced and subsequently tested at several different bonding temperatures. The samples and a list of your conferencing cc's are listed below.

TABLE 5 The samples were tested as described above and the following results were obtained. fifteen As shown above, in general, the softness increased at the lower bonding temperatures, while the strength increased at higher bonding temperatures. In this example, as shown above, the softness dramatically increased dramatically when a mineral filler was added to the polypropylene. EXAMPLE No.4 The following experiments were carried out 10 in order to demonstrate the effects of the addition of the wax to the tissue products. Five (5) different woven products were produced from the yarn-linked polypropylene fibers similar to the processes described in examples 1 and 2. The samples and a list of their components are listed below. They last temperature d results.

Sample Sample No.

Polypropylene, 2.5% kaolin, and 2% Ti02 3 TABLE 8 15 As shown above, the inclusion of the polyethylene wax in the mixture increased the softness of the fabric but also decreased the strength. The sample does not 3 made in accordance with the present invention also showed an increase in softness, the tensile strength of example no. 3, however, is higher compared to examples Nos. 1 and 2 EXAMPLE No. 5 The following example was carried out in order to show the effects of TiO-, and of the clay on the brightness and the whiteness of the spin-canned fabrics made in a manner similar to the procedures described in examples 1 and 2 given above.

The brightness is defined as the reflected light that is spectacularly bright. _.sto tamoier p_.eoe _yar brightness or surface luster. Brillo is a geometric attribute of appearance, which is associated with the distribution of light from the object. The test was done using the Hunterlab D48-7 modular brightness meter. The superior results of the brightness meter indicate a greater amount of light reflected from the material.

The whiteness and yellowness indexes were determined for the fabrics by using the Hunterlab Tristimulus D25A-9 colorimeter. The whiteness is based on a bluish white, the preferred white and is reduced by signs of yellow and gray. Yellowing is caused by absorption in the blue part of the spectrum.

The two components of Ti02 and the mineral replenisher such as clay work together to reduce the brightness. This combination of Ti02 and mineral fillers is essential for an aesthetic gain over conventional polypropylene fabrics as well as for improved smoothness. This is because the Ti02 significantly lowers the brightness by itself while the mineral combination found in the clay also lowers the brightness and greatly improves the softness of the material.

A sample of a well-bonded polypropylene TV was tested for brightness and whiteness before and after the addition of Ti02 and kaolin.

The following results were obtained: TABLE 9 WHITE BRIGHTNESS SHOWS Polypropylene 11 Polypropylene and 2% Ti02 3.5 ¡5 Polypropylene, 2% Ti02, 2.5% 2.9 11 kaolin Polypropylene, 2% Ti02, 5% kaolin 2.5 79 The effect of lowering the brightness of polypropylene fabrics can also be seen in another set of data collected for data produced at different bonding temperatures. Three (3) woven products linked with different yarns were produced and tested. The samples, their components, and their corresponding sample numbers are listed in Table 10 given below. TABLE 10 SAMPLE SAMPLE No Polypropylene and 2% Ti02 1 Polypropylene, 2% Ti02, 2.5% kaolin 2 Polypropylene, 2% Ti02, 5% kaolin 3 These fabrics were tested for brightness and the following results were obtained. TABLE 11 As shown above, the addition of titanium dioxide dramatically reduces the brightness of polypropylene. The addition of a mineral filler, however, also decreased the gloss of the fabrics. Low gloss fabrics have a more cloth-like appearance.

During the trial, it was observed that when larger quantities of clay were added to the tissues, the ones tended to exhibit more than one dye or tone of clay-raw. In some applications, this color is desirable. If a fabric that appears whiter is preferred, however, the optical brighteners can be added or the clay can be replaced with calcium carbonate.

EXAMPLE No. 6 The non-woven fabrics bonded with spinning are made according to the procedures described in Example 1 with a polypropylene polymer. In this example, the effects of the subsequent treatment of a fabric by orienting the fibers contained within a tissue attached in the machine direction were studied. The samples and a list of their components are listed below.

TABLE 12 SAMPLE SAMPLE No.

Polypropylene and 2% Ti02 1 Polypropylene, 2.5% kaolin and 2% Ti02 2 Polypropylene, 5% kaolin and 2% Ti02 3 Each of the samples mentioned above were subjected to a machine direction orientation (MDO) treatment sometimes referred to as "narrowing" or "narrowing and stretching". In particular, the samples were drawn in the direction of the machine using rollers. Stretching caused the fibers contained within the fabrics to be oriented in the direction of the machine. This mechanical treatment of the tissues is more particularly described in the patent application to the United States of America number 08 / 639,637 owned by the assignee of the present invention, and which is incorporated herein by reference.

Each of the samples listed above were measured for softness. In particular, for each sample, a fabric was tested that had been subjected to the orientation in the machine direction described above and a fabric was tested that had not undergone such treatment. The following results were obtained: TABLE 13 SAMPLE No. CRUSH LOADING ENERGY OF CUP (s) CUP CRUSHING (g / mm) 1 91 1852 2 80 1332 3 67 1207 1 + MDO 66 1135 2 + MDO 51 815 3 + MDO 40 693 As shown, the orientation treatment in the machine direction also increases the softness of the fabrics.

EXAMPLE No. 7 The non-woven fabrics bonded with spinning were made according to the procedures described in Example No. 1 of the polypropylene polymer identified in Example No. 2. In this example, the characteristics of the fabrics of long-term heat aging they were made in accordance with the present invention and were studied. Three (3) different fabric products were produced and tested. The samples and the list of their components are as follows: TABLE 14 SAMPLE SAMPLE No.

Polypropylene and 2% Ti02 1 Polypropylene, 5% polyethylene wax, 2% 2 Ti02 and 5% kaolin Polypropylene, 5% polyethylene wax, 2% 3 of Ti02 and 5% of aragonite (calcium carbonate) The fabrics mentioned above were cut into samples having dimensions of approximately three inches by 6 inches. At least 3 specimens of each sample were tested. The stability of thermal aging was tested by placing each sample in a forced air oven set at a temperature of 140 ° C. The samples were placed flat on a PYREX dish and tested periodically until the failure occurred. The point of failure for the test was when the fabric became brittle so that the fabric disintegrated with a small force exerted on said fabric in the direction transverse to the machine.

The following results were obtained TABLE 15 As shown above, the filler formula of the present invention greatly improved the thermal aging stability of the fabrics compared to a tissue containing only titanium dioxide.

These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, with the spirit and scope of the present invention, which is more particularly set forth in the appended claims. It should further be understood that the aspects of the various embodiments may be exchanged in w or in part. In addition, those of ordinary skill in the art will appreciate that the foregoing description is only by way of example only, and that no attempt is made to limit the invention thus further described in such appended claims.

Claims (44)

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

1. A process for producing a non-woven fabric other than a polymeric fiber cloth type, said process comprises the steps of: incorporating a mixture of fillers into the thermoplastic polymer material, said filler blends comprise titanium dioxide and a mineral filler; forming said thermoplastic polymeric material into fibers; Y creating a non-woven fabric of said fibers wherein said mixture of fillers is incorporated in the polymeric material in an amount sufficient to decrease the stiffness and increase the softness of the non-woven fabric as compared to a non-woven fabric made of said thermoplastic polyimic material which it does not contain these fibers.

2. A process, as claimed in clause 1, characterized in that said mineral filler comprises the material selected from the group consisting of kaolin clay, calcium carbonate, talc, attapulgite clay, and mixtures thereof.

3. A process, as claimed in clause 1, characterized in that said mineral filler comprises the material selected from the group consisting of calcium carbonate, kaolin and mixtures thereof.

4. A process, as claimed in clause 1, characterized in that said mixture of fillers is added to said thermoplastic polymer material in an insufficient quantity so that said fillers protrude essentially from the surface of said forming fibers.

5. A process, as claimed in clause 1, characterized in that said titanium dioxide is added to said thermoplastic polymer material in an amount of from about 0.5 to about 4% by weight wherein said mineral filler is added to said thermoplastic polymer material in an amount of from about 3.1% at around 1C% per weight.

6. A process, as claimed in clause 1, characterized in that said titanium dioxide is added to said thermoplastic polymer material in an amount of from about 1% to about 2% by weight and wherein said mineral filler is added to said thermoplastic polymer material in an amount of from about 2.5% to about 5% by weight.

7. A process, as claimed in clause 1, characterized in that said mineral filler comprises a clay.

8. A process, as claimed in clause 1, characterized in that the thermoplastic polymer material comprises polypropylene and a copolymer comprising propylene units.

9. A process, as claimed in clause 1, characterized in that said fibers are formade.s according to a process of linking with spinning or according to a process of blowing with fusion.

10. A process, as claimed in clause 1, characterized in that said thermoplastic polymeric material comprises a mixture of polypropylene and a polyamide.

11. A process, as claimed in clause 1, characterized in that said mixture also comprises a wax.

12. A fiber adapted to produce fabrics having cloth-like characteristics comprising a thermoplastic polymer containing a mixture of fillers, said mixture of fillers comprises titanium dioxide and a mineral filler, said fillers are encapsulated within the thermoplastic polymer so that said Fillers do not protrude essentially from the surface of said fiber.

13. A fiber, as claimed in clause 12, characterized in that said titanium dioxide is present within the thermoplastic polymer in an amount of less than about 4% by weight and wherein said mineral filler is present within the thermoplastic polymer in an amount of less than about 10% by weight.

14. A fiber, as claimed in clause 12, characterized in that said titanium dioxide is present within the thermoplastic polymer in an amount of from about 1% to about 2% by weight and wherein said mineral filler is present within the thermoplastic polymer in an amount of from about 2.5% to about 5% by weight.

15. A fiber, as claimed in clause 12, characterized in that said thermoplastic polymer comprises polypropylene or a copolymer comprising propylene units.

16. A fiber, as claimed in clause 15, characterized in that said titanium dioxide is present within the thermoplastic polymer in an amount of from about 1% to about 2% by weight and where mineral filler is present within of the thermoplastic polymer in an amount of from about 2.5% to about 5% by weight.

17. A fiber, as claimed in clause 12, characterized in that said mineral filler comprises a material selected from the group consisting of kaolin, calcium carbonate and mixtures thereof.

18. A fiber, as claimed in clause 12, characterized in that it also comprises a vehicle for facilitating the addition of said fillers to said thermoplastic polymer, said vehicle comprises a wax.

19. A fiber, as claimed in clause 12, characterized in that said fiber comprises a fission blown fiber or a fiber bonded with yarn.

20. A fiber, as claimed in clause 12, characterized in that said thermoplastic polymer comprises a mixture of polypropylene and a polyamide, polyamide is present in said thermoplastic polymer in an amount of up to about 5% by weight.

A fiber, as claimed in clause 12, characterized in that said mixture also comprises a wax.

22. A non-woven fabric comprising fibers made of a thermoplastic polymer, said thermoplastic polymer contains a mixture of fillers, said mixture of fillers comprises titanium dioxide and a mineral filler, said fillers are encapsulated within said thermoplastic polymer so that said fibers do not they protrude essentially from the surface of said fibers.

23. A non-woven fabric, as claimed in clause 22, characterized in that said material filler comprises a material selected from the group consisting of kaolin, calcium carbonate and mixtures thereof.

24. A non-woven fabric, as claimed in clause 22, characterized in that said titanium dioxide is present within said thermoplastic polymer in an amount of up to about 4% by weight, and in sode said mineral filler is present within said thermoplastic polymer in an amount of up to about 10% by weight.

25. A non-woven fabric, as claimed in clause 22, characterized in that said thermoplastic polymer comprises polypropylene or a copolymer comprising propylene units.

26. A non-woven fabric, as claimed in clause 22, characterized in that said fibers comprise meltblown fibers or fibers bonded with yarn.

27. A non-woven fabric, as claimed in clause 22, characterized in that said thermoplastic polymer comprises a mixture of polypropylene and a polyamide, said polyamide is present in said thermoplastic polymer in an amount of up to about 5% by weight .

28. A non-woven fabric, as claimed in clause 22, characterized in that said mixture further comprises a wax.

29. A nonwoven fabric of the cloth type comprising fibers made of an extruded polymer, said polymer comprises a thermoplastic polymer containing a mixture of fillers, said mixture of fillers comprises titanium dioxide present in an amount of up to about 4% by weight and a mineral filler present in an amount of up to about 10% by weight, said fillers are encapsulated within said thermoplastic polymer.

30. A non-woven fabric, as claimed in clause 29, characterized in that said thermoplastic polymer comprises polypropylene or a copolymer comprising propylene units.

31. A non-woven fabric, as claimed in clause 29, characterized in that said titanium dioxide is present within said thermoplastic polymer in an amount of from about 1% to about 2% by weight, and wherein said filler The mineral is present within said thermoplastic polymer in an amount of from about 2.5% to about 5% by weight.

32. A non-woven fabric, as claimed in clause 31, characterized by said rene lene mineral comprises kaolin.

33. A non-woven fabric, as claimed in clause 31, characterized in that said mineral filler comprises calcium carbonate.

34. A non-woven fabric, as claimed in clause 29, characterized in that said expanded fibers comprise meltblown fibers or fibers bonded with yarn.

35. A non-woven fabric, as claimed in clause 29, characterized in that said thermoplastic polymer comprises a mixture of polypropylene and a polyamide, said polyamide is present in said thermoplastic polymer in an amount of up to about 5% by weight.

36. A non-woven fabric, as claimed in clause 29, characterized in that said mixture further comprises a wax.

37. A cloth-type non-woven fabric comprising fibers made from an extruded polymer, said polymer comprises a mixture of polypropylene and a polyamide, said polymer contains a mixture of fillers, said mix of fillers comprises titanium dioxide present in an amount up to about 4% by weight and a mineral filler present in an amount of up to about 10% by weight, said fillers are encapsulated within said polymer.

38. A non-woven fabric, as claimed in clause 37, characterized in that said polymer comprises up to about 5% by weight of said polyamide.

39. A non-woven fabric, as claimed in clause 37, characterized in that said mineral filler comprises kaolin.

40. A non-woven fabric, as claimed in clause 37, characterized in that said mineral filler comprises calcium carbonate.

41. A non-woven fabric, as claimed in clause 37, characterized in that said mixture also contains a wax.

42. A process for improving the stability of thermal aging of a non-woven fabric made of polymeric fibers, said process comprises the steps of: incorporating into the thermoplastic polymeric material a mixture of fillers, said material of reller.ac.cres comprising titanium dioxide and a mineral filler; forming said thermoplastic polymeric material in the fibers; Y creating a non-woven fabric of said fibers, wherein said mixture of fillers is incorporated in said polymeric material in an amount sufficient to increase the stability of thermal aging of said non-woven fabric.

43. A process, as claimed in clause 42, characterized in that said thermoplastic polymer material comprises polypropylene.

44. A process, as claimed in clause 42, characterized in that said mineral filler comprises a material selected from the group consisting of kaolin, clay, calcium carbonate and mixtures thereof, said mineral filler being present in dichc polymeric material in an amount of up to about 10% by weight, and wherein said titanium dioxide is present in said polymeric material in an amount up to about 4% by weight. SUMMARY Extruded fibers and non-woven fabrics made of the fibers are described having improved cloth-like properties and an improved aesthetic appearance. The fibers used to form the fabrics are made of a thermoplastic polymer containing titanium dioxide and at least one mineral filler such as a calcium carbonate or caloin. In particular, the fillers are aggregated in an amount so that the fillers are encapsulated within the polymeric material.