MXPA97004801A - Photo-stabilization package used in non-woven fabrics and non-woven fabrics containing the mi - Google Patents

Abstract

The present invention relates to a package of stabilizer additive for non-woven fabrics. The package has a pigment based on bismuth vandata and a hindered amine light stabilizer. Bismuth vandate is added to a non-woven fiber polymer before extrusion in an amount of between about 0.1 and 3 percent by weight based on the weight of the fabric and the amine locked in an amount of between about 0.25. and 2.5 percent by weight based on the weight of the fabric. The non-woven fabric also provided by this invention can be used as protective covers for, for example, boats, and wagons, and as a weathering cloth, for example, for tents and pavilions

Description

PHOTOSTABILIZATION PACKAGE USED IN NON-WOVEN FABRICS AND THE NON-WOVEN FABRICS CONTAINING THE SAME.

BACKGROUND OF THE INVENTION Non-woven fabrics are used for a wide variety of applications from baby cleaners and diapers to automotive covers and geotextiles. These applications require materials having diverse attribute properties. Some applications, for example, require nonwovens which are highly humidifying, for example, allowing liquids to pass quickly through them, for example, diapers and women's hygiene products and which are generally intended for a short use and for availability. Others require a high degree of repellency and photostability, for example outdoor fabrics such as car covers, awnings and pavilions for a longer term use.

Since most nonwovens are made of polymers containing chromophores, they tend to react relatively when exposed to prolonged periods of time to energy sources such as sunlight. This reactivity and the subsequent oxidation of the fabric results in a serious deterioration of the tensile strength of the fabric. Therefore, one of the most difficult problems facing designers of non-woven fabrics with respect to outdoor use has been to improve the retention of tensile strength with exposure to sunlight, for example, the photostability of the fabric .

A combined difficulty has been that it is usually desirable to color or pigment the non-woven fabrics to be used on the outside since the color of the original polymer tends to be quite dull, and it has been found that most of the pigments currently known have a negative effect on the photostability of non-woven fabrics. To complicate matters, many pigments contain dyes or other ingredients, which are toxic and therefore not allowed. As a result of this, there is a small class of pigments that can be used in a non-woven fabric and these have a negative effect on the life of the fabric due to the deterioration of the tensile strength that can be caused.

It is an object of this invention to provide a stabilization additive package for non-woven fabrics which includes a pigment and which greatly improves the retention of the tensile properties of the non-woven fabric with exposure to sunlight.

It is another object of this invention to provide a nonwoven fabric having an additive stabilization package.

SYNTHESIS The objects of the invention are provided by an additive package containing hindered amine light stabilizers or HALs and a pigment based on bismuth vandate. The HAL may be present in an amount of between about 0.25 and 2.5% by weight and the pigment based on bismuth vandat may be in an amount between about 0.1 and 3% by weight of the non-woven fabric.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plot of one percent retention of tensile strength (y-axis) against months of exposure to sunlight in South Florida (x-axis) for fabrics made with additives as described in the examples 1, 2 and 3. The data for this Figure will be in Table 1.

Figure 2 is a graph of percentage of tensile strength retention (y axis) against months of exposure to sunlight in South Florida (x axis) for fabrics made with additives as described in examples 4 to 9. The data for this Figure are given in Table 1.

DEFINITIONS As used herein, the term "fabric or nonwoven fabric" means a fabric having a structure of individual fibers or yarns, which are in between but not in an identifiable manner as in a woven fabric. Non-woven fabrics or fabrics have been formed from many processes such as, for example, meltblowing processes, spinning processes and carded and bonded tissue processes. The basis weight of the non-woven fabrics is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm) and the useful fiber diameters are usually expressed in microns (note that to convert from osy to gsp, must multiply osy by 33.91).

As used herein, the term "microfibers" means fibers of small diameter having an average diameter of no more than about 75 microns, for example, having an average diameter of from about 0.5 microns to about 50 microns, more particularly, Microfibers can have an average diameter of about 2 microns around 4 microns. Another commonly used expression of fiber diameter is denier, which is identified as grams per 9000 meters of a fabric and can be calculated as a fiber diameter in square microns multiplied by the density in grams / cc, multiplied by 0.00707. A lower denier indicates a finer fiber and a higher denier indicates a heavier or thicker fiber. For example, the diameter of a given polypropylene fiber as of 15 microns can be converted to denier by squareing, multiplying result by .89 g / cc and multiplying by .00707. Therefore, a polypropylene fiber of 15 microns has a denier of about 1.42 (152 x 0.89 x 0.00707 = 1.415). Outside the United States, the unit of measurement is more commonly the "tex" which is defined as grams per square kilometers. The tex can be calculated as denier / 9.

As used herein, the term "spunbond fibers" refers to fibers of small diameter, which are formed by extruding the melted thermoplastic material as filaments of a plurality of usually circular and fine capillaries of a spinner with the filaments extruded then being rapidly reduced as by, for example, in U.S. Patent No. 4,340,563 issued to Apel et al., and in U.S. Patent No. 3,692,618 issued to Dorschner et al., Patent No. 3,802,817 issued to Matsuki et al., Patent No. 3,382,992 and 3,341,394 issued to Kinney, Patent No. 3,502,763 granted to Hartman and Patent No. 3,542,615 granted to Dobo and others. Spunbond fibers are generally non-sticky when they are deposited on the collecting surface. Spunbonded fibers are generally continuous and have average diameters (from a sample of at least 10) larger than 7 microns, more particularly, from between about 10 and 20 microns.

As used herein, the term "meltblown fibers" means fibers formed by extruding a melted thermoplastic material through a plurality of usually circular and fine matrix capillaries such as melted threads or filaments into gas streams ( for example air), usually hot, at high speed and converging, which attenuate the filaments of the melted thermoplastic material to reduce its diameter, which can be a microfiber diameter. Then, the melted blown fibers are carried by the gas stream at high speed and are deposited on a collecting surface to form a fabric of meltblown fibers disbursed at orange blossom. Such a process is described, for example, in United States Patent No. 3,849,241 issued to Butin et al. The meltblown fibers are microfibers, which may be continuous or discontinuous, are generally smaller than 10 microns in average diameter, and are generally sticky when deposited on a collecting surface.

As used herein, the term "multi-layer laminate" means a laminate wherein some of the layers are spun-bonded and some formed by meltblowing such as a spin-bonded / melt-blown / bonded laminate. yarn (SMS) and others as described in United States Patent No. 4,041,203 issued to Brock et al., in United States Patent No. 5,169,706 issued to Collier et al., in the Patent of the United States of America. United States of America No. 5,145, 727 granted to Potts et al., In United States Patent No. 5,178,931 issued to Perkins et al. And in United States Patent No. 5,188,885 issued to Timmons et al. Such lamination can be done by depositing a spunbonded web layer in sequence on a forming web first, then a layer of meltblown fabric and the last one spunbonded layer and then bonding the laminate in a manner as described above. describe below. Alternatively, the fabric layers can be made individually, collected in rolls, and combined in a separate bonding step. Such fabrics usually have a basis weight of from about 6 to 400 grams per square meter, or more particularly from about 0.75 to about 3 osy. Multilayer laminates may also have several numbers of layers formed from meltblown or multiple layers of spunbonded in many different configurations and may include other materials such as films (F) or Coform materials, eg, SMMS, SM , SFS, etc.

As used herein, the term "coform" means a process in which at least one head of meltblown matrix is arranged around a conduit through which other materials are added to the fabric as it is being formed. Such other materials can be pulp, superabsorbent particles, cellulose or short fibers, for example. The coform processes are shown in the commonly assigned Patents Nos. 4,818,464 granted to Lau and 4,100,324 granted to Anderson et al. The tissues produced from the coform process are generally considered as coform materials.

As used herein, the term "polymer" generally includes but is not limited to homopolymers, copolymers, such as block, graft, random and alternating copolymers, terpolymers, etc. and mixtures and modifications thereof. In addition, unless specifically limited otherwise, the term "polymer" will include all possible geometric configurations of the molecule. These configurations include, but are not limited to, isotactic, syndiotactic and random symmetries.

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 a direction generally perpendicular to MD.

As used herein, the term "monocomponent fiber" refers to a fiber formed from one or more extruders using only one polymer. This does not mean that fibers formed from a polymer to which small amounts of additives for coloring, antistatic properties, lubrication, hydrophilicity, etc., are added are excluded. These additives, for example, titanium dioxide for coloring, are generally present in amounts of less than 5% by weight and more typically of about 2% by weight.

As used herein, the term "conjugated fibers" refers to fibers which have been formed from at least two extruded polymers of separate extruders but spun together to form a fiber. Conjugated fibers are also sometimes referred to as multicomponent or bicomponent fibers. The polymers are usually different from one another even though the conjugated fibers may be of monocomponent fibers. The polymers are arranged in distinct zones placed essentially constantly across the cross section of the conjugate fibers and extend continuously along the length of the conjugate fibers. The configuration of such a conjugate fiber can be, for example, a pod / core arrangement where one polymer is surrounded by another or can be a side-by-side arrangement, a cake arrangement or an arrangement of "islands in the sea". . Conjugated fibers are taught in U.S. Patent No. 5,108,820 issued to Kaneko et al., In U.S. Patent No. 4,795,678 issued to Krueger et al. And in the U.S. Patent. No. 5,536,552 granted to Strack et al. Conjugated fibers are also taught in U.S. Patent No. 5,382,400 issued to Pike et al. And can be used to produce loops in the fibers by using differential rates of expansion and contraction of the two (or more) polymers. The crimped fibers can also be produced by mechanical means and by the process of the German patent DT 2513 251 Al. For the bicomponent fibers, the polymers can be present in proportions of 75/25 50/50 25/75 or any other proportions desired. The fibers may also have shapes such as those described in U.S. Patent No. 5,277,976 issued to Hogle et al. And 5,466,410 issued to Hills and 5,069,970 and 5,057,368 issued to Largman et al., Which describe fibers with unconventional shapes. .

As used herein, the term "biconstituent fibers" refers to fibers which have been formed from at least two extruded polymers 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 distinct zones relatively constantly positioned across the cross-sectional area of the fiber and the various polymers are usually non-continuous throughout the entire length of the fiber, instead of these, usually forming fibrils or protofibrils, which start and end at random.

The constituent fibers are sometimes referred to as multi-constituent fibers. Fibers of this general type are discussed, for example, in US Pat. Nos. 5,108,827 and 5,294,482 issued to Gessner. Bicomponent and biconstituent fibers are also discussed in the textbook "Polymer Blends and Compounds" by John A. Manson and Leslie H. Sperling, Copyright 1976 by Plenun Press, a division of Plenum Plublish Corporation of New York , IBSN 0-306-30831.2, page 237 to 277.

As used herein, the term "mixture" means a mixture of two or more polymers while the term "alloy" means a subclass of mixtures wherein the components are emissible but have been compatibilized. The "misibility" and the "immissibility" are defined as mixtures having negative and positive values respectively, for the free energy of mixing. "Additional co-compatibility" is defined as the process of modifying the interfacial properties of an immiscible polymer mixture in order to make an alloy.

As used herein, the term "protective cover" means a cover for vehicles such as cars, trucks, boats, airplanes, motorcycles, bicycles, golf carts, etc., covers for equipment frequently left outside such as grills, playground equipment and garden (mowers, rototillers, etc.) and meadow furniture, as well as covers for the floor, tablecloths and covers for lunch area.

As used herein, the term "outer fabric" means a fabric which is primarily, but not exclusively, used outdoors. The fabric for the exterior includes a fabric used in protective covers, a camping / towing cloth, blankets, awnings, pavilions, tents, agricultural fabrics and outer garments such as head coverings, industrial work clothes and blankets, pants, shirts, coats, gloves, socks, shoe covers and the like.

TEST METHODS Grab Tension Test: Grab tension test is a measure of the resistance to breakage and elongation or tension of a fabric when it is subjected to a unidirectional tension. This test is known in the art and conforms to the 5100 method specifications of the Federal Standard 191A test methods. The results are expressed in pounds at break and percentage of stretch before breaking. The upper numbers indicate a more stretchable and stronger fabric. The term "load" means the maximum force or load, expressed in units of weight, required to break or tear the specimen in a stress test. The term "voltage" or "total energy" means the total energy under a load against the elongation curve, as expressed in units of weight-length. The term "elongation" means the increase in length of a specimen during the stress test. The values for grip strength and grip elongation were obtained using a specific cloth width, usually 102 millimeters, a clamp width and a constant extension rate. The sample is wider than the clamp to give representative results of the effective strength of the fibers in the embraced width combined with the additional strength contributed by the adjacent fibers in the fabric. The specimen is grasped in, for example, an Instron Model TM apparatus available from Instron Corporation, 2500 Washington Street, MA Canton 02021, or a Thwing-Albert Model INTELLECT II apparatus available from the Thwing-Albert Instrument Company, 10960 Dutton Road, Phila. , PA 19154, which have parallel clamps 46 mm long. This closely simulates fabric tension conditions in actual use.

Melt Flow Rate: The melt flow rate (MFR) is a measure of the viscosity of a polymer. The MFR is expressed as the weight of material which flows from a capillary vessel of known dimensions under a specific load or cut-off rate for a measured period of time and was measured in grams / 10 minutes at a fixed temperature and load according to , for example, the ASTM 1238 90b test.

Test of South Florida: This test was carried out by exposing the fabric to the sun without a backing in Miami Florida. The samples were facing South at an angle of 45 °. Each cycle concludes with a modified stress test in pounds to measure the degradation or change in resistance to the fabric. This provides a measure of the durability of the fabric.

DETAILED DESCRIPTION OF THE INVENTION.

The field of non-woven fabrics is a diverse one encompassing absorbent products such as diapers, cleansers and products for women's hygiene and barrier products such as surgical gowns and wipes, and bandages. Non-wovens are also used for more durable applications such as protective covers and weathershields where resistance to the elements and photostability are important features.

A problem for protective covers, fabrics for outdoor and other non-woven fabrics exposed to a large amount of sunlight has been the retention of the properties of retention with time or photostability. The inventors have developed a novel stabilization additive package which can improve the photostability of the non-woven fabrics greatly. This invention also includes a nonwoven fabric having the stabilization additive package of the invention.

The fibers of which the fabric of this invention is made can be produced by the meltblown or spin bond processes well known in the art. These processes generally use an extruder to supply a melted thermoplastic polymer to a spinning organ where the polymer is fiberized. The fibers are then pulled as usually pneumatically and deposited on a foraminous mat or band to form the non-woven fabric. The fibers produced in the Meltblowing and Spunbond processes are microfibers as defined above.

The fibers used can also contain coform materials and in addition can be conjugated and biconstituent fibers as defined above, in this case, the stabilization additive package can be added to any of the polymers used as long as the stabilization additive package is in a layer exposed to sunlight. For example, in the chaos of the conjugate sheath / core fibers, the stabilization additive package must be mixed with the sheath polymer.

The fabric of this invention can also be a multilayer laminate. In this case, the stabilization additive package must be mixed with the polymer used in the outermost layers of the fabric. The stabilization additive package can also be mixed with the polymer or polymers of the inner layer or layers but still will not expect less than one effect in these layers, since these are not exposed to sunlight as much as the outer layers.

Base weights for car covers are generally between about 68 grams per square meter and 244 grams per square meter. In a typical nonwoven fabric laminate car cover, the spunbonded and usually outer layers can have a basis weight of between 17 grams per square meter and 119 grams per square meter and may have one or more inner layers having a basis weight between about 7 grams per square meter and 51 grams per square meter.

It is also possible, when the fabric of this invention is used as a multilayer cover, to skew the base weights of the outer layers where the outer layer closest to the carriage is of a lower basis weight than the other outer layer., or more particularly, wherein the layer closest to the carriage has a basis weight varying from about 40 to 75% of the base weight of the layer furthest from the carriage. It is believed that biasing base weights to move the heavier weight basis layer away from the car, and therefore expose it to sunlight, increases long-term stress resistance simply by putting more material into the layer most vulnerable to deterioration. It has also been found advantageous to use a lower denier fabric for the layer closest to the car compared to the farthest layer of the car. The reason for this seems to be that a thinner layer against the car reduces the abrasion caused by the wind and by the acts of covering and discovering the car and therefore produces less loss in the brightness of the car paint after a prolonged use, compared to a thicker fiber layer against the car. An example of the ranges of base weights of the layers of such a fabric is from 68 to 105 gsm for the layer away from the surface of the car, from 10 to 25 gsm for the inner layers of laminate and from 27 to 60 gsm for the layer against the car. Even more particularly, a carriage cover having, for example, a general basis weight of 163 gsm, can have 4 layers with base weights as follows, starting with the layer against the carriage: 44 gsm, 17 gsm, 17 gsm, 85 gsm (1.3 osy, 0.5 osy, 0.5 osy, 2.5 osy) where the outer layers will be joined by spinning and the inner layers formed of meltblown.

Multiple layers are linked in some way as they are produced in order to give them structural integrity and make them into a finished product. The joint can be achieved in a number of ways known in the art such as entangled yarn, perforation, ultrasonic bonding, adhesive bonding and thermal bonding.

The thermoplastic polymers which may be used in the practice of this invention may be any known to those skilled in the art as being commonly used in meltblowing and spinbonding. Such polymers include polyolefins, polyesters and polyamides, and mixtures thereof, more particularly polyolefins such as polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers, and butene copolymers and mixtures thereof.

The spunbonded layers of the fabric of this invention are preferably a polyolefin, more particularly polypropylene having a melt flow rate (MFR) of between 9 and 1000 and even more particularly within 9 and 100. The melt flow rate it is an indication of the viscosity of the polymer with a higher number indicating a lower viscosity. It should be noted that in multilayer fabrics, the layers do not need to be spun from the same polymer. Suitable polypropylenes for spin-bonded layers are commercially available, for example from PF-301 and PF-305 from Himont Corporation of Wilmington, Delaware.

In a laminate or multi-layer fabric having meltblown layers, they are also preferably of polyolefin, particularly of polypropylene, and like the spunbonded layers, they do not require to be made of the same polymer. A polypropylene having a melt flow rate of between 200 and 2000 will be adequate. Particularly suitable polypropylenes are PF-015 available from Himont or E5A75 from Shell Chemical Company of Houston Texas.

The stabilizer additive package of the invention is an internal additive, as it differs from a typically applied additive, and is mixed with the polymer prior to extrusion of the polymer. The package includes hinged amines and a pigment based on bismuth vandata.

The hindered amines are discussed in United States Patent No. 5,200,443 issued to Hudson and examples of such amines are Hostavin TMN 20 from Hoescht Celanese Corporation of Somerville, New Jersey, Cyasorb UV-3668 from Cytec Industries, Inc., of West Patterson, New Jersey and Uvasil-299 from Great Lakes Chemical Corporation of West Lafayette Indiana. A particularly suitable bonded mine is that commercially available from Chimassorb® 944 FL of Ciba-Geigy Corporation of Hawthorne, New York and having a CAS registration number 70624-18-9. It has been found that to be effective, the mined mine must have a molecular weight of between about 500 and 3500.

The bonded amine light stabilization material can be added to the polymers at an amount between about 0.25 and 2.5 percent by weight. For example, in fabrics joined by spinning, the amount should be between 0.5 and 2.5 percent by weight and between about 0.25 and 2% by weight in the melt blow. More particularly, the bonded mine must be present in an amount of between about 1 and 1.5% by weight in fabrics joined by spinning and of about 1% by weight in fabrics formed by meltblowing.

The pigment based on bismuth vandate can be added to the polymers at an amount between about 0.1 and 3% by weight. In fabrics joined by spinning, for example, the amount should be between 0.1 and 2.0% by weight and between about 0.3 and 3.0% by weight in the melt blow. More particularly, the bismuth vandate may be present in an amount of between about 0.75 and 2.0% by weight in spin-bonded fabrics, and one percent by weight of about 1.0 in melted blow fabrics. The bismuth vanadium-based pigments are commercially available from Ciba-Geigy Corporation of Hawthorne, New York, under the brand name IRGA-COLOR YELLOW 2GTM.

Bismuth vandate is known in the art, because it improves color fastness, for example it reduces discoloration, improves heat resistance, resistance to the environment and freedom of migration, for example, bleeding. The inventor is not aware of any teaching of reduced deterioration of the tensile strength in non-woven fabrics with exposure to sunlight due to the bismuth vandate in conjunction with the amine light stabilizers locked.

The bismuth vandalism pigments can be made, for example, in accordance with US Pat. Nos. 4,937,063 and 5,399,335 issued to Sullivan and assigned to Ciba-Geigy and any other method known in the art. Patent No. 4,937,063 describes calcining the starting materials, then wet grinding these and treating them with an alkali. U.S. Patent No. 5,399,335 discloses making a mixture of 10-50 percent by weight of a solid bismuth compound and a solid vandato compound at a molar ratio of Bi: V of 1: 1-1: 0.8 with one percent by weight of 90-50 of a mineral acid solution at a pH of 1, wet grind the suspension at 0-100 ° C until the bismuth and vandate turn into a yellow pigment of bismuth and vandata and then isolate the vanadium bismuth from the mineral acid.

The bismuth vandata and amine Chimassorb® 944 FL were incorporated into the polypropylene pellets by the Standrige Color Corporation of Social Circle, Georgia. Two commercially available products are sold under the designation SCC-11354, which has 25% by weight of bismuth vandalism pigment and SCC-8784 which has 15% by weight of HALs.

The fabric of this invention may also have topical treatments applied to it for more specialized functions. Such topical treatments and their methods of application are known in the art and include, for example, antistatic treatments and the like, applied by spraying etc.

It has been found that a fabric having a HAL and a pigment based on bismuth vandalis has photostability of an improved durability long sought in outdoor fabrics of this type. The increased length of the fabric of this invention provides cost savings for consumers.

The aforementioned characteristics of the fabric of this invention are illustrated in the following examples, the test results of which are given in Table 1. Note that example 3 is an example of the package and fabric of this invention and that the others they are not. Note also that the percentages of pigment weight represent the amount of pigment represent the amount of pure pigment present in the mixture in Examples 2,3 and 5-9, and the percentages of weight of amine represent the amount of pure amine in the mix in all the examples.

EXAMPLE 1 A cloth bound by polypropylene yarn Himont PF-304 was produced. Prior to extrusion, 1.0% by weight of Chimassorb® 944 FL amine was added and mixed thoroughly with the polymer. No pigment was added to the polymer of this example. The fabric produced had a basis weight of about 69 gsm. The fabric was subjected to the South Florida test mentioned above and tested periodically for tensile strength. The data of this test is given in Table 1 and illustrated graphically in Figure 1 where the data in this example is divided by the initial stress resistance to arrive at a percent retention of an original tensile strength, which is shown by the circles.

EXAMPLE 2 A spunbonded fabric was produced from Himont PF-403 polypropylene. Prior to extrusion, 1.0 percent by weight of a calcined metal option and 1.0% by weight of Chimassorb® FL amine were added and fully combined with the polymer. Calcined metal oxide was designated V-9119 by Ferro Chemical Company of Bedford, Ohio and consisted of zinc and iron oxides. The fabric produced had a basis weight of about 2 ounces per square yard. The fabric was subjected to the South Florida test described above and was periodically approved for stress resistance. The data of this test are given in Table 1 and illustrated graphically in Figure 1 where the data was divided by the initial stress resistance to reach a percent of retention of the original tensile strength and which was shows by squares.

EXAMPLE 3 A fabric bound by polypropylene yarn Himont Pf-304 is produced. Prior to extrusion about 0.5 percent by weight of bismuth vandal pigment and about 1% by weight of Chimassorb® 944 FL were added and thoroughly mixed with the polymer. This was achieved by the addition of about 2.0 percent by weight of SCC-11354 from Standrige Color Corporation 6.7% by weight of SCC-8784 to the required amount of polypropylene. The fabric produced had a basis weight of about 2 osy. The fabric was subjected to the South Florida test described above and periodically tested for retention. The data for this test are in Table 1 and illustrated graphically in Figure 1 where the data in this example was divided by the initial tensile strength to arrive at a percentage of original tensile strength retention and that show by triangles.

EXAMPLE 4 A cloth bound by Himont polypropylene yarn PF-301 was produced. Before the extrusion they were added 0. 75% by weight of amine Chimassorb® 944 FL and completely mixed with the polymer. No pigment was added to the polymer of this example. The fabric produced had a basis weight of about 2 osy. The fabric was subjected to the South Florida test described above and was periodically approved for stress resistance. The data of this test are in the Table 1 and graphically illustrated in Figure 2 where the data of this example was divided by the initial stress resistance to arrive at a retention percentage of the original tensile strength and which is shown by open squares.

EXAMPLE 5 A spin-bonded fabric of Himont polypropylene PF-301 was produced. Prior to extrusion, 4.0% by weight of V-9119 of Ferro Corporation and 0.75% by weight of amine Chimassorb® 944 FL were added and mixed thoroughly with the polymer. The fabric produced had a basis weight of about 2 osy. The fabric was subjected to the fabric described above from South Florida and tested periodically for tensile strength. The data from this test are in Table 1 and graphically illustrated in Figure 2 where the data in this example was divided by the initial stress resistance to reach a percent retention of the original tensile strength in which is shown by open triangles.

EXAMPLE 6 A cloth bound by Himont polypropylene yarn PF-301 was produced. Prior to extrusion, 0.5% by weight of Irgazin Yellow 3RLT organic pigment from Ciba-Geigy Corporation and 0.75% by weight of Chimassorb® 944 FL amine were added and thoroughly mixed with the polymer. The fabric produced had a basis weight of about 2 osy. The fabric was subjected to the South Florida test described above and periodically tested for tensile strength. The data for this test are in Table 1 and are illustrated graphically in Figure 2 where this example is divided by the initial tensile strength to arrive at a percent retention of the original strength and which is shown by circles.

EXAMPLE 7 A spin-bonded fabric was produced from Himont polypropylene PF-301. Prior to extrusion, 0-5% by weight of Cromophthal Amarillo #G organic pigment from Ciba-Geigy Corporation and 0.75% Amine Chimassorb® 944 FL were added and mixed thoroughly with the polymer. The fabric produced had a basis weight of 2 osy. The test was submitted to the South Florida test described above and was periodically approved for resistance to stress. The data for this test are in Table 1 and are illustrated graphically in Figure 2 where the data in this example is divided by the initial tensile strength to give a percent to retention of the original tensile strength and which it is shown by asterisks.

EXAMPLE 8 A fabric bound by polypropylene yarn Himont PF-301 was produced before extrusion, 0.5 percent by weight of phthalocyanine blue organic pigment from Ciba-Geigy Corporation and 0.75 percent of Chimassorb® 944 FL amine were added and mixed thoroughly with the polymer. The fabric produced had a basis weight of about 2 osy. The fabric was subjected to the South Florida test described above and tested periodically for tensile strength. The data for this test are in Table 1 and were illustrated graphically in Figure 2 where the data in this example was divided by the initial stress resistance to reach a percent retention of the original tensile strength and the which is shown by solid squares.

EXAMPLE 9 A cloth bound by Himont polypropylene yarn PF-301 was produced. Prior to extrusion, 0.5 percent by weight of BR Cromophtal red organic pigment from Ciba-Geigy Corporation and 0.75% Chimassorb® amine were added and mixed thoroughly with the polymer. The fabric produced had a basis weight of about 2 osy. The fabric was subjected to the South Florida test described above and tested periodically for resistance to retention. The data for this test are in Table 1 and are illustrated graphically in Figure 2 where the data in this example is divided by the initial tensile strength to arrive at a percent retention of the original tensile strength and the which are shown by solid triangles.

TABLE 1 Examples Percent Resistance to Stress Resistance Months in South Florida 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 Example 1 88 91 76 74 69 61 67 48 57 47 36 44 43 36 37 35 38 Example 2 76 71 67 65 56 58 56 45 46 42 39 42 43 42 38 38 41 Example 3 69 80 90 78 82 80 77 73 85 75 64 66 41 66 55 49 57 Example 4 91 79 84 66 78 88 84 73 60 59 68 53 48 47 60 33 25 Example S 100 85 98 80 85 96 85 86 81 82 79 76 86 80 85 79 69 Example 6 100 72 68 72 62 57 54 34 36 37 39 35 19 25 0 Example 7 84 54 37 37 20 17 0 Example 8 93 83 74 60 51 62 53 37 33 33 28 32 21 24 37 18 0 Example 9 91 57 49 43 40 34 31 33 16 16 0 15 It is clear from the foregoing results that the stabilizer additive package of this invention (Example 3) has a desirable and unique combination of attributes. This greatly increases the photostability of a non-woven fabric. It should be noted that Example 5, which has good photostability, was at an extremely high pigment loading level. Nonwovens with such high pigment loads are very difficult to manufacture due to problems with nozzle clogging and even undue mixing. The pigment amounts above 3 percent by weight are generally confined to highly controlled manufacturing conditions such as the laboratory or pilot units. In addition, Example 2, using the same pigment as Example 5, but at a lower charge, did not exhibit improved photostability over non-pigmented Example 1.

Although only a few example embodiments of this invention have been described in detail, those skilled in the art will readily appreciate that many modifications to the exemplary embodiments are possible without departing materially from the teachings and novel advantages of this invention. Therefore, all such modifications are intended to be included within the scope of this invention as defined in the clauses that follow. In the claims, the media clauses plus function are intended to cover the structures described herein, as by carrying out the function mentioned and not only the structural equivalents but also the equivalent structures. Thus, even though a screw and a nail may not be equivalent structures in the sense that a nail employs a cylindrical surface to secure joints to wooden parts, while a screw employs a helical surface, in the environment of the fastening Wood parts, a screw and a nail can be equivalent structures.

It should be noted that many patents, applications or publications referred to herein are incorporated by reference in their entirety.

Claims (16)

1. A package of stabilizer additive for non-woven fabrics comprising a pigment based on bismuth vandata and a hindered amine light stabilizer.

2. The package as claimed in clause 1, characterized in that the bound amine has a molecular weight of between about 500 and 3500.

3. The package as claimed in clause 1, characterized in that the bismuth vandate is added to a polymer of non-woven fiber before extrusion in an amount of between about 0.1 and 3 percent by weight based on the weight of the fabric and said amine locked in an amount of between about 0.25 and 2.5 percent by weight based on the weight of the fabric.

4. A nonwoven fabric comprising the package as claimed in clause 1 and a polymer selected from the group consisting of polyolefins.

5. The non-woven fabric as claimed in clause 4, characterized in that the polyolefin is a polypropylene.

6. The non-woven fabric as claimed in clause 4, characterized in that said fabric is a first layer of a fabric joined by spinning.

7. The non-woven fabric as claimed in clause 4, characterized in that said fabric has a basis weight of between about 17 and 119 gsm.

8. The nonwoven fabric as claimed in clause 6, further characterized in that it comprises a second layer of spunbonded cloth attached to said first spunbonded layer.

9. The nonwoven fabric as claimed in clause 8, further characterized in that it comprises at least one layer of meltblown fabric interposed between said first and second spunbonded and bonded layers thereto.

10. The non-woven fabric as claimed in clause 9, wherein the layers joined by spinning contain the package of clause 1.

11. The non-woven fabric as claimed in clause 9, characterized in that said second layer has a basis weight of between about 40 to 75 percent of said basis weight of the first layer.

12. The non-woven fabric as claimed in clause 8, characterized in that said second layer is made of filaments of a denier lower than the filaments lower than the filaments of said first layer.

13. A protective cover comprising the fabric as claimed in clause 9.

14. The protective cover as claimed in clause 13, characterized in that said protective cover is a carriage cover.

15. The protective cover as claimed in clause 13, characterized in that said protective cover is a boat cover.

16. A protective cover for vehicles comprising spunbonded fibers thermally bonded with a blend of polypropylene, bismuth vandate in an amount of between about 0.1 and 3 percent by weight based on the weight of the web and amine locked in an amount of between around 0.25 and 2.5% by weight based on the weight of the fabric.