MXPA97008465A - Non-woven-pelic laminates - Google Patents

Abstract

The present invention relates to a film / nonwoven laminate consisting essentially of: a first component which is a multilayer film comprising a first surface layer of a heterophasic polymer in an amount of from about 5 to about of 40 percent by weight of said first component, a second surface layer of a polymer having a lower coefficient of friction than said first surface layer in an amount of from about 5 to about 40 percent by weight of said first component, and a lower layer in an amount of from about 20 to about 90 percent by weight of said first component wherein said inner layer contains an opacity enhancer, a second component which is a bonded non-woven fabric with yarn comprising a heterophasic polymer and having at least one layer, wherein said first and second components are attached thermally together to form a laminate wherein said first surface layer is located near said second component and said laminate has a peel strength of 180 ° of at least 120 gram

Description

NON-WOVEN-FILM LAMINATES BACKGROUND OF THE INVENTION For many years, thermoplastic resins have been extruded to form fibers, films and fabrics. The most common thermoplastics for these applications are polyolefins, particularly polypropylene and polyethylene, even though each material has its characteristic advantages and disadvantages in relation to the properties desired in the final products.

Non-woven fabrics are of a type of product which can be made from such polymers and are useful for a wide variety of applications, such as personal care products, diapers, women's hygiene products and products. of incontinence, the products for the control of the infection, the garments and many others. The non-woven fabrics used in these applications are often in the form of laminates having several numbers of layers of meltblown fabric, spunbond fabric and / or films such as spin-bonded / meltblown / bonded laminates. by spinning (SMS), SMMS laminates, laminated by spinning / film (SF) and SFS laminates and still laminates having 6 or more layers.

A particular disadvantage of SF laminates is that they can be delaminated under certain conditions. Such delamination is, of course, undesirable, since it can result in product failure. There is a need for a spin-bonded / film laminate which is lightweight and thin but which provides adequate adhesion between the layers so that delamination does not occur.

It is another object of this invention to provide laminates having at least one layer of a non-woven fabric with at least one layer of a film wherein the laminate exhibits more delamination or peel strength than similar laminates hitherto known.

SYNTHESIS OF THE INVENTION A multilayer laminate composed of a layer of a film and a layer of a non-woven fabric is provided herein. The film is made of polymers and has as a surface a semicrystalline / amorphous or "heterophasic" polymer, a polymer of filler type, less expensive, optional internal, and like the other surface, a polymer with a lower coefficient of friction. The nonwoven fabric can be a meltblown or blown web, preferably spunbonded and preferably also including a heterophasic polymer. The film and the non-woven components are joined together using a thermal spot bond preferably while the film is stretched at least 5 percent. Such a laminate can be made in a personal care product such as a diaper, training pants, absorbent underwear, incontinence products for adults, and products for women's hygiene.

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

As used herein the term "microfiber" 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, or more particularly, Microfibers can have an average diameter of from about 2 microns to about 40 microns. Another frequently used expression of fiber diameter is denier, which is defined as grams per 9,000 meters of a fiber. For example, the diameter of a polypropylene fiber given in microns can be converted to denier by squared, and multiply the result by 0.00629, therefore, a polypropylene fiber of 15 microns has a denier of about 1.42 (152 X 0.00629 = 1.415 ).

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 spinning organ with the diameter of the fibers. extruded filaments then being rapidly reduced as by, for example, in U.S. Patent No. 4,340,563 issued to Appel et al., and U.S. Patent No. 3,692,618 issued to Dorschner et al. United States of America number 3,802,817 granted to Matsu i and others, United States of America patents number 3,338,992 and 3,341,394 granted to Kinney, United States Patent number 3,502,763 granted to Hartman, the United States patent of North America number 3,502,538 granted to Levy, and the patent of the United States two of North America number 3,542,615 granted to Dobo and others. Spunbond fibers are generally non-sticky when they are deposited on a collecting surface. Spunbonded fibers are generally continuous and have diameters larger than 7 microns, more particularly, 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 capillary matrix vessels, usually circular and thin as melted threads or filaments into gas streams. at high speed (for example air) which attenuate the filaments of the melted thermoplastic material to reduce its 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 collecting surface to form a fiber web of meltblown material discharged at random. Such a process is described, for example, in US Pat. No. 3,849,241 issued to Butin. The meltblown fibers are microfibers which may be continuous or discontinuous, are generally smaller than 10 microns in diameter, and are generally sticky when deposited on a collecting surface.

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

As used herein the term "heterophasic" with reference to a polymer means a thermoplastic polymer which has both elastic properties. Such polymers are sometimes referred to as "plasto-elastic" or "elastoplastic" polymers and may be semicrystalline / amorphous in nature. These polymers have a compromise of elastic properties and mechanical resistance and can easily be transformed into manufactured articles through the use of devices and processes normally used for thermoplastic materials.

As used herein the term "monocomponent" fibers 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 coloring additive, antistatic properties, lubrication, hydrophilicity, etc. have been added are excluded. These additives, for example, titanium dioxide for coloration are generally present in an amount of less than 5 percent by weight and more typically of about 2 percent by weight.

As used herein, the term "conjugated fibers" refers to fibers which are 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 can be monocomponent fibers. The polymers are arranged in distinct zones essentially permanently placed across the cross section of the conjugated fibers and extend continuously along the length of the conjugated fibers. The configuration of such a conjugate fiber may be, for example, a sheath / core arrangement where one polymer is surrounded by another or may be a side-by-side arrangement or an arrangement of "islands in the sea". Conjugated fibers are shown in U.S. Patent No. 5,108,820 issued to Kaneko et al., In U.S. Patent No. 5,336,552 issued to Strack et al., And in U.S. Patent No. 5,382,400. awarded to Pike and others. For two monocomponent 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 along the entire length of the fiber, instead of usually forming fibrils or protofibrils which start and end at random. The biconstituent fibers are sometimes referred to as multi-constituent fibers. Fibers of this general type are discussed in, for example, U.S. Patent No. 5,108,827 issued to Gessner. Conjugated and biconstituent fibers are also discussed in the text "Mixtures and Compounds of Polymers" by John A. Manson and Leslie H. Sperling, copyright 1976 by Plenum Press, a division of Plenu 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 where the components are immiscible but have been compatibilized. The terms "misibility" and "inmissibility" are defined as mixtures having negative and positive values, respectively, for the free energy of mixing. In addition, "compatibilization" is defined as the process for modifying the interfacial properties of an immiscible polymer mixture in order to make it an alloy.

As used herein, the term "stitch-bonded" means for example, sewing of a material according to U.S. Patent No. 4,891,957 issued to Strack et al. Or to the U.S. Patent Number 4,631,933 awarded to Cerey, Jr.

As used herein, "ultrasonic bonding" means a process carried out, for example, by passing the fabric between a sonic horn and an anvil roll as illustrated in U.S. Patent No. 4,374,888 issued to Bornslaeger. .

As used herein, "hydroentanglement" means a bonding process performed, for example, by subjecting a fabric to high pressure water jets which entangle the fibers together and thereby increase the integrity of the fabric.

As used herein, "thermal spot bonding" involves passing a fabric of fibers that are to be joined between a heated calender roll and an anvil roll. The calendered roll is usually, though not always, patterned in some way that the entire fabric is not bonded across its entire surface. As a result of this, various patterns for calendering rolls have been developed for functional as well as aesthetic reasons. An example of a pattern that has points is that of Hansen Pennings, or pattern "H &P "with about 30 percent area bonded with about 200 joints / square inch as taught in U.S. Patent No. 3,855,046 issued to Hansen and Pennings.The pattern H &P has a point or pin square of joint areas where each bolt has a side dimension of 0.965 millimeters, a separation of 1,778 millimeters between bolts, and a bond depth of 0.584 millimeters.The resulting pattern has a joined area of about 29.5 percent. Typical point union pattern is the Hansen and Pennings joint pattern or expanded "EHP" that produces a 15 percent joint area with a square bolt having a side dimension of 0.94 millimeters, a bolt spacing of 2,464 millimeters and a depth of 0.991 millimeters Another typical point union pattern designated "714" has the square point joining areas where each bolt has a side dimension of 0.0 23 inches, a spacing of 1,575 mm between the bolts, and a joint depth of 0.838 mm. The resulting pattern has a bound area of about 15 percent. Yet another common pattern is the C-star pattern which has a bound area of about 16.9 percent. The C-star pattern has a bar design in the transverse direction interrupted by leak stars. Other common patterns include a diamond pattern with slightly off-centered and repetitive diamonds and a wire wave pattern looking like its name suggests as a window grid. Typically, the percent bond area varies from about 10 percent to about 30 percent of the area of the laminated fabric. As is well known in the art, point bonding holds the layers of laminated material together as well as imparting integrity to each individual layer by bonding the filaments and / or fibers within each layer.

As used herein, the term "joining window" means the temperature range of the calendering rolls used to join together the non-woven fabric, upon which such bonding is successful. For polypropylene spunbonded, this bond window is typically from about 132 degrees centigrade to about 154 degrees centigrade. Below 132 degrees Celsius the polypropylene is not hot enough to melt and join and up to around 154 degrees Celsius the polypropylene will melt excessively and may stick to the calendering rollers. The polyethylene has an even narrower connecting window.

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 a fabric, for example an address generally perpendicular to the machine direction.

As used herein, the term "tapered" or "tapered" refers interchangeably to a method for elongating a non-woven fabric, generally in the machine direction, to reduce its width in a controlled manner to a desired amount. The controlled stretching can take place under room temperature, cold or higher temperatures and is limited to an increase in the overall dimension in the direction that is being stretched to the elongation required to break the fabric which in most cases is around from 1.2 to 1.4 times. When it relaxes, the fabric retracts to its original dimensions. Such a process is described, for example, in U.S. Patent No. 4,443,513 issued to Meitner and Notheis, and in U.S. Patent Nos. 4,965,122, 4981,747 and 5,114,781 issued to Morman.

As used herein the term "recover" refers to a contraction of a stretched material upon the termination of a pressing force after stretching of the material by application of the pressing force. For example, if the material having an unpressed and relaxed length of one inch will be lengthened by 50 percent by stretching to a length of one and a half inches, the material would have a stretched length that is 150 percent of its relaxed length. If this example stretched material were to contract, that is to recover to a length of one and a tenth of an inch after the release of the stretching and pressing force, the material would have recovered 80 percent (0.4 inches of its elongation.

As used herein, the terms "elastic" and "elastomeric" when referring to a fiber, film or cloth means a material which with the application of a pressing force, is stretchable to a pressed and stretched length which is of a at least about 150 percent about one and a half times its relaxed length not stretched; and which will recover at least 50 percent of its elongation with the release of the pressing and stretching force.

As used herein, the term "pledge" means any type of non-medically oriented clothing which may be worn. This includes industrial workwear and coveralls, undergarments, breeches, shirts, jackets, gloves, socks and the like.

As used herein, the term "infection control product" means medically oriented articles such as surgical gowns and drapes, face masks, head covers such as caps, surgical caps and caps, items for shoe stores such as covers of shoes, covers of boots and slippers, bandages of wounds, sterilization wraps, cleaners, garments such as lab coats, covers all, aprons and jackets, bedding for the patient, sheets for stretcher and cradle and the like.

As used herein, the term "personal care product" means diapers, training pants, absorbent underwear, incontinence garments for adults and products for the hygiene of women. Such products generally have an outer cover which is resistant to liquid penetration and which also provides a visual barrier and is aesthetically pleasing. An outer cover for a personal care product, for example a diaper, may also serve as a "positioning" area or attachment point for the tape closure means and may also provide a fastening means for the closure systems of hook and curl wherein the outer covering material can be the hook or loop means.

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 that is frequently left outside such as grills, equipment for patio and garden (mowers, rototrilladoras, etc.) and furniture for meadow, as well as covers for floor, tablecloths and covers for lunch area.

TEST METHODS Melt flow rate: The melt flow rate (MFR) is a measure of the viscosity of a polymer. The melt flow rate is expressed as the weight of material which flows from a capillary vessel of known dimensions at a specific cut-off rate or load for an adapted period of time and is measured in grams / 10 minutes at 230 degrees Celsius. according to, for example, the ASTM 1238 test, condition E.

Peel Test: In the peel or delamination test a laminate is tested with respect to the amount of tension force that will pull the layers of laminate apart. The values for the peel strength are obtained using a specified cloth width, usually 4 inches (102 mm), a clamp width and a constant extension rate. The film side of the specimen is covered with tape or other suitable material in order to prevent the film from tearing during the test. The masking tape is only on one side of the laminate and does not contribute to the peel strength of the sample. The sample is delaminated by hand by an amount sufficient to allow it to be placed in position. The specimen is grasped in, for example, an Instron model TM apparatus, available from Instron Corporation, 2500 Washington Street, Canton, MA 02021, or a Thwing-Albert model INTELLECT II apparatus available from the Thwing-Albert Instrument Company, 10960 Dutton Road. , Philadelphia, Pennsylvania 19154, which has clamps of 76 mm long. The sample specimen is then pulled and separated 180 degrees apart and the tensile strength is recorded in grams.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph of a nuclear magnetic resonance (NMR) spectrum of Himont KS-050 with ppm from 0 to 60 as the horizontal axis and using tertiaryimethylsilane as the carrier and carried out in a known manner over a Bruker AC-250 NMR spectrometer.

Figure 2 is a graph of infrared examination (IR) or random block copolymer curve KS-050 Himont having a wave number of from 400 to 2,000 as the horizontal axis and a percentage of transmittance from 35 to 101 as the vertical axis.

DETAILED DESCRIPTION Thermoplastic polymers are useful in the production of films, fibers and fabrics for use in a variety of products such as personal care articles, infection control products, garments and protective covers. An example of such material is a nonwoven fabric / film laminate which functions as a liquid impervious retainer.

The film / nonwoven laminate can be used, for example as an outer cover material for diaper. The outer cover material for diapers should perform the function of retaining body fluids and should also be aesthetically pleasing to the eye of the consumer, for example, the material should look attractive to the eye and should also mask the view of fluids and material who is holding the diaper. An outer cover for a personal care product, for example, a diaper may also serve as a "landing area" or attachment point for the tape closure means and may also provide securing means for a closure system of hook and curl wherein the outer cover material may be the hook or the curl means. Such functionality requires that the laminate remain together without failure, an attribute which has been a problem for the previous nonwoven / film laminates.

The inventor has discovered a way to achieve the result of a nonwoven laminate / film which remains together as a better laminate than the previous materials. The present invention uses a non-woven fabric, preferably a spin-bonded component thermally bonded to a particular film. The film component is composed of a surface layer which is made of a semicrystalline / amorphous or "heterophasic" polymer and the other surface which is preferably made of a lower coefficient of friction polymer. The film component also preferably has an inner layer of a less expensive polymer, such as a polyolefin, to reduce the overall cost. The pigments are also preferably present in the inner layer.

The film component layers are extruded together using any method known in the art as being effective. The film component is produced in a thickness of from about 0.3 mils to about 0.8 mils. If three layers are present in the film component, for example, the film component is a co-extruded film A / B / C, it is preferred that the surface layers each be from about 3 to about 40 percent by weight. weight of the total component and that the inner layer contributes to the balance. In a particular embodiment, the film component is extruded using an "A" layer which is semi-crystalline / amorphous or a heterophasic polymer in an amount of about 10 percent by weight, a low coefficient of friction layer on the other surface outer or "C" layer in an amount of about 10 percent by weight, and a polypropylene polymer in layer "B" with the remainder.

The "A" layer is made of polymers which are heterophasic in nature. Suitable polymers are described in the European patent application EP 0444671 A3 (based on the application number 91103014.6), the European patent application EP 0472946 A2 (based on the application number 91112955. 9), the European patent application EP 0400333 A2 (based on the application number 90108051.5), the patent of the United States of America number 5,302,454 and the patent of the United States of America number 5, 367,927. Other suitable heterophasic polymers include EnBA, ethylene / vinyl acetate copolymers, ethylene / methyl acetate copolymers, EAA and other copolymers, and terpolymers of polypropylene, polyethylene and polybutylene as well as elastomers such as SEBS, SEPS, SBS, and urethanes which fill the definition of being heterophasic.

European Patent Application EP 0444671 A3 teaches a composition comprising first, 10-60 percent by weight of a polypropylene homopolymer having an isotactic Index greater than 90 or a crystalline copolymer of propylene with ethylene and / or other alpha olefins containing more than 85 percent by weight of propylene and having an isotactic Index greater than 85; second, 10-40 percent by weight of a copolymer containing predominantly ethylene, which is insoluble in xylene at room temperature; and third, 30-60 percent by weight of an amorphous ethylene-propylene copolymer, which is soluble in xylene at room temperature and contains 40-70 percent by weight of ethylene, wherein the propylene polymer composition it has a ratio between the intrinsic viscosities, in tetrahydronaphthalene at 135 degrees Celsius, from the part soluble in xylene and from the part insoluble in xylene at room temperature from 0.8 to 1.2.

European Patent Application EP 0472946 A2 teaches a composition comprising first, 10-50 weight percent of a polypropylene homopolymer having an isotactic index greater than 80 or a crystalline copolymer of propylene with ethylene, a CH2 = CHR alpha-olefin wherein R is an alkyl radical of 2-8 carbons or combinations thereof, which copolymer contains more than 85 weight percent propylene; second, 5-20 weight percent of a copolymer containing ethylene which is insoluble in xylene at room temperature; and third, 40-80 percent by weight of a fraction of ethylene-propylene copolymer or other CH2 = CHR alpha-olefin, wherein R is an alkyl radical of 2-8 carbons, or combinations thereof, and optionally, minor proportions of a diene, the fraction containing less than 40 percent by weight of ethylene and being soluble in xylene at room temperature and having an intrinsic viscosity of from 1.5 to 4 dl / g; wherein the percent by weight of the sum of the second and third fractions with respect to the total polyolefin composition is from 50 to 90 percent and the proportion by weight of the second to third fraction is lower than 0.4 percent .

European patent application EP 0400333 A2 shows a composition comprising first, 10-60 percent by weight of a polypropylene homopolymer having an isotactic index greater than 90 or a copolymer of crystalline propylene with ethylene and / or an olefin CH2 = CHR in where R is 2-8 carbon alkyl radicals containing more than 85 weight percent propylene and having an isotactic Index greater than 85; second, 10-40 percent by weight of a crystalline polymer fraction containing ethylene, which is insoluble in xylene at room temperature; and third, 30-60 percent by weight of an amorphous ethylene-propylene copolymer optionally containing small amounts of a diene, which is soluble in xylene at room temperature and contains 40-70 percent by weight of ethylene; where the composition has a modulus of flex less than 700 MPa, a tension set at 75 percent, less than 60 percent, stress strain greater than 6 MPa and IZOD elasticity grooved at minus 20 degrees and minus 40 degrees Celsius higher of 600 J / m.

U.S. Patent No. 5,302,454 shows a composition comprising first, 10-60 percent by weight of a polypropylene homopolymer having an isotactic index greater than 90 or a crystalline propylene copolymer with an olefin CH 2 = CHR wherein R is an alkyl radical of 2-6 carbons, or combinations thereof, containing more than 85 percent by weight of propylene and having an isotactic index greater than 85; second, 10-40 weight percent of a crystalline polymer fraction containing ethylene and propylene and having an ethylene content of from 52.4 percent to about 74.6 percent and which is insoluble in xylene at room temperature; and third, 30-60 percent by weight of an ethylene-propylene copolymer optionally containing small proportions of a diene, soluble in xylene at room temperature and containing 40-70 percent by weight of ethylene; wherein the composition has a modular flexure less than 700 MPa, a tension set at 75 percent, less than 60 percent, stress strain greater than 6 MPa, and a slotted IZOD elasticity at minus 20 degrees and minus 40 degrees centigrade greater than 600 J / m.

U.S. Patent No. 5,368,927 shows a composition comprising first, -60 percent by weight of a polycrystalline homopolymer having an isotactic index greater than 80 or a crystalline propylene copolymer with ethylene and / or an alpha-olefin having 4-10 carbon atoms, containing more than 85 percent by weight of propylene and having an isotactic index greater than 80; second, 3-25 weight percent of an ethylene-propylene copolymer soluble in xylene at room temperature; and third, 15-87 percent by weight of an ethylene copolymer with propylene and / or an alpha-olefin having 4-10 carbon atoms, and optionally a diene containing 20-60 percent ethylene and completely soluble in xylene at the room temperature.

Other polymers which may be used for layer "A" include block copolymers such as polyurethanes, copolyether esters, polyether polyamide block copolymers, ethylene / vinyl acetates (EVA), the block copolymers having the general formula ABA 'or AB as copoly (styrene / ethylene-butylene), styrene-poly (ethylene / propylene) -styrene, styrene-poly (ethylene-butylene) -styrene, (polystyrene / poly (ethylene-butylene) / polystyrene, poly (styrene / ethylene-butylene / styrene) and the like.

Useful resins include block copolymers having the general formula ABA 'or AB, wherein A and A' are each an end block of a thermoplastic polymer which contains a styrenic group such as poly (vinyl arene) and wherein B is a middle block of elastomeric polymer such as a conjugated diene or a lower alkene polymer. The block copolymers of type A-B-A 'may have different or the same thermoplastic block polymers for blocks A and A', and the block copolymers present are intended to encompass the linear, branched and radial block copolymers. In this regard, radial block copolymers can be designated (AB) under mX, where X is a polyfunctional atom or a molecule in which each (AB) m-radiates from X in a manner that A is an end block . In the radial block copolymer, X may be an organic or inorganic polyfunctional atom or a molecule and m is an integer having the same value as the functional group originally present in X. It is usually at least 3, and is frequently 4 or 5, but it is not limited to this. Therefore, in the present invention, the term "block copolymer" and particularly block copolymer "ABAA '" and "AB", is intended to encompass all block copolymers having such rubberized blocks and said thermoplastic blocks as discussed above , which can be extruded, and without limitation as to the number of blocks. The film can be formed of, for example, block copolymers of (polystyrene / poly (ethylene-butylene) / polystyrene). Commercial examples of such copolymers are, for example, those known as KRATON® materials which are available from the Shell Chemical Company of Houston, Texas. KRATON® block copolymers are available in several different formulas, a number of which are identified in U.S. Patent Nos. 4,663,220 and 5,304,599, incorporated herein by reference.

Polymers composed of a tetrablock copolymer A-B-A-B can also be used in the practice of this invention. Such polymers are discussed in U.S. Patent No. 5,332,613 issued to Taylor et al. In such polymers, A is a thermoplastic polymer block and B is a hydrogenated isoprene monomer unit to essentially one unit of poly (ethylene-propylene) monomer. An example of such tetrablock copolymer is a styrene-poly (ethylene-propylene) -styrene-poly (ethylene-propylene) block copolymer or SEPSEP available from Shell Chemical Company of Houston Texas, under the trade designation KRATON® G-1657.

Other exemplary materials which may be used include polyurethane materials such as, for example, those available under the trademark ESTAÑE® from BF Goodrich S Company or MORTHANE® from Morton Thiokol Corporation, block copolymer polyether polyamide such as, for example, that known as PEBAX® available from Atochen Inc., Polymers Division (RILSAN®), Glen Rock, New Jersey and polyester materials such as, for example, those available under the trade designation HYTREL® from E. I. DuPont De Nemours & Company Suitable polymers also include copolymers of ethylene and at least one vinyl monomer such as, for example, vinyl acetates, unsaturated aliphatic monocarboxylic acids, and esters of such monocarboxylic acids. These copolymers are described in, for example, U.S. Patent No. 4,803,117.

Polymers particularly suitable for layer "A" are commercially available under the trade designation "Catalloy" from Himont Chemical Company of Wilmington, Delaware. Specific commercial examples are Catalloy® KS-084P and Catalloy® KS 057P. The Himont KS-057P has a melt flow rate of 30 and a density of 0.9 gm / cc according to page 673 of the Buyer's Guide and Plastic Technology Manufacturers' Handbook, 1994/95 by Bill Publications, from 355 Park Avenue, South, New York, New York, 10010.

Polymers can be characterized in a number of ways, two of which are nuclear magnetic resonance (NMR) and infrared (IR) examination. Figures 1 and 2 show these examinations of a preferred heterophasic polymer in the practice of this invention, Himont KS-050, prior to the cracking of the peroxide to produce KS-057P. Peroxide cracking is a process for raising the melt flow rate of a polymer and an example of such a process is taught in U.S. Patent No. 5,271,883 issued to Timmons.

The NMR spectrum and the IR curve of the polymer shown to be KS-057P have about 3 percent of random ethylene molecules and about 9-10 percent of ethylene block molecules.

The "B" layer may be a copolymer or polypropylene polymer. Since this layer is relatively thick, most of the opacity can be added to this layer. Opacity can be added through the use of, for example, Ti02 or CaC03. Commercially available opacity enhancers are, for example, Techmer PM 18074 E Ti02 concentrate and SCC concentrate 13602 Ti02 from Standridge Chemical Company. These concentrates are approximately 70 percent TiO2 from DuPont in a 30 percent LDPE carrier.

The "C" layer provides the surface for the film. It is important that layer C has a lower coefficient of friction than layer A for ease of winding, unwinding and film handling through the production steps to convert the nonwoven / film laminate into a final product as a diaper This can be achieved by including a large proportion of polypropylene in this layer. Typical polypropylenes which may be used are Escorene® 3445 from Exxon Chemical Company or E5D47 from Shell Chemical Company.

The various film layers may also have small amounts of additives present to improve processability such as low density polyethylene (LDPE) such as those available from Quantum Chemical Company under the designation NA 334 or those available from Rexena under the designation 1058 LDPE. Many similar LDPE polymers are commercially available.

The nonwoven fabric component of this invention is a spunbonded material preferably and preferably between about 0.3 and 1 ounce per square yard (11 grams per square meter to 34 grams per square meter). The polymers which can be used to produce the spin-bonded component are the thermoplastic polymer such as polyolefins, polyamides, and polyesters, preferably the polyolefins and even more preferably a mixture including a heterophasic polymer in an amount of about 50 percent by weight. weight. More particularly, the non-woven fabric may be composed of a polypropylene blend such as Escorene® 3445 from Exxon Chemical Company or E5D47 from Shell Chemical Company and about 40 weight percent of a heterophasic polymer such as Catalloy® KS-057P. . Even more particularly, the non-woven fabric can be composed of a mixture of high crystalline polypropylene and about 20 percent by weight of Catalloy® KS-057P.

The non-woven component and the film component are joined together using the thermal point bond preferably after the film stretched by about 60 to 65 percent in the machine direction. This stretching and joining can be carried out according to the patent application of the United States of America number 07 / 997,800 and the European patent application EP 0604731 Al (based on the application number 93117426.2) and commonly assigned to the assignee of this registration , Kimberly-Clark Corporation. Briefly, this method involves extending a first stretchable layer from an original length to an expanded length with the expanded length being at least 5 percent greater than the original length. Depending on the degree of stretching, the first stretchable layer can be permanently deformed. Then, a second layer of material is placed in juxtaposition with the first layer while the first layer is still in the expanded length and the two layers are then clamped together at a plurality of spaced-spaced joining sites to form the laminate which includes a plurality of joined and unattached areas. Once the laminate has been formed, the first layer is allowed to relax to a third length which is usually longer than the first length of the first layer. As a result of the attachment of the second layer to the first layer while the first layer is in an expanded state, once the laminate contracts, the first layer is folded and collected, thus forming a bulkier material in comparison to a simple non-stretched laminate of the same two materials. Generally, the stretching is carried out by winding the film around a number of rollers with the rear rollers running at a higher speed than that of the initial rollers, resulting in a stretching and thinning of the film. Such stretching can reduce the thickness of the film by about a third or more. For example, a film according to this invention can be produced which has a thickness of 0.6 mil before stretching and 0.4 mil after stretching.

In addition, a compatible adhesive resin can be added to the extrudable compositions described above to provide the self-bonding adhesive materials. Any adhesive resin can be used which is compatible with the polymers and can withstand high processing temperatures (eg, extrusion). If the polymer is mixed with the processing aids such as, for example, polyolefins or extension oils, the adhesive resin may also be compatible with those processing aids. Generally, hydrogenated hydrocarbon resins are preferred adhesive resins because of their better temperature stability. The adhesives from the REGALREZ ™ and ARKON ™ P series are examples of hydrogenated hydrocarbon resins. The light ZONATAC ™ 501 is an example of a hydrocarbon terpene. REGALREZ ™ hydrocarbon resins are available from Hercules Incorporated. Resins of the ARKON ™ P series are available from Arakawa Chemical (United States of America) Incorporated. Adhesive resins such as those described in U.S. Patent No. 4,787,699, incorporated herein by reference, are suitable. Other adhesive resins which are compatible with the other components of the composition and which can withstand the high processing temperatures, can also be used.

The nonwoven component of the laminates of this invention can be produced by meltblowing or spin bonding processes which are well known in the art. These processes generally use an extruder to supply the melted thermoplastic polymer to a spinning organ wherein the polymer is fiberized to give fibers which may be short or longer in length. The fibers are then pulled, usually pneumatically, and deposited on a movable foraminous band or web to form the non-woven fabric. The fibers produced in the meltblown and meltblown processes are microfibers as defined above.

In order to illustrate the advantages of the laminates according to the invention, the following examples and controls were developed. All laminates are thermally bonded using a pattern roller at 116 degrees centigrade and an anvil roller at 93 degrees centigrade.

CONTROL A type A / B / A film was thinned and stretched from 0.6 to 0.4 mil and thermally laminated with a C-star bond pattern to a polypropylene spun bonded layer of 17 grams per square meter made of Escorene® 3445. The film layers had a ratio of 30/40/30. The layer "A" was made from 65 percent Catalimon® 71-1 from Himont, 25 percent from 3445 Exxon, 5 percent low density polyethylene (NA 334 Quantum Chemical) and 5 percent concentrate Ti02 (Ampacet 110210, 50/50 mixture in polypropylene). The layer "B" was made from 25 percent of Catalimon® 71-1 from Himont, 30 percent from 3445 from Exxon, 5 percent from low density polyethylene (NA 334 from Quantum Chemical) and 40 percent from concentrate Ti02.

EXAMPLE 1 A type A / B / C film was stretched and thinned from 0.6 to 0.4 mil and thermally laminated with a C-star bonding pattern to a layer of polypropylene spunbonded material of 17 grams per square meter made of Escorene® 3445. The film layers had a ratio of 10/80/10. The "A" layer was made from 85 percent of Catalimon® KS-084P from Himont, 10 percent from 3445 from Exxon, and 5 percent from NA 334 LDPE from Quantun Chemical. Layer "B" was made from 40 percent Catalimon® KS-084P from Himont, 43 percent from 3445 from Exxon and 17 percent from Ti02 concentrate available from Standridge Chemical Company of Social Circle, Georgia under the SCC trade designation 13602. Layer "C" was made from 35 percent of Catalimon® KS-084P from Himont, 60 percent from 3,445 from Exxon, and 5 percent from NA 334 LDPE from Quantum Chemical.

EXAMPLE 2 A type A / B / C film was stretched and thinned from 0.6 to 0.4 mil and thermally laminated with a C-star bonding pattern to a layer of polypropylene spunbonded material of 17 grams per square meter made of Escorene ® 3445. The film layers had a ratio of 10/80/10. The "A" layer was made of 93 percent of Catalimon® KS-084P from Himont and 5 percent of 1058 LDPE from Rexene Chemical. Layer "B" was made from 40 percent Catalimon® KS-084P from Himont, 43 percent from 3445 from Exxon, and 17 percent from Ti02, available from the Techmer Company under the trade designation PM 18074E. The "C" layer was made from 40 percent Catalomon® KS-084P from Himont, 55 percent from 3445 from Exxon, and 5 percent from 1078 LDPE from Rexene.

The control and examples were tested for delamination according to the peeling test described above and the results are given in Table 1.

T A B L A 1 Displays 180 ° Peel Resistance Control 60-70 grams Example 1 120-130 grams Example 2 126-142 grams The Table shows that the unique combination of the film layers of this invention improves the peel strength significantly, at more than 120 grams. This is an important breakthrough in the technology of personal care products and will produce products that are more durable and more aesthetically pleasing to the consumer.

Claims (17)

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

1. A film / nonwoven laminate comprising: a first component which is a film comprising on a surface a heterophasic layer and on a second surface a layer of a polymer having a lower coefficient of friction; Y a second component which is a non-woven fabric having at least one layer.

2. The laminate as claimed in clause 1 characterized in that said film and nonwoven components are thermally bonded together to form said laminate.

3. The laminate as claimed in clause 2 characterized in that said film is stretched at least 5 percent before thermal bonding.

4. The laminate as claimed in clause 1 characterized in that said layer of heterophasic film is composed of a polymer having the NMR spectrum of Figure 1.

5. The laminate as claimed in clause 1 characterized in that said film component further comprises an inner layer composed of a polyolefin.

6. The laminate as claimed in clause 5 characterized in that said film component surface layers together comprise from 10 to 80 weight percent of said film component and said inner layer comprises from 20 to 90 percent by weight. weight of said film component.

7. The laminate as claimed in clause 1, characterized in that it has a peel strength greater than 120 grams as measured by the method established in the specification.

8. The laminate as claimed in clause 1 characterized in that said nonwoven component comprises a spunbonded thermoplastic polymer fabric.

9. The laminate as claimed in clause 8 characterized in that said polymer comprises a heterophasic polymer.

0. A personal care product selected from the group consisting of diapers, training pants, absorbent underwear, incontinence products for adults, and feminine hygiene products including an outer covering comprising the laminate of clause 1.

11. The personal care product as claimed in clause 10 which is a diaper.

12. The personal care product as claimed in clause 10 characterized in that this is an absorbent undergarment.

13. The personal care product as claimed in clause 10, characterized in that this is a product for adult incontinence.

14. The personal care product as claimed in clause 10, characterized in that this is a product for feminine hygiene.

15. A film / nonwoven laminate consisting essentially of: a first component which is a film comprising on a surface a layer of heterophasic polymer in an amount of from about 5 to about 40 percent by weight of said first component, a second surface layer of a polymer having a coefficient of lower friction in an amount of from about 5 to about 40 percent by weight of said first component and an inner layer in an amount of from about 20 to about 90 percent by weight of said first component, and a second component which is a spunbonded nonwoven fabric comprising a heterophasic polymer and having at least one layer, wherein said components are thermally bonded together to form a laminate wherein said heterophasic film layer is located near the second component.

16. The laminate as claimed in clause 15 characterized in that said laminate has a peel strength of at least 120 grams.

17. A method for producing a film / nonwoven laminate having a good peel strength comprising: stretching at least five percent a first component which is a film comprising on a surface a layer of heterophasic polymer in an amount of about 5 to about 40 percent by weight of said first component, a second surface with a layer of a polymer having a lower coefficient of friction in an amount of from about 5 to about 40 percent by weight of said first component, and an inner layer in an amount of from about 20. to about 90 percent by weight of said first component, and bringing said first stretched component into contact with a second component which is a spunbonded nonwoven fabric comprising a heterophasic polymer and having at least one layer, and thermally bonding said components to form a laminate wherein said layer of heterophasic film is located near the second component and wherein said laminate has a peel strength of at least 120 grams. SUMMARY A multilayer laminate composed of a layer of a film and a layer of a non-woven fabric is provided herein. The film is made of polymers and has on one surface a semicrystalline / amorphous or "heterophasic" polymer, a less costly, optional internal filler-type polymer, and like the other surface, a polymer with a lower coefficient of friction. The non-woven fabric may be a spin-bonded or melt-blown fabric, preferably spun-bonded and preferably also including a heterophasic polymer. The film and non-woven components are joined together using the thermal spot bond preferably while the film is stretched at least 5 percent. Such a laminate can be made in a personal care product such as a diaper, training pants, absorbent underwear, incontinence products for adults, and products for women's hygiene.