MXPA99006196A - Breathable laminate including filled film and continuous film - Google Patents

Abstract

A breathable multi-layer film laminate (20) including microporous filled film (22) bonded to continuous film (16, 26). A support layer such as a fibrous web can be adhered to the film laminate on one or both surfaces.

Description

LAMINATE WITH BREATHING CAPACITY INCLUDING A FILLED MOVIE AND A CONTINUING MOVIE FIELD OF THE INVENTION The present invention is directed to laminates of multilayer film with breathability including a filled film and a continuous stretch film. In addition, the present invention is directed to a method for making such laminates.

BACKGROUND OF THE INVENTION The present invention is directed to breathable laminates that include at least one microporous film and a continuous and stretchable film and process for making them. Such materials have a wide variety of uses, especially in the areas of limited use and disposable items.

Films have traditionally been used to provide barrier properties in disposable articles or limited use. By limited disposable use it is meant that the product and / or the component are used only a small number d times, or possibly only once before being discarded. Examples of such products include, but are not limited to, health-care and surgical products such as surgical suits and covers, disposable work clothing such as coveralls and lab coats, and absorbent products. for personal care such as diapers, underpants, incontinence garments, sanitary napkins, bandages, cleaners, packaging and the like. In absorbent personal care products such as infant diapers and adult incontinence products, the films are used as outer covers for the purpose of preventing body waste from contaminating clothes, sheets and other aspects. of the surrounding environment d use. In the protective clothing area including hospital gowns, the films are used to prevent the cross-exchange of microorganisms between the user and the patient. In the packaging area, the films are used to allow the passage of H20 and 02 but not of the microorganisms.

The lamination of the films has been used to create materials which are both waterproof and somewhat like cloth type in appearance and texture. The outer covers on the disposable diapers are but an example. In this aspect, reference may be made to the commonly assigned United States of America patent 4,818,600 dated April 4, 1989 and United States patent 4,725,473 to the United States of America dated February 16, 1988. The coats and the surgical covers are other examples. See in this regard the jointly assigned patent of the United States of America 4,379,102 dated April 5, 1983.

A primary purpose of the film in such laminations is to provide the liquid barrier properties. There is also a need for such laminates to be breathable so that they have the ability to transmit moisture vapor. The costumes made of these breathable and / microporous films are more comfortable to wear by reducing the moisture vapor concentration and the consequent foot moisturization underneath the costume item. However, the pore size in breathable films can be very large, especially in protective clothing applications, such as industrial medical garments, where the penetration of chemical liquid presents a risk of contamination to the patient. user. In addition, the micropore-containing film can allow the passage of chemical vapors and / or viruses and therefore reduce the effectiveness of protective clothing.

The conventional process for obtaining a microporous film capable of breathing has been to stretch a thermoplastic film containing a filler. The microvoids are created by the filler particles during the stretching process. The film is usually heated before these pulling processes to make the film more plastic malleable. This pulling or stretching also orients the molecular structure within the film which increases strength and durability in a stretched direction. The molecular orientation caused by stretching is desired to improve durability.

A film can be stretched in the direction of the machine or in the direction transverse to the machine. E stretch of the film in the transverse direction and particularly challenging because the forces can be applied to the edges of the film to make it stretch The stretch frames are commonly used. And contrast, the stretching of the film in the direction of the machine is relatively easy. It is only necessary to increase and pull or the speed ratio between two rollers while the film is in the heated and plastic state. There is a problem of durability, however, with the films stretched unidirectionally, one is in the direction of the machine or the cross direction. Unidirectional stretching caused a molecular orientation in the stretched direction. This resulted in films that are easily torn or broken along that dimension. For example, a film oriented in the direction of the machine has a propensity to tear break along the direction of the machine. Also, the tension characteristics of the film are dramatically increased in the machine direction, but the tension resistance in the transverse direction is essentially lower than that of the machine direction.

These problems of durability with unidirectionally oriented and stretched films are well known. Two approaches are commonly used to make obvious the product durability problems that result from this highly isotropic resistance characteristics. The first is to stretch-orient the film in both the cross direction and the direction of the machine. The films that have stretched biaxially have more balanced resistance properties. The second approach is to combine in a laminate a layer the film oriented in the direction of the machine with a layer of the film oriented in the transverse direction. This approach is a consumer of time limitant in size and expensive. There is therefore a need for a lightweight breathable film laminate stretched unidirectionally using low cost materials and process that provide the laminate with both the ability to breathe, the barrier and the durability in use that are desired.

In addition, precise control of the stretching process is usually required in order to avoid creating holes that are very large, as previously mentioned, the formation of undesirably large pores will lower the hydro head of the films to unacceptably low levels thus causing the runoff of liquids, molecules and microorganisms that cause odor. There is therefore a need for a flexible and breathable laminate and a process that provides a laminate with the barrier properties with the ability to breathe and the notch and comfort that are desired.

SYNTHESIS OF THE INVENTION The present invention relates to a multilayer film laminate including an oriented filled film and at least one continuous film. The filled film includes a polymeric resin and a filler that is at least 10 percent by volume of said polymeric resin. Preferably, the filled film contains from about 25 to about 50 volume percent of the filler. Continuous elastic film is attached to the ant filled stretch film. The elastic film is permeable to water vapor and perhaps impermeable to the molecules that cause it. Preferably, the continuous elastic film is either continuously uni or knitted to the filled film. The laminate is stretched so that the film filled by itself has a water vapor transmission value of at least 450 g / square meter-24 hours. The stretch laminate has a water vapor transmission rate of at least 200 g / square meter-24 hours.

In an application, the elastic continuous film layer has an immediate recovery length that is at least about 50 percent of its extension after a cyclic stretch that achieved a stretched length of about 150 percent of the n length pressed. In another application, the elastic continuous film d the present invention can have an immediate recovery length that is at least about 50 percent d its elongation length followed after a cycle d stretching that achieved a stretched length of about 20 percent of the length not pressed. In one embodiment, the filled film layer is also elastic and has a permanent settling so that the micropores remain open. In another embodiment, the continuous elastic film has a permanent settlement that is less than the permanent settlement of the filled film.

The resulting oriented multilayer film laminate is preferably flexible, breathable and liquid repellent, and provides a sweeping of unwanted molecules and microorganisms. The choice of material included in the filled film layer or layers and the continuous film or films as well as the type of bond used between the layers affects the stretchability, appearance and permeability of the rolled product.

In a first application, the elastic continuous film provides a support and reinforcement structure to the microporous filled film. In a second application, the continuous film remains a total barrier to liquids a barrier to undesirable vapors even where the lamina includes a film filled with large micropores. In a third application, the multilayer film laminate includes an elastic continuous film bonded to a non-elastic filled film so that the rolled product is stretchable in the orientation direction. In a fourth application, the multilayer film laminate is joined to another support layer such as a nonwoven fabric.

Such multi-layer film laminates as the complete article or a component have a wide variety of uses including, but not limited to, applications in packaging, protective garment articles including industrial workwear as well as absorbent articles for care personnel including diapers, underpants, sanitary napkins, incontinence devices, bandages and the like. These same films can also be used in medical garments such as surgical suits and covers as well as in various articles of clothing either as the entire article or simply as a component thereof.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of a filled film continuously attached to a continuous film according to the present invention.

Figure 2 is a schematic diagram of a filled film knitted to a continuous film according to the present invention.

Figure 3 is a schematic diagram of a process for preparing a multilayer film laminate according to the present invention.

Figure 4 is a schematic diagram of a cloth employing the lamination of multilayer films of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED INCORPORATIONS The present invention is directed to multilayer film laminates including continuous elastic films and filled films.

The term "continuous film" as used herein describes a monolithic film that will not contain holes ah after stretching, so that the film provides a barrier and thus a high hydro head value.

The term "continuous bonding" as used herein describes a bond between two film surfaces wherein the bond is essentially unbroken. In contrast, the term "point bonding" as used herein refers to a bond between two film surfaces where the bond is discontinuous at discrete points of the surfaces.

Referring now to Figure 1, an unstretched multilayer film laminate 10 of the present invention is illustrated to contain a filled film layer 12 containing a polymeric material and fillers 15. Filled film layer 12 is continuously bonded a continuous film layer 16 containing an elastomeric material. With the stretching, a multi-layered oriented film laminate 20 results. The laminate 2 contains microvoids or holes 23 created by the fillers 15 during the stretching process in the filled and oriented film layer 22 and in the oriented continuous film layer. 26 The polymeric material of the filled film layer 12, 22 can be an elastic or non-elastic material. The term "elastic" as used herein means any material which, with the application of a pressing force is stretchable, that is, stretchable (or extendable) to a pressed and stretched length which is at least about 150% of its length not pressed and relaxed and which will be recovered by at least 50 percent of its elongation with the release of the stretching and stretching force. A hypothetical example would be a 1-inch sample of a material which is stretchable to 1.50 inches and which, having been lengthened 1.50 inches and released, will recover to a length of no more than 1.25 inches. Many elastic materials can be stretched for much more than 50 percent of their relaxed length for example, to 100 percent or more, and many of these will recover to their original relaxed length, for example, within 105 percent of their original relaxed length. , with the release of the stretching force.

As used herein, the term "non-elastic" refers to any material which does not fall within the definition of elastic given above.

Examples of the polymeric materials useful in the filled film 10 include non-elastic thermoplastic polymers, elastomers, plastomers and combinations thereof.

The non-elastic thermoplastic materials useful in the present invention are extrudable thermoplastic polymers such as polyamides, nylons, polyesters, polyolefins or a mixture of polyolefins including homopolymers, copolymers and mixtures thereof.

The elastomers useful in the practice of this invention can be those made of copolymers such as polyurethanes, copolyethers, polyether polyamide copolymers, ethylene vinyl acetate (EVA), block copolymers having the general formula ABA 'or AB com 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 elastomeric resins include block copolymers having the general formula ABA 'or AB wherein A and A' are each a thermoplastic polymer end block which contains a styrenic moiety such as poly (vinyl arene) and wherein B is a middle block of elastomeric polymer such as a conjugated diene or a lower alken polymer. The block copolymers of the type A-B-A 'may have the same or different thermoplastic block polymers for the A and A' "blocks and the block copolymers present which are intended to span the branched and radial linear block copolymers. In this aspect, radial block d-copolymers can be designated (A-B) m-X, wherein X is a polyfunctional atom or molecule and in which each (A-B) m- radiates X in a manner that A is an end block. In the radial block copolymer, X can be an organic or inorganic polyfunctional atom or molecule and m is an integer having the same value as the functional group originally present in X. Est is usually at least 3, and is frequently 4 or 5 but it is not limited to this. Therefore, in the present invention the expression "block copolymer" and particularly "A-B-A" 'block copolymer "A-B", is intended to encompass all block copolymers having rubberized blocks or thermoplastic blocks. Commercial examples of such elastomeric copolymers are, for example, those known with KRATON® materials which are available from Shell Chemica Company of Houston Texas. KRATON block copolymers are available in several different formulas, a number of which are identified in the patents of the United States of America numbers 4,663,220, 4,323,534, 4,834,738, 5,093,422 5,304,599, incorporated herein by reference.

Polymers composed of an elastomeric tetrablock copolymer A-B-A-B may also be used in the practice of this invention. Such polymers are discussed in U.S. Patent 5,332,613 issued Taylor et al. In such polymers, A is a thermoplastic polymer block and B is a hydrogenated isoprene. An example of such a tetrablock copolymer is styrene-poly (ethylene-propylene) styrene-poly (ethylene-propylene) or elastomeric block copolymer SEPSEP available from Shell Chemical Company of Houston Texas.

Other exemplary elastomeric materials which may be used include polyurethane elastomeric materials such as, for example, those available under the trade mark ESTAÑE® de B.F. Goodrich & Company or MORTHANE® of Morto Thiokol Corporation, elastomeric polyester materials such as, for example, those available under the trade designation HYTREL® of E. I. DuPont De Nemours & Company, those known co or ARNITEL® formerly available from Akzo Plastics of Arhem, The Netherlands and now available from DSM d Sittard, The Netherlands.

Another suitable material is a polyester block amid copolymer having the formula: I I I I HO - [- C- A-C-O-PE-O -] "- H wherein n is a positive integer, PA represents a polyamide polymer segment, and PE represents a polymer polyether segment. In particular, the polyether block amide copolymer has a melting point of from about 15 degrees centigrade to about 170 degrees centigrade, as measured in accordance with ASTM D-789; a melt index of from about 6 grams per 10 minutes to about 25 grams per 10 minutes, as measured in accordance with ASTM D-1238, conditioned Q (load of 235 C / l kilogram); a modulus of elasticity and bending from about 20 Mpa to about 200 Mpa, as measured according to ASTM D-790; a tensile strength at breaking from about 29 MPa to about 33 MPa as measured in accordance with ASTM D-638 and a final elongation at break from about 50 percent to about 700 percent as measured by ASTM D-638 standard. A particular incorporation of the polyether block d-amide copolymer has a melting point of about 152 degrees centigrade as measured in accordance with ASTM D 789; a melt index of about 7 grams per minute as measured according to ASTM D-1238, condition (load 235 C / l kilogram); a modulus of elasticity in flexion d around 29.50 MPa, as measured according to norm ASTM D-790; a resistance to breaking stress d around 29 MPa, a measurement in accordance with ASTM D 639; and an elongation at break of about 65 percent as measured in accordance with ASTM D-638. Tale materials are available in various grades under the PEBAX® trade designation of ELF Atochem, Inc. of Glen Rock, New Jersey Examples of the use of such polymers can be found in U.S. Patent Nos. 4,724,184 4,820. 572 and 4,923,742 incorporated herein by reference to Killian and others and assigned to the same assignee of this invention. The elastomeric polymers also include the 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. The elastomeric copolymers and the formation of the elastomeric non-woven fabrics of those elastomeric copolymers are described in, for example, U.S. Patent No. 4,803,117.

The thermoplastic copolyester elastomers include the copolyester esters having the general formula: I I I I I I H- ([0-G-0-C-C6H4-C] b- [O- (CH2), - 0- C-C6H4-C] m) "-0- (CH2), -OH wherein "G" is selected from the group consisting of poly (oxyethylene) -alpha-omega-diol, poly (oxypropylene) -α or ega-diol, poly (oxytetramethylene) -alpha, or ega-diol and "a" and "b are positive integers including 2, 4 and 6," m "and" n "are positive integers including 1-20, such materials generally have an elongation at break from about 60 percent to 750 percent when measured in accordance with ASTM D-638 norm and a melting point of from about 35 degrees F to about 400 degrees F (176 to 205 degrees Celsius) when measured in accordance with ASTM D-2117 Commercial examples of such copolyester materials are, for example, those known as ARNITEL® formerly available from Akzo Plastics of Arhem, The Netherlands now available from DSM of Sittard, The Netherlands, or that known as HYTREL® which are available from E. I DuPont De Nemours of Wilmington Delaware.

The plastomers useful in the practice of this invention have physical characteristics of both thermoplastics and non-elastic elastomers. Examples of useful plastomers include the metallocene-catalyzed ethylene-based materials.

The term "metallocene-catalyzed ethylene-based materials" as used herein includes those polymer materials that are produced by the polymerization of at least ethylene using constrained geometry-bound metallocenes., a class of organometallic complexes, such as catalysts, for example, a common metallocene catalyst is ferrocene, a complex with a target placed in the form of a sandwich between two cyclopentadienyl ligands (Cp). Metallocene process catalysts include bis (n-butylcyclopentadienyl) d-titanium dichloride, bis (n-butylcyclopentadienyl) zirconium dichloride bis (cyclopentadienyl) scandium chloride, bis (indenyl zirconium dichloride, bis (methylcyclopentadienyl) d-titanium dichloride, bis (methylcyclopentadienyl) zirconium dichloride cobaltocene, cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride, isopropyl (cyclopentadienyl, -1-fluoroenyl) zirconium dichloride, olibdocene dichloride niquelocene, niobocene dichloride, ruthenocene, dichloride d-titanocene, zirconocene chloride hydride, dichloride d zirconocene, among others A more exhaustive list of such compounds is included in U.S. Patent No. 5,374,696 issued to Rosen et al and assigned to Do Chemical Company. United States of America number 5,064.80 granted to Stevens and others and also assigned to D ow.

The metallocene process, and particularly catalysts and catalyst support systems are the subject of a number of patents. U.S. Patent No. 4,542,199 issued to Ka insky and another discloses a process wherein MAO is added to toluene, and the metallocene catalyst of the formula generates (cyclopentadienyl) 2MeRHl wherein Me is a transition metal Hal is a halogen and R is cyclopentadienyl or alkyl Cl to C6 radical or a halogen, is added, and then is added to ethylene to form the polyethylene. U.S. Patent No. 5,189,192 issued to LaPointe et al. And assigned to Dow Chemical discloses a process for preparing addition polymerization catalysts through metal core oxidation. U.S. Patent No. 5,352,749 issued to Exxon Chemical Patents, Inc. describes a method for polymerizing monomers in fluidized beds. U.S. Patent No. 5,349.10 discloses chiral metallocene compounds and preparations thereof by creating a chiral center mediant enantioselective hydride transfer.

Co-catalysts are materials such as methyl aluminoxane (MAO) which is the most common, other compounds containing alkyl aluminum and boron com tris (pentafluorophenyl) boron, lithium tetrakis (pentafluorophenyl) boron, and dimethylanilinium tetrakis (pentafluorophenyl) boron . The research is continuing on other co-catalytic systems or the possibility of minimizing or even eliminating aluminum alkyl due to product contamination and handling issues. The important point is that the metallocene catalyst is activated or ionized to a cationic form for the reaction with the monomer or monomers to be polymerized.

The metallocene-catalyzed ethylene-based polymers used in the present invention impart stretch and recovery property to the film. Preferably, the metallocene-catalyzed ethylene-based polymers selected from the ethylene and butene copolymers, the ethylene and the copolymers 1-hexene, the ethylene and 1-octene copolymers and combinations thereof. In particular the preferred materials include the elastomeric metallocene copolymers of Engage ™ brand of ethylene and 1-octen available from DuPont / Dow Elastomers of Wilmington, Delaware. Particularly preferred materials also include the marc Exact ™ metallocene-derived copolymers and terpolymers available of Exxon Chemical Company of Houston, Texas In accordance with the present invention, the continuous cap 16, 26 is a stretchable material. As used herein, the term "stretchable material" as used to describe material in the continuous layer encompasses those materials which tend to retract after being stretched to a stretch ratio of at least 1.5 or 50 percent. S believes that the proportion of stretch or minimum necessary to achieve a water vapor transmission rate of at least 300 grams / square meter / 24 hours. Examples of extensible materials include elastomers, certain polyolefins and plastomers. The elongating polyolefins include polyethylenes (especially low linear density polyethylenes), polypropylenes and ethylene propylene copolymers with one another and with other alpha olefins.

In another application, where the filled film 12 is elastic, it is preferred that the filled film polymeric material 12 has a permanent settling. The term "permanent settlement" as used herein is a physical characteristic of the polymeric material so that when the material having an original length is stretched and the stretched force is removed, the sample does not return to its original length if some length is greater than the original length. characteristic permanent settlement will allow the relaxed movie 27 to retain the microvoids 23 produced by stretching.

In addition to the polymeric material, the filled film layer 10 also includes a filler which allows the development of micropores during orientation of the film. As used herein, a filler means that it includes particles and other forms of materials which can be added to the polymer and is capable of dispersing uniformly throughout the film. The film will usually contain at least 10 percent (%), preferably about 25 about 50 percent, filler based on the total volume of the polymer resin. According to the present invention the particle size of the filler is not critical to the functionality of the product. Both organic and inorganic fillers are contemplated to be within the scope of the present invention as long as they do not interfere with the film forming process.

Examples of fillers include calcium carbonate (CaC03), various kinds of clays, silica (Si02), alumina, barium sulfate, sodium carbonate, talc magnesium sulfate, titanium dioxide, zeolites, aluminum sulfate, powders of type cellulose, diatomaceous earth, magnesium sulfate, magnesium carbonate, barium carbonate, kaolin mica, carbon, calcium oxide, magnesium oxide, aluminum hydroxide, pulp powder, wood dust, cell-derived polymer particles, chitin and Chitin derivatives. The filler particles can optionally be coated with a fatty acid, such as stearic acid and behenic acid which can facilitate the free flow of the particles (volume) and their ease of use or dispersion in the polymer matrix.

Filled film 12 and 22 illustrated in Figure 1 is continuously bonded to the continuous film 16 and 2 This type of bonding can be achieved by, for example, applying a continuous layer of adhesive between the layers 12 and 22. Other types of continuous bonding include, for example, thermal bonding. -Extrusion of layers 12 and 22. Further, continuous bonding can be effected by providing each film layer 12 and 16 with polymeric materials having the glutinizant incorporated therein.

Alternatively, as shown schematically in Figure 2, the film layers 32 and 36 in the laminate of the present invention can be knitted together. Figure 2 shows a laminate 30 containing a full film 32 attached to a continuous film 36 at the knit joints 38. The laminate 30 is then stretched and results in a laminate 4 containing the extended filled film layer containing microvoids 42 formed by the filler particles 3 during stretching. Once the laminate 40 is allowed to relax, the resulting laminate 50 contains a microporous filled film layer 52 with a preferential retraction, for example, with a collapsed resin material 57 which is "puckered upwards." The resulting retracted laminate can then It is easily stretched to its original stretch length.This preferential retraction provides a more cloth-like feel for the microporous filled film side 52 of the 50 laminate. In contrast, as shown in Figure 1, the resin material 27 remained. spread on a filled film layer 22 which is continuously bonded to a continuous layer 26. The point junctions 38 can be generated, for example, using adhesives, ultrasonic bonding or thermal bonding.

The type of union between the continuous filled film and the type of material of the filled film affects the characteristics of the laminated product of multiple layer film. In one application, where the filled film 3 is elastic, the polymeric resin constituting the filled film 32 preferably has a permanent settling property that is greater than that of the continuous film layer 36 in order to obtain the "frowing" effect. " In another application, where the filled film 32 is not elastic and the cloth type sensation is preferred, the knit bond of the filled film 32 to the continuous film 36 will achieve preferential retraction in the retracted resin 57 of the laminate 50. In yet another application where the cloth-like feel is not desired, it is preferred that the filled film 32 include an elastomeric material having permanent settling characteristics equivalent to those of the continuous film layer 36.

In addition, the type of joint also contributes to the stretchability of the product of the multilayer film laminate. As used herein, a product with a relaxed length C after it is initially oriented from an original length A to a stretched length B is "stretchable when it can be pulled back to length B repeatedly. Referring to Figure 2, if the film is filled The elastic laminate 20 is stretchable, in contrast to Figure 1, if the non-elastic filled film 22 is continuously bonded to an elastic continuous film 26, the resulting laminate 20 is knitted to an elastic continuous film 56. The resulting laminate 20 is stretchable. it is feasibly not s stretchable as the laminate previously discussed 50.

Of course, it should be understood that the present invention includes a multilayer film laminate (shown) wherein a plurality of filled film layers are bonded to one another and are secured to one or more continuous film layers. In addition, the multiple layer laminate may include alternating layers of filled film and continuous film bonded to each other.

Generally, it has been possible to produce laminates with a water vapor transmission rate (WVTR) of at least around 200 grams per square meter for 2 hours, measured by the ASTM E-96-80 vapor transmission rate test. of water with the Celgar® 2500 as control In general, the factors that affect the amount of stretching include the amount of filler, the stretching conditions of the film (for example if ambient or elevated temperatures are carried out), the orientation ratio and the film thickness. Preferably, the water vapor transmission rate of the multiple film laminate of the present invention which can be used as a component of a disposable limited use article is from about d 1000 to about 5000 g / square meter / 24 hours, depending on the of the application of the article.

A hydro head value of a film or laminate is mediated by the liquid barrier properties of the material. The hydro head test determines the height of liquid (in centimeters) that the fabric will support before a predetermined amount of liquid passes through it. A fabric with a higher hydro head reading indicates that it has a greater barrier to penetration of the water. liquid water than a cloth with a lower hydro head. The hydro head test is carried out according to the federal test standard 19IA method 5514.

The permeability of the multiple film laminate will be limited by the permeability characteristic of the continuous film layer or layers in the laminate. As used herein, the permeability of a film or laminate is described by the permeability coefficient of the laminated film. This coefficient has the dimensions described in the equation I given below: (I) P = [(amount of permeation) x (film / thickness d laminate)] / [(area) x (time) x (pressure drop through d film / laminate)] The type of undesirable molecule for which s look for the barriers will define in an extension the composition the continuous film layer in the laminated product. Permeability of the film layer is generally influenced by factors including its dense crystallinity, molecular mass and cross-linking in the elongate material as well as the amount of orientation, additive type in the layer. The selection of the appropriate elongate material will therefore allow selective permeability, for example water vapor molecules but not, for example, d ammonia vapor molecules through the resulting laminate.

The desired properties can be obtained by first preparing a polymeric resin of a material as described above, filling the resin with filler, extruding a filled film made of the filled resin; and secondly preparing an elastomeric resin, extruding a continuous film of the elastomeric resin, and thirdly joining the filled film to the continuous film Alternatively, the filled film / stretched film can be prepared by coextrusion, a process illustrated in Figure 3. Then, stretch or orient the rolled film / continuous film in at least one direction, usually the machine direction. As explained in more detail below, the resultant film laminate is breathable and has barrier properties as well as increased strength properties in the orientation direction.

In general, a process for forming a filled film / continuous film laminate 100 is shown in FIG. 3 of the drawings. Referring to the figure, the laminate 10 is formed of a film coextrusion apparatus 140 ta as a blow or setting unit. Typically apparatus 140 will include two extruders 141 and 141a. The filled resin including the polymeric material and the filler was prepared in a mixer 143 and directed to the extruder 141. The elastomeric resin was prepared in another mixer 143a and was directed to extruder 141a. The laminate 100 is co-extruded into a pair of cooling or pressure point rollers 142 one of which may have a pattern such as to impart an etched pattern to the newly formed laminate 100.

From the film extrusion apparatus 140, the laminate 100 is directed to a film stretching unit 14 such as a machine direction finder, which is a device commercially available from vendors such as Marshall and Williams Company of Providence, Rhode Island. The apparatus 144 has a plurality of draw rollers 146 that move progressively at faster speeds relative to the torque placed before it. These rollers 146 apply a quantity of tension and therefore progressively stretch the laminate 100 to a length stretched in the machine direction of the film which is the direction of displacement of the laminate 100 through the process as shown in Fig. 3. The drawing rollers 146 can be heated for better processing. Preferably, the unit 144 also includes the rollers (not shown) up and / or down from the stretching rollers 146 that can be used to preheat the laminate 100 prior to orientation and / or anneal (or cool) after stretching .

In the stretched length, a plurality of micropores are formed in the filled film of the laminate 100 the unfilled film remains free of holes in the laminate. Preferably, the stretched length is from about 160 to about 500%, more preferably d from about 200 to about 400% of the pressed length of the film before stretching. If desired, the laminate 100 is directed away from the apparatus 144 so that the tension is removed to allow the stretched sheet 100 to relax.

It may be desirable to attach the continuous film / filled film laminate 100 to one or more substrate support layers 130 as shown in Figure 3. This additional lamination of the multilayer film laminate 100 can improve the strength and therefore The durability of the laminated film. If desired, the film laminate 100 can be bonded to one or more support layers 130 to form a reinforced sheet 132. Referring again to Figure 3, conventional fibrous nonwoven fabric forming apparatus 148, t as a pair was used. of banks of spunbonded, to form the support layer 120. The long, essentially continuous fibers 150 s deposited on a forming wire 152 as a non-binding fabric 154 and the unbonded web 154 are then sent through a roller p of bond 156 for joining the fibers together and increasing the tear resistance of the resultant tea support layer 130. One or both of the rolls are often heated to aid in bonding. Typically, one of the rollers 156 also has a pattern such as to impart a discrete bond pattern with a bound surface area prescribed to fabric 130. The other roller is usually a smooth yunq roller but this roller can also be patterned if so you want Once the film laminate 100 has been stretched sufficiently and the support layer 130 has been formed, the d layers are put together and joined to each other using a roll pair or other means 158. As with the tie rolls 156, the rolls 158 can be heated. Also, at least one of the rollers can be patterned to create a discrete bond pattern with a prescribed surface area bound for the resulting laminate. Generally, the maximum junction surface area for a given area of surface on a side of the laminate 132 will exceed about 50 percent of the total surface area. There are a number of discrete union patterns which can be used. See, for example, Brock et al., United States Patent Number 4,041,203 which is incorporated herein by reference in its entirety. Once laminate 132 leaves the laminating rollers 158, it can be wound onto a roll 160 for further processing. Alternatively, the laminate 132 can continue in line for further processing or conversion.

Even though the support layers 120 and the film sheet 100 shown in Figure 3 were joined together through the thermal spot junction, other bonding media may be used. Suitable alternatives include, for example, adhesive bonding and the use of binders. In the adhesive unit, an adhesive such as a hot-melt adhesive applied between the film and the non-woven fiber material for binding the film and the non-woven together. The adhesive can be applied by, for example, spraying melt printing or melt blowing. Various types of adhesives are available, including those produced from amorphous olefins, ethylene vinyl acetate hot melts, and KRATON brand adhesives available from She Chemical Company of Houston, Texas and RextacMAR brand adhesives from Rexene of Odessa , Texas.

When the support layer or layers and the film laminate are bonded with glutinizing agents, the glutinizer can be incorporated into the film itself. The essential glutinizer serves to increase the adhesion between the layers of fiber and film. The multilayer film and fib laminate can subsequently be thermally bonded, when generally very little heat is required since glutinizing tends to increase the sensitivity to film pressure and a bonding may form somewhat like an adhesive bond. Examples of useful glutinizers include WingtackMARCA 95 available from Goodyear Tire & Rubber Company, Akron, Ohio, and EscorezMARCA 5300 available from Exxon Chemic Company, of Houston, Texas.

If a laminate with elasticity is desired, the direction of elasticity in the laminate can be tailored to the state of the film, for example, if it is relaxed stretched, during bonding with the support layer as well as physical property of the support layer material. For example, if the film is still stretched while it joins the nonwoven and the supporting layer is stretchable in the transverse direction of the machine ("CD"), then a laminate with both the CD stretch and in the machine direction can occur. If film is bonded to a non-extendable support layer in the transverse direction while it is in a stretched state then a lamination can be produced with a stretch only the machine direction.

The support layers 130 and 130a as shown in Figure 3 are fibrous non-woven fabrics. The manufacture such fibrous non-woven fabrics is known. Such fibrous woven fabrics can help the additional properties for the film laminate 100 such as a more cloth and soft feel. This is particularly advantageous when film laminate 100 is being used as a liquid barrier layer in such applications as outer coverings for absorbent articles for personal care as barrier materials for surgical and clean room hospital applications such as, for example, surgical covers, suits and other forms of clothing.

The backing layer in a laminate containing the film layer of the present invention can be bonded with narrow or non-tapered polypropylene yarn, bonded with crimped polypropylene yarn, bonded carded fabrics, meltblown or bonded fabrics. with spinning. A particularly advantageous support layer is a fibrous non-woven fabric. Such fabrics may be formed from a process number including, but not limited to, the processes of bonded, meltblown and carded and bonded cloth. The meltblown fibr are formed by extruding the melted thermoplastic material through a plurality of usually circular and thin capillary tubes such as melted filaments or yarn into a gas stream usually heated at high speed such as air, which attenuates the melted thermoplastic filament to reduce its diameters. Then, the meltblown fibers are carried by the gas stream usually heated at high speed and deposited on a collecting surface to form a meltblown and randomly dispersed fiber. The meltblowing process is well known and is described in various patents and publications including the Laboratory Report of Naval Research 4364"Manufacture of superfine organic fibers" from B.A. Wendt, E.L. Boone and D.D. Fluherty; Naval Research Laboratory Report 5265"An improved device for the formation of superfine thermoplastic fibers of KD Lawrence, RT Lucas, JA Young; United States of America Patent No. 3,676,242 issued on July 11, 1972 to Prentice, and U.S. Patent No. 3,849,241 issued to Buntin, others, on November 19, 1974. The foregoing references are incorporated herein by this mention in its entirety.

Spunbonded fibers are formed by extruding a thermoplastic material melted with filament from a plurality of thin, usually circular, capillary vessels in a spinner organ with the diameter of the extruded filaments then being rapidly reduced, for example, by pulling eductive or non-eductive fluid other well known splicing mechanisms. production of the non-woven fabrics bonded with yarn is illustrated in the patents of the United States of America, such as Appel et al., No. 4,340,563; 3,802,817 granted to Matsuki others; 3,692,618 issued to Dorschner and others; 3,338,992 3,341,394 granted to Kinney; 3,276,944 granted to Lev 3,502,538 granted to Peterson, 3,502,763 granted to Hartma 3,542,615 granted to Dobo and others and the Canadian patent 803,7 granted to Harmon. All the above references are incorporated herein by this mention in their entirety.

A plurality of support layers 130 can also be used. Examples of such materials may include, for example, the laminates bonded with spinning / blowing with fusions and the laminates for bonding with spinning / blowing with melting / bonding and spinning as taught in Brook et al., United States of America patent. No. 4,041,203 which is incorporated by reference in its entirety.

The carded and joined fabrics are made of short fibr which are usually purchased in bales. The pac is placed in a defibrator which separates the fibers. Then the fibers are sent through a comb or carding unit which also breaks and separates and aligns the short fibers in the machine direction to form a woven fabric. fibrous oriented in the direction of the machine. Once the fabric has been formed, it is then joined by one or more of the various joining methods. A bonding method is a powdery union where a powder adhesive is distributed through the fabric and then activated, usually by heating the fabric and the adhesive with hot air. Another bonding method is a pattern bond where the heated calender rolls or the ultrasonic bonding equipment is used for a fibers together, usually in a bonding pattern even when the fabric can be bonded across its entire surface if so it is desired. When the bicomponent short fibers are used, the air-binding equipment is especially advantageous for many applications.

The process shown in Figure 3 can also be used to create a laminate wherein the sopor layers 130, 130a are bonded to the opposite surfaces of the film sheet 100. The only modification for the previously described process is to feed from a supply roll 162 of a second fibrous non-woven fabric support layer 130a inside the rollers of the laminate 158 on the side of the film laminate 100 opposite that of the other fibrous nonwoven fabric support layer 130. One or both of The support layers can be formed directly in line, as is the support layer 130. Alternatively, the supply one or both support layers can be in the form of preformed roll 162 as is the support layer 130a. In either case, the second support layer 130a is fed into the lamination rollers 158 and laminated to the film laminate 100 in the same manner as the first support layer 130.

As previously stated, the laminate d of the breathable barrier film 100 and the breathable laminate 132 can be used in a wide variety of applications including absorbent articles for personal care such as diapers. , the underpants of learning, incontinence devices and the products for the hygiene of the woman ta as the sanitary napkins. An example article 200, in this case a diaper, is shown in Figure 4 of the drawings. Referring to Figure 4, most such personal care absorbent articles 200 include a liquid-permeable upper liner or leaf 202, an outer cover or lower blade 204 and an absorbent core 206 positioned between the content of the upper sheet 202 and the lower sheet 204. The articles 200 such as the diapers may also include some type of fastening means 208 such as the fastening tapes. adhesive or hook-type fasteners and mechanical curl to keep the garment in place on the user. The restraint system can contain the stretch material to form the "stretched ears" for better comfort.

The film laminate 100 by itself or other forms such as the multiple support layer / film laminate 132 can be used to form various parts of the article including but not limited to the stretched region 210, the upper blade and the lower blade 204. If The film or laminate will be used as the liner 202, more likely it will have to be perforated or otherwise made permeable to the liquid. When the film / nonwoven laminate is used as the outer cover 204, it is usually advantageous to place the nonwoven side facing away from the wearer. Furthermore, in such embodiments, it may be possible to use the non-woven part of the laminate as the curl part of the curl hook combination. The advantages and other features of the present invention are best illustrated by the following examples: EXAMPLES 1-7 (Elastomeric and Laminated Films) The following laminate and elastomeric film samples were made or obtained from the suppliers. The water vapor transmission rate for each film and laminate was measured using the procedure described below. L values of water vapor transmission rate given reflect average of three samples for each example.

Stretching of Samples The stretched samples (for example, examples 3 and 5) were made by stretching in the machine direction of the films. Each sample was cut around 8 inches wide and 17 inches long. The ends were attached to wooden poles (about 0.75 inches x 15 inches by 24 inches) using Scotch tape. Each sample was rolled around the poles a couple of times to reinforce d so that the distance between the poles with an extended film sample between them was about 11 inches. The poles were separated until the sample had stretched by about 400% (for example at around 500% of original length) and the sample remained in the extended state for 2 minutes. The sample was then allowed to retract before the water vapor transmission rate was measured.

Base Weight Measurement Three samples of each sample were tested for the base weight. A 3 inch diameter punch die was used to cut the individual samples of each example. The samples were heavy. Base weights were calculated for each sample by dividing the weight by area. The average pes base for the three samples was reported above for each example.

Measuring the Vapor Transmission Rate of Agu (Water Vapor Transmission Rate) The 3-inch diameter samples of the base-weight test were also used for the water vapor transmission test. Again, three samples of each example were tested, and the results are reported as average values. The water vapor transmission rate measured according to procedure E-96-80 ASTM. Each sample placed on a test cup of water vap transmission rate to which 100 cubic centimeters of water had been added from the tap. The cups of the water vap transmission rate with the samples were allowed to equilibrate at room temperature and then weighed. The cups of the water vapor transmission rate with the samples were placed in Lindberg forced air oven / Model Blue MO 1440 set at 38 ° and the time recorded. After a period of time, the cups with water vapor transmission rate samples were weighed again to determine the amount of water that had been transmitted from the cups through the samples in the period of time. The results were calculated in grams of water per 24 hours-m2.

Preparation of Laminates For examples 4 and 5, the Super 7 adhesive made by the 3M Industrial Tape and Specialties Division of St. Pau Minnesota was sprayed onto the filled film and the polyurethane film separately and uniformly. The two films were put together with the faces covered with adhesive touching each other. The adhesive was allowed to dry for at least 1 hour before any handling or testing of the laminates would take place.

For Example 7, a peg board with holes 0.25 inches in diameter spaced 1 inch in a square pattern was placed on top of the filled film and on top of the polyurethane film. The Super 77 adhesive was sprayed through the holes of the plug board on the two films (filled film and polyurethane film) separately. The films were removed from the board and joined one another from the adhesive face to the adhesive face. The adhesive was left dry for at least 1 hour before any handling or rolling test was carried out.

Discussion of Aqua Vapor Trans Tas Test Results (Examples 1-7) Stretching of the filled films and elastomeric laminates resulted in some improvement in water vapor transmission rates, but overall water vapor transmission rates were unsatisfactory compared to commercial Deerfield and Celgard controls. It is believed that the shrinkage of the elastomeric films and laminates after stretching causes any of the gaps formed during the stretching to close. This closing of the gaps limits the improvements for films and elastomeric laminates.

Hydrohead Test (Examples 1-7) The films and laminates of examples 1-7 s tested for hydrohead values. The liquid used for the test was a mixture of 70% isopropyl alcohol and 30% water, sold under the brand name Homebest® of Glendale Foods, Inc., of Hazelwood, Missouri. The hydrohead test equipment used was the Textest Model FX300 available from Schmid Corporation, of Spartanburg, South Carolina.

The test procedure was as follows. The test apparatus was filled with the alcohol solution. Cad sample was placed in the tester. The tester was calibrated according to the manufacturer's instructions. The test was started and the liquid pressure was increased to 20 millibarras. The samples were observed regarding the penetration of the liquid for at least 10 minutes under this pressure.

The results are as follows. For the movie Celgard (Example 6), the liquid penetrated to less than 20 millibar pressure and formed a large pond on the outer surface in 1 minute.

For the unstretched filled film (Example 2) no runoff was observed for at least 6 minutes. When the sample was initially exposed to the liquid pressure of 20 millibar, it stretched and formed a sun about 2 inches in height and 4.5 inches wide, 8 minutes small drops formed, and at 13 minutes small droplets covered about 15% of the exposed surface of the film, at a frequency of about 10 drops / square centimeter.

The filled and stretched film (Example 3 initially withstood the liquid pressure of 20 millibars) After 4 minutes, there were numerous small drops on the exposed surface of the film, at a frequency of about 50 drops / centimeter.2 In the film also a 2-inch-tall sun was formed in response to the liquid pressure At 6 minutes, the small droplets coalesced.After minutes, the droplets coalesced into streams which ran down the surface of the film dome.

For the stretched laminate (Example 5) there was a total resistance to the passage of the liquid. At 20 millibarras d liquid pressure there was no penetration of the liquid visible in the laminate after 10 minutes.

The polyurethane film used in the laminate was also tested by itself. At 20 millibars of liquid pressure, there was no visible liquid penetration after 1 minute, indicating that the polyurethane contributed substantially to the penetration resistance shown by the laminate.

EXAMPLES 8-11 Samples of the films and the laminate of Examples 1, 3, 5 and 6 were prepared as described above and retested for the water vapor transmission rate in a stretched condition (in the non-retracted position) for all the following examples (except example 11)The films and the laminates were stretched essentially as described above, they were held for 2 minutes in the stretched condition and allowed to retract. Unlike the procedure mentioned above, the films and laminates of Examples 8-10 were then re-stretched to about 270% of initial length and tested for the rate of water vapor transmission in the rested condition. The following results were achieved.

As shown, the film filled in the rested condition (example 9) had a water vapor transmission rate comparable to the Deerfield film control, much better than the same film without the retraction (Example 3). The laminate B had a lower water vapor transmission rate, due to the presence of the adhesive and the polyurethane layer. These examples support the hypothesis that the rate of water vapor transmission of the filled and stretched films will depend on the amount of reaction (which tends to close the gaps).

The basis weight of the samples in the stretched condition was measured by pulling a 2.25 inch diameter circle on each stretched sample. After the samples were removed from the water vapor transmission rate apparatus and allowed to retract, the surrounding region was cut and weighed. In this way, the weight of each stretched sample was determined.

Therefore, the film of the present invention had a water vapor transmission rate and elasticity which imparted a wide variety of functionalities including the water vapor permeability, the chemical and / or liquid vapor impermeability, and a stretch and notch. In addition, such films can be bonded to the support layers to form laminates.

Of course, it should be understood that a wide range of changes and modifications can be made to the incorporations described above. It is therefore intended that the foregoing description should illustrate rather than limit this invention and that it is the following claims, all including their equivalents, which define this invention.

Claims (27)

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

1. A multilayer film laminate comprising: a film layer filled and oriented including a polymeric resin and a filler in a filler amount of at least about 10% by volume d said polymeric resin, said filled film has a water vapor transmission value of less than about d 300 grams / m2-24 hours; At least one continuous film layer attached to said layer of filled film, said continuous film layer includes an elongated resin.

2. The laminate, as claimed in clause 1, characterized in that the amount of said filling is from about 25% to about 50% by volume d said polymer resin.

3. The laminate, as claimed in clause 1, characterized in that said polymeric resin is selected from elastomers, thermoplastic thermoplastic polymers, thermoplastics and combinations thereof.

4. The laminate, as claimed in clause 1, characterized in that said polymeric resin selected from urethane elastomers, silicone elastomers, butylene-isoprene elastomers, isoprene, polyacrylate elastomers, neoprene, nitrile elastomers, polybutadiene elastomers, propylene elastomers ethylene, fluorocarbon elastomers, phosphonitrile elastomers, chlorinated polystyrene elastomers, fluorosilicon elastomers, polysulfide elastomers, polyethylene chlorosulfonated elastomers, hepiclorohydrin elastomers, styrene-butadiene elastomers, olefinics, styrenics, polyester urethane, polyether-urethanes, caproester-urethanes, elastomer thermoplastic copolyether-ester.

5. The laminate, as claimed in clause 1, characterized in that said first elastomeric resin is selected from urethane elastomers of silicone elastomers, butylene-isoprene isoprene elastomers, polyacrylate elastomers, neoprene, nitrile elastomers, polybutadiene elastomers, elastomers of propylene ethylene, fluorocarbon elastomers, phosphonitrile elastomers, chlorinated polystyrene elastomers, fluorosilicone elastomers, polysulfide elastomers, chlorosulfonated polyethylene elastomers, hepiclorohydrin elastomers, styrene-butadiene elastomers, combinations thereof.

6. The laminate, as claimed in clause 1, characterized in that said elastic filled film and has a first permanent stretching feature.

7. The laminate, as claimed in clause 6, characterized in that said film layer continues to have a second permanent settled stretch that is less than said first permanent settlement.

8. The laminate, as claimed in clause 1, characterized in that it comprises at least one support ca.

9. The laminate, as claimed in clause 8, characterized in that the support layer is joined to said continuous film layer.

10. The laminate, as claimed in clause 8, characterized in that said first support layer is attached to said layer of filled film and a second support layer is attached to said layer of continuous film.

11. The laminate, as claimed in clause 8, characterized in that the support layer is a fibrous non-woven tea.

12. A medical garment comprising: a layer of filled film including a polymeric resin and a filler in a fill amount of at least about 10% by volume of said polymeric resin, said filled film having a water vapor transmission value of at least around 4 g / m2-24 hours; at least one continuous film layer joined to said filled film layer, said continuous film layer includes a first elastomeric resin, said continuous film layer being permeable to water vapor and impermeab to the odor causing molecules; and at least one support layer.

13. The medical garment, as claimed in clause 12, characterized in that a first layer of sopor is attached to said layer of filled film and a second support layer is attached to said layer of continuous film.

14. An absorbent personal care article comprising a liquid pervious upper sheet, a lower sheet with an absorbent core positioned therebetween, at least one of said inner sheet and said upper sheet includes the laminate as claimed in FIG. clause 1

15. The article, as claimed in clause 14, characterized in that it also comprises a peripherally disposed stretch region d with respect to said upper leaf and said lower sheet, at least one of the stretch region, said back sheet and said sheet above include said laminate.

16. The article, as claimed in clause 14, characterized in that said article is a diaper.

17. The article, as claimed in clause 14, characterized in that said article is a learning underpants.

18. The article, as claimed in clause 14, characterized in that said article is a sanitary towel.

19. The article, as claimed in clause 14, characterized in that said article is an incontinence device.

20. The article, as claimed in clause 14, characterized in that said article is a bandage.

21. A process for forming a filled film / continuous film laminate comprising: providing a filled film layer which includes a polymeric resin and a filler in a filler amount of at least about 10% by volume d of said polymeric resin; joining at least one layer of continuous film bonded to said layer of filled film to form a laminate, said layer of continuous film includes a first elastomeric resin, said layer of continuous film is permeable to water vapor and impermeable to the molecules that cause the smell; stretching said laminate to result in a stretched laminate wherein said filled film has a water vapor transmission value of at least d about 450 g / m2-24 hours; allowing said stretched laminate to relax to form a continuous film / microporous film laminate.

22. The process, as claimed in clause 21, characterized in that said filled film is bonded to said continuous film with an adhesive.

23. The process, as claimed in clause 21, characterized in that said filled film is thermally bonded to said continuous film.

24. The process, as claimed in clause 21, characterized in that it comprises the step of joining said stretched laminate to a non-woven fabric.

25. The process, as claimed in clause 21, characterized in that it further comprises the step d joining said laminate to a non-woven fabric after allowing the relaxed laminate to relax.

26. The process, as claimed in clause 21, characterized in that said continuous film and said filled film are knitted together.

27. The process, as claimed in clause 21, characterized in that said continuous film and said filled film are continuously joined together. SUMMARIZES A multilayer film lamination with breathability that includes a microporous filled film bonded to a continuous film. A backing layer such as a fibrous web can adhere to the film laminate on one or both surfaces.