MXPA06005197A - Biodegradable and breathable polymer film - Google Patents

Abstract

A composition for a film which is both biodegradable and breathable and films prepared from the composition and then stretched are disclosed. The film comprises from about 30%to about 70%by weight of a biodegradable copolyester and from 70%to about 30%by weight of a filler, and the film is stretched in either a monoaxial or biaxial direction to increase void formation and achieve a water vapor transmission rate (WVTR) of at least 800 grams per square meter per 24 hours, and more particularly a WVTR of greater than 1900 grams per square meter per 24 hours. The copolyester is typically a copolyester of aliphatic/aromatic acids and the filler is typically calcium carbonate. The film is suitable for use in disposable breathable products such as personal care products, absorbent products, health care products, bandages and medical fabrics.

Description

BIODEGRADABLE POLYMER FILM WITH BREATHING CAPACITY COUNTRYSIDE The present invention is generally related to biodegradable polymer film compositions and more particularly to breathable biodegradable polymer film compositions.

BACKGROUND OF THE INVENTION Polymer films are useful in making a variety of disposable articles because they are relatively inexpensive to manufacture, and can be made to be strong, durable, flexible, soft, and a barrier for aqueous liquids such as water. Examples of such disposable products or articles include, but are not limited to, health care and medical products such as surgical covers, gowns and bandages, protective work garments such as covers all and lab coats, and absorbent articles for personal care of adults, children, and infants such as diapers, underpants for learning, and disposable swimsuits, pads, and garments for incontinence, sanitary napkins, cleaning cloths and the like. Other uses for polymeric film materials include geotextiles. It is often highly desirable for the polymer films used in such product applications to be both breathable and liquid impervious.

It is known that breathable films can be prepared by mixing an incompatible inorganic or organic filler with a polyolefin-based resin, which is then melted, formed into film and stretched. These films are mainly used as barriers to the liquid in disposable personal care products, which are discarded immediately after use. However, breathable films made of polyolefin-based resin can not be degraded in the natural environment.

Because there is a demand that increases for the incorporation of more degradable and / or recyclable components in disposable products, and the design of the products that can be discarded by other means instead of the incorporation in facilities for the disposal of solid waste such as of the land filling. As such, there is a need for new materials for disposable absorbent products that generally retain their integrity and resistance during use, but after such use, they are more efficiently discarded. For example, the disposable absorbent product can be easily and efficiently discarded by compost. Alternatively, the disposable absorbent product can be easily and efficiently discarded to a liquid drainage system where the disposable absorbent product is capable of being degraded.

Although it is possible to improve the ability to breathe and the biodegradability of the polymer films separately, improving the biodegradability of the polymer films, without decreasing the breathing capacity of the films, is difficult. For example, biodegradable films derived from copolyesters are known in the art. These films tend to be very flexible and ductile, with a longer elongation than breaking. However, due to the extremely ductile nature of these compounds, the pore formation in such films is much less pronounced than in comparable polyethylene-based compositions, resulting in a low water vapor transmission rate (WVTR). of 400 grams per square meter per 24 hours in stretched films. This does not compare favorably with the breathability values of up to 20,000 water vapor transmission rate which can be achieved in stretch films based on polyethylene compositions. These copolyester films are therefore not suitable for personal care products. breathe, but are rather appropriate for use as waste bags, in packaging applications and the like.

Therefore, even when biodegradable films are known, these films fail to provide the same or substantially similar properties of high water vapor permeability as the currently used breathable (but not biodegradable) polyethylene films.

Therefore, there remains a need for a composition which can be used to make a biodegradable film which also has the ability to breathe, for use in making articles for single use or disposable manufacturing.

SYNTHESIS OF THE INVENTION The present invention provides a breathable, biodegradable film and a process for manufacturing a breathable, biodegradable film. The film can comprise from about 30% to about 70% by weight of a biodegradable copolyester and about 70% up to about 30% by weight of a filler, where the film is stretched in at least one monoaxial direction to achieve a water vapor transmission rate of at least about 800 grams per square meter per 24 hours. In another embodiment, the film has from about 40% to about 55% by weight of copolyester and from about 60% to about 40% by weight of filler. In yet another embodiment, the film may have a water vapor transmission rate of at least about 1900 grams per square meter per 24 hours.

The biodegradable, breathable film may include copolyesters for aliphatic / aromatic acids such as copolyester and calcium carbonate as the filler.

In certain embodiments, the filler may have an average particle size in the range of about 0.1 to about 7 microns, and in other embodiments the filler may have an average particle size in the range of about 0.8 to about 2.6. micrometers The breathable, biodegradable film may additionally include a compatibilizer, and the compatibilizer may be such as a fatty acid, an unsaturated fatty acid, an amide thereof, a silane coupling agent, an alkyl titanate, and so on The film can be stretched in a mono axial direction to obtain a stretch ratio of from about less than Ix to about 5x in the machine direction (MD), for example about 200% or 250%. The film can optionally also be stretched in a biaxial direction so as to obtain a stretching ratio which is desirably in the range from less than Ix by lx to about 3x by 3x in the cross machine direction (CD).

The process for manufacturing the breathable and biodegradable film includes the steps of mixing with cast iron from about 30% to about 70% by weight of a biodegradable copolyester and from about 70% to about 30% by weight of a filler to form a resin, form the film resin to form a film, and then stretch the film in at least a monoaxial direction to thereby achieve a water vapor transmission rate of at least 800 grams per square meter per 24 hours. In embodiments, the film may desirably be biaxially stretched.

Additionally supplied are the laminates and the disposable articles of manufacture comprising the breathable, biodegradable film, such items as for example medical products, garments protective and absorbent articles for personal care.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partially cutaway view illustration of a laminate material comprising the biodegradable and breathable films of the invention.

Figure 2 is a perspective view of a disposable diaper comprising the biodegradable and breathable film of the invention.

DEFINITIONS As used herein and in the claims, the term "comprising" is inclusive or open ended and does not exclude additional non-recited elements, compositional components, or method steps. Therefore, the term "comprising" encompasses the more restrictive terms "consisting essentially of" and "consisting of".

As used herein, "biodegradable" has the meaning of representing that a material degrades from exposure to air and / or water or from the action of naturally occurring microorganisms such as bacteria, fungi and algae.

As used herein, the term "ability to breathe" refers to the rate of water vapor transmission (WVTR) of an area of the film. The ability to breathe is measured grams of water per square meter per day.

As used herein, the term "breathing" refers to a film that has a water vapor transmission rate of at least 800 grams of water per square meter per day.

As used herein, the term "copolymer" generally includes but is not limited to alternating, random, grafted and block copolymers and mixtures and modifications thereof.

As used herein, the term "filler" means that it includes particles and other forms of materials which can be added to the film mixture and which will not chemically interfere or adversely affect the extruded film but which are capable of uniformly dispersing. through the movie. Fillers known in the art include inorganic particulate materials such as, for example, talc, calcium carbonate, barium carbonate, magnesium carbonate, magnesium sulfate, titanium dioxide, mica, clays, kaolin, diatomaceous earth and the like, and organic particle materials such as powdered polymers such as TEFLON and KEVLAR, and wood and other cellulose powders.

As used herein, the term "personal care product" means personal hygiene-oriented articles such as cleansing wipes, diapers, underpants for learning, absorbent undergarments, adult incontinence products, the products for the hygiene of women, and so on.

DETAILED DESCRIPTION OF THE INVENTION The invention provides a composition that includes a biodegradable copolyester and a filler, the composition is suitable for making biodegradable films which are also breathable when stretched in either a monoaxial or biaxial direction. Such films have good biodegradable and mechanical properties compared to films made solely from the copolyester.

Other additives and ingredients can be added to the film layer provided they do not seriously interfere with the ability of the film to be breathable or biodegradable. For example, a compatibilizer such as a fatty acid (for example stearic acid, oleic acid or behenic acid), the unsaturated fatty acid, the amide thereof (for example erucamide or oleamide), the silane coupling compound, the titanate of alkyl, and so on can be added to improve the mechanical properties of the film. Dyes, reinforcers and other types of fillers can also be added.

Suitable copolyesters are those that have good physical properties and biodegradability. Such copolyesters are described in European Patent No. EP 1 106 640 and in European Patent No. EP 1 108 737, both issued to Chong et al., In which copolyesters are prepared by the reaction of (i) 0.1% by weight up to 30% by weight of an oligomer similar to an aromatic-aliphatic prepolymer having an average molecular weight of from 300 to 30,000; (ii) 40% by weight up to 71% by weight of one or more alicyclic dicarboxylic acid anhydrides; and (iii) 29% by weight up to 60% by weight of one or more alicyclic or aliphatic glycerols. Specific examples of aliphatic / aromatic copolyesters are ENPOL® G8060 and IRE® 8000 from Ire Chemical Ltd. of Seoul, South Korea, and EASTAR® from Eastman Chemical of Kingsport, Tennessee, United States of America.

Generally the filler can be an inorganic filler in the form of a particle and is usually another to have something of a hysterical shape with an average particle size in the range of about 0.1 to about 7 microns, and more particularly in the range of about 0.5 to about 2.6 microns. Examples of inorganic fillers include calcium carbonate, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, zinc oxide, magnesium oxide, calcium oxide , titanium oxide, barium oxide, aluminum oxide, aluminum hydroxide, hydroxyapatite, silica, mica, talc, kaolin, clay, glass powder, asbestos powder, zeolite and acid clay. Particularly desired inorganic fillers are calcium carbonate, magnesium oxide, barium sulfate, silica and acid clay. Calcium carbonate can be obtained from English China Clay (marketed as Imerys) from Roswell, Georgia, United States of America, or from Omya from Florence, Vermont, United States of America.

Generally, on a dry weight basis, based on the total weight of the film, the composition may include from about 30% to about 70% by weight of copolyester and from about 70% to about 30% by weight of filler More desirably, the composition may include from about 40% to about 55% by weight of copolyester and from about 60% to about 40% by weight of filler. For example, the copolyester and the Filler may be present in a proportion of 50:50 by weight.

In order to provide a capacity for breathing a report by the water vapor transmission rate (WVTR) of the film, the filler should be substantially evenly dispersed throughout the composition and, consequently, through the film itself.

The copolyester and filler can be mixed in appropriate proportions given the ranges previously delineated and then compounded and extruded into a film layer using any of a variety of processes to produce film known to those of ordinary skill in the art, including melted and blown. The composition can alternatively be made pellet before the film forming step, instead of the film being directly obtained from the extruder. The extrusion temperature can desirably be in the range of from about 180 ° C to about 270 ° C, and more desirably in the range of from about 200 ° C to about 250 ° C, for example, about 220 ° C.

The film can then be stretched in a monoaxial direction to obtain a stretch ratio in less than about lx to about 5x in the machine direction (MD), for example about 200% or 250%, as shown in FIG. more fully details in the patents of the United States of America Nos. 5,695,868 and 5,855,999 both granted to McCormack, incorporated herein by reference in their totalities, in order to render it porous. The film optionally may also be stretched in a biaxial direction (e.g. in both longitudinal and lateral directions) to thereby obtain a stretch ratio which desirably is in the range of less than about less than about lx 'per lx to about 3x by 3x in the cross machine direction (CD), for example, about 64% by 64%. The stretching temperature can be in the range of from 20 ° C to around 100 ° C, for example, 22 ° C, 30 ° C or 70 ° C.

By stretching the film, the vacuum formation in the film is improved and therefore the film is made more porous and able to breathe. The biaxial stretching of the film produces even greater vacuum formation and therefore an improved breathability of the film.

For the purposes of the present invention, a film is "breathable" if it has a water vapor transmission rate of at least 800 grams per square meter per 24 hours calculated using the MOCON® test method, which it is described in more detail below. The water vapor transmission rate of the film of this invention is within the range of about 800 grams up to about 15,000 grams per square meter per 24 hours, and more desirably within the range of 1,900 to 15,000 grams per square meter per 24 hours, and it is even more desirable at least about 2,500 grams per square meter per 24.

Generally, once the film is formed, it may have a weight per unit area of less than about 100 grams per square meter, and after stretching and thinning its weight per unit area or basis weight may desirably be less. of around 35 grams per square meter. In some embodiments, the basis weight may desirably be less than about 25 grams per square meter, and more desirably less than about 20 grams per square meter, and still more desirably less than about 17 grams per square meter.

The thickness of the film may differ depending on its uses and is generally in the range of from about 10 to about 300 microns.

The film has an elongation at break of at least about 10% and more desirably at least about 200%.

As a result, while you do not want to be limited to specific uses as specified here.

The film of the present invention has particular use as a reinforcing material for personal care articles, absorbent products, health care products, medical fabrics and the like.

MOCON® Water Vapor Transmission Rate Test: An appropriate technique for determining the value of the water vapor transmission rate (WVTR) of a material is the test procedure standardized by INDA (Association of the Non-Woven Fabrics Industry), number IST- 70.4-99, entitled "STANDARDIZED TEST METHOD FOR THE RATE OF TRANSMISSION OF WATER STEAM THROUGH A FILM OF PLASTIC AND NON-WOVEN USING A GUARD MOVIE AND A STEAM PRESSURE SENSOR "which is incorporated by reference herein The INDA procedure provides for the determination of the water vapor transmission rate, the permanence of the film to steam of water and, for the coefficient of water vapor permeability, of homogeneous materials.

The INDA test method is well known and can not be disclosed in detail here. However, the test procedure is summarized as follows. A dry chamber is separated from a wet chamber of known temperature and humidity by a permanent guard film and the sample material to be tested. The purpose of the guard film is to define a separation of air definitive and to silence or stop the air in the air separation while the separation of air is characterized. The dry chamber, the guard film, and the humid chamber form a diffusion cell in which the test film is sealed and. The sample retainer is known as the PERMATRAN-W® model 100K manufactured by Modern Controls, Inc. (MOCON®) of Minneapolis, Minnesota, United States of America. A first test is made of the water vapor transmission rate of the guard film and the air separation between the evaporator set that generates 100% relative humidity. The water vapor is diffused through the separation of air and the guard film and then mixed with a flow of dry gas which is proportional to the concentration of water vapor. The electrical signal is directed to a computer for processing. The computer calculates the transmission rate of air separation and guard film and stores the value for later use.

The transmission rate of the guard film and the air separation is stored in the computer as CalC. The sample material is then sealed in the test cell. Once again, the water vapor is diffused through the air separation to the guard film and the test material and then mixed with a flow of dry gas that sweeps the test material. Also, once again, this mixture is transported to the vapor sensor. The computer then calculates the transmission rate of the combination of the separation of air, of the protective film and of the test material.

This information is then used to calculate the transmission rate at which moisture is transmitted through the test material according to the equation: TR test material - J test material, protective film, air separation - TR "1 protective film, air separation The calculation of the water value transmission rate uses the formula: WVTR = Fpsat (T) RH / Apsat (T) (1-RH) where : F = the water vapor flow in cubic centimeters / minute, Psat (T) = the density of water in saturated air at temperature T, RH = the relative humidity in specific places in the cell, A = the cross-sectional area of the cell, and Psat (T) = vapor pressure of water vapor saturation at temperature T.

The invention will now be described in greater detail by way of the following non-limiting examples, which are designed to illustrate particular aspects of the invention and teach one with ordinary skill in the art how to carry out the invention.

EXAMPLES Example 1 A biodegradable copolyester polymer resin, ENPOL® G8060 was obtained from Ire Chemical Limited of South Korea. ENPOL® G8060 is a biodegradable aliphatic / aromatic copolyester completely having a melting point of 127 ° C, a melt index of 1.4-5 grams per 10 minutes at 190 ° C and 2160 grams of filler.

Two biodegradable films (A and B, respectively) were prepared and evaluated to determine the water vapor transmission rate (WVTR) of each film. Film A was prepared using carbonate calcium obtained from English China Clay, and film B was prepared using a calcium carbonate obtained from Omya (OMYACARB® 2SST).

The copolyester was combined with the calcium carbonate in a 50:50 weight percent ratio, using a twin screw extruder. The composition was then extruded with melt in films about 20 micrometers thick. The extrusion temperature was in the range of from about 180 to about 270 ° C, and more desirably in the range from about 200 to about 250 ° C. (a) The first samples of each of the films A and B (the samples Al and Bl, respectively) were placed in an orientation unit in the direction of the conventional machine (MDO), such as that manufactured by The Marshall and Williams Company, where these were stretched in the machine direction (MD) as described in U.S. Patent Nos. 5,695,868 and ,855,999. granted to McCormack, so as to obtain a stretch percentage of 250%. The stretching was carried out in a furnace at a temperature of 70 ° C. After stretching, the settling with heat was carried out in order to improve the stability of shape of the pores.

The stretch ratio was defined as: Percent stretch = (length of final film - original length) / original length x 100. (b) Second samples of each of the films A and B (samples A2 and B2, respectively) were placed in the same direction unit of the machine and were stretched in the MD direction to obtain a stretch percentage of 200% at 30 ° C.

The water vapor transmission rate of the films was measured according to the MOCON® method described above. The results are shown in Table 1.

TABLE 1. Monoaxial stretch of film samples Example 2 Samples of each of films A and B prepared in Example 1 (samples A3 and B3, respectively) were subjected to biaxial stretching. The films were fed through a set of rolls of interspersed slots at room temperature (around 22 ° C). The hooking of the rollers created the direction transversal to the machine (CD), whose extension was measured by the length gain in the transverse direction. The stretched films were then rotated by approximately 90 ° and again fed through the slot rollers to carry out a second extension or directional stretch so that the films were stretched or stretched biaxially. After stretching, the settling with heat was carried out in order to improve the stability of shape of the pores.

The stretch ratio was defined by the percentage of length gain in both directions.

The measurements of water vapor transmission rate were again determined according to the MOCON® method described above, and the results are shown in Table 2.

TABLE 2. Biaxial stretch of film samples The above examples indicate that a biodegradable film can be produced having a good water vapor transmission rate value and therefore a good ability to breathe. Therefore, the ability to breathe of the films is markedly improved when the films are stretched biaxially. Such breathable and biodegradable films are very useful for use in disposable or single use articles and products where a fluid impervious barrier is required but the barrier is also desirably stretchable. Examples of such products include, but are not limited to, health care and medical products such as surgical covers, gowns and dressings, protective workwear such as lab coats and lab coats, and absorbent articles. for infant, child and adult personal care such as diapers, training briefs, disposable swimwear, incontinence garments and pads, sanitary napkins, cleansing wipes and the like. Other uses for such materials Biodegradable and breathable polymer film can include geotextiles. Although not described in detail herein, several potential processing and / or finishing steps known in the art such as opening, slit-cutting, further stretching, processing or lamination of breathable and biodegradable polymeric film materials. with other films or layers of non-woven fabric can be carried out without departing from the spirit and scope of the invention.

Examples of the lamination of the breathable and biodegradable polymeric film materials with other nonwoven films or layers include laminated materials having two or more layers, such as the example bi-layer laminate shown in Figure 1. Fabrics or non-woven fabrics have been formed from many processes such as, for example, meltblowing processes, spinning processes, air laying processes, and carded fabric processes. Figure 1 demonstrates a laminated material which is a laminate of the polymeric film capable of breathing and biodegradable with a nonwoven fabric layer such as, for example, a layer of spunbonded cloth bonded to the film. Non-woven fabrics bonded with spinning are well known in the art and will not be described in detail here. Briefly, spun-bonded refers to a non-woven fiber or filament material of small diameter filaments that are formed by extruding a melted thermoplastic polymer as filaments from a plurality of capillaries of a spinning organ. The extruded filaments are cooled while being pulled by an eductive pulling mechanism or other well-known mechanism. The pulled filaments are deposited or placed on a forming surface in a generally random fashion to form a loose-wrapped tangled web., and then the filament weave is subjected to a joining process to impart physical integrity and dimensional stability. The production of the yarn-bonded fabrics is described, for example, in US Pat. Nos. 4,340,563 issued to Appel et al.; 3,692,618 issued to Dorschner and others; and 3,802,817 issued to Matsuki and others, all of which are hereby incorporated by reference in their entirety. Typically, yarn-bonded fibers or filaments have a weight-per-unit length in excess of about 1 denier and up to about 6 denier or greater, even though both finer and heavier yarn-bonded filaments can be produced. In terms of filament diameter, the spunbonded filaments often have an average diameter of more than 7 microns, and more particularly of between about 10 and about 25 microns, and up to about 30 microns or more.

Figure 1 is a schematic only, merely illustrative of one of the types of laminates attempted.

Generally, such multi-layer non-woven film laminates have a basis weight of from about 3 to about 400 grams per square meter, more particularly from about 15 grams per square meter to about 150 grams per square meter . As shown in the bilayer laminate of FIG. 1, it is generally designated 10 and comprises a biodegradable, breathable polymeric film layer 30 to which a layer of non-woven fabric 20 is attached. known to a person skilled in the art, such laminates can be laminated together by, for example, adhesive bonding, ultrasonic bonding, or thermal bonding such as a thermal spot or "spot" bond. In Figure 1, point junctions 40 are further shown as they can be made by a thermal point joining process, joining or matching two laminate materials together at spaced and spaced locations in a dot pattern. Adhesive bonding is also known in the art and it can be particularly advantageous where the layers of laminate component to be joined together do not bond thermally well, such as where the components have disparate melting points or disparate softening temperatures. In addition, it should be noted that breathable and biodegradable films can also be laminated as part of a tri-laminate material such as a nonwoven / film / non-woven laminate. Such a tri-laminate material may be particularly desirable in applications such as for example in disposable medical fabrics, where it is useful to have one more layer of cloth type on both sides of the film layer with breathing barrier.

As mentioned, the breathable and biodegradable polymeric film materials of the invention are highly suitable for use in absorbent articles for personal care. Returning to Figure 2 there is shown an example personal care article such as diaper 60. Diaper 60, as is typical for most personal care absorbent articles, includes a body-permeable body side liner. liquid 64, for example an inner side or facing the body, and an outer cover impervious to liquid 62, for example an outer side or not facing the body. Various woven or non-woven fabrics may be used for the side-to-body liner 64 such as a non-woven fabric bonded with spinning of polyolefin fibers or a carded and bonded fabric of natural and / or synthetic fibers. The liner 64 can also be beneficially a spunbonded fabric or a woven and carded material comprising the multi-component fibers of the invention. The outer cover 62 is formed of a liquid barrier material such as for example the biodegradable and breathable polymeric film materials of the invention. Such outer cover of polymer film material can be etched and / or matte finished to provide a more aesthetically pleasing appearance or it can be a laminate formed of the breathable and biodegradable film and of a woven or non-woven material, as described above, to provide a more aesthetically pleasing and firm feel or more "cloth-type" characteristics.

Positioned between the liner 64 and the cover 62 is an absorbent core 66 formed, for example, of a blend of hydrophilic cellulosic wood pulp fluff and highly absorbent gelation particles (for example a super absorbent material). The absorbent core 66 may further comprise thermoplastic binder fibers as is known in the art. The diaper 60 may also include the optional containment flaps 72 made or attached to the side-to-body liner 64. Suitable constructions and arrangements for such containment fins are described, for example, in U.S. Patent No. 4,704,116 issued to Enloe, and incorporated herein by reference in its entirety. Still further, the diaper 60 may optionally include additional elements known to those skilled in the art including but not limited to elasticated leg cuffs, elastic waistband and others. To secure the diaper 60 around the wearer, the diaper will have some type of fastening means attached thereto. As shown in Figure 2, the fastening means are a. hook and loop fastening system including hook elements 74 attached to the inner and / or outer surface of the outer cover 62 in the region of back waistband of the diaper 60 and one or more elements or patches of locks 76 fastened to the outer surface of the outer cover 62 in the front waist region of the diaper 60. The loop material for the patch of curls 76 can be a material of woven, nonwoven or knitted curls and can be secured to the outer cover 62 of the diaper 60 by known fastening means, including but not limited to the adhesives, to the thermal bond, the ultrasonic joint, or to a combination of such means . As an alternate embodiment, a nonwoven web material may cover all or substantially all of the outer surface of the outer cover 62.

Even though several patents and other reference materials have been incorporated herein, to the extent that there is some inconsistency between the incorporated material and that of the written description, the written description will control. Furthermore, even though the invention has been described in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various modifications, alterations and other changes to the invention can be made without departing from the spirit and scope of the invention. present invention. Therefore, it is intended that the claims cover or cover all those modifications, alterations and / or changes.

Claims (20)

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

1. A breathable and biodegradable film comprising: about 30% to about 70% by weight of a biodegradable copolyester; Y around 70% to around 30% by weight of a filling; wherein the film is stretched in at least one monoaxial direction to achieve a water vapor transmission rate of at least about 800 grams per square meter per 24 hours.

2. The film as claimed in clause 1, characterized in that it is stretched in a monoaxial direction so as to obtain a stretch ratio in the machine direction from about 2x to about 5x.

3. The film as claimed in clause 1, characterized in that it is biaxially stretched.

. The film as claimed in clause 3, characterized in that it is stretched as for obtain a stretch ratio in the cross-machine direction from about lx by lx to about 3x by 3x.

5. The film as claimed in clause 1, characterized in that the biodegradable copolyester comprises a copolyester of aliphatic / aromatic acids.

6. The film as claimed in clause 1, characterized in that the filling is calcium carbonate.

7. The film as claimed in clause 1, characterized in that the filler is a particulate material having an average particle size in the range of from about 0.1 to about 7 microns.

8. The film as claimed in clause 1, characterized in that the filler is a particulate material having an average particle size in the range of from about 0.8 to about 2.6 microns.

9. The film as claimed in clause 1, further characterized in that it comprises a compatibilizer.

10. The film as claimed in clause 9, characterized in that the compatibilizer is selected from the group consisting of fatty acids, fatty acid amides, silane compounds and alkyl titanates.

11. The film as claimed in clause 9, characterized in that the compatibilizer comprises from about 0.02% by weight to about 2% by weight of the film.

12. The film as claimed in clause 1, characterized in that it comprises from about 40% by weight to about 55% by weight of the biodegradable copolyester and from about 45% to about 60% by weight of the filler.

13. The film as claimed in clause 1, characterized in that it has a water vapor transmission rate of more than about 1,900 grams per square meter per 24 hours.

14. The film as claimed in clause 12, further characterized in that it comprises at least one additional layer attached thereto.

15. A disposable article manufactured comprising a film as claimed in clause 1.

16. The disposable article as claimed in clause 15, characterized in that it is selected from the group consisting of medical products, protective garments and absorbent articles for personal care.

17. A process for manufacturing a biodegradable and breathable film comprises the steps of: mixing with melting from about 30% to about 70% by weight of a biodegradable copolyester and from about 70% to about 30% by weight of a filler to form a resin; forming the resin into film to form a film; Y stretch the film in at least one monoaxial direction so as to achieve a water vapor transmission rate of at least 800 grams per square meter per 24 hours.

18. The process as claimed in clause 17, further characterized in that it includes the step of stretching the film in a biaxial direction.

19. The process as claimed in clause 17, characterized in that the inorganic filler is calcium carbonate.

20. The process as claimed in clause 17, characterized in that the biodegradable copolyester comprises a copolyester of aliphatic / aromatic acids. SUMMARY A composition for a film which is both biodegradable and capable of breathing and the films prepared from the composition and which are then stretched are described. The film comprises from about 30% to about 70% by weight of the biodegradable copolyester and from 70% to about 30% by weight of a filler, and the film is stretched in either a monoaxial or biaxial direction to increase the formation of holes and achieve a water vapor transmission rate (WVTR) of at least 800 grams per square meter per 24 hours, and more particularly a water vapor transmission rate of more than 1,900 grams per square meter for 24 hours. The copolyester is typically a copolyester of aliphatic / aromatic acids and the filler is typically calcium carbonate. The film is suitable for use in disposable breathable products such as personal care products, absorbent products, health care products, bandages and medical fabrics.