MXPA01000286A - Water soluble polyethylene oxide films - Google Patents

Abstract

The invention relates to blends of a polyethylene oxide (PEO) resin and a latex emulsion. The blends are formed by mixing or coating a PEO powder resin with a latex emulsion and melt blending the powder. The blends have improved processibility and toughness which are beneficial in the manufacture of PEO-based films and fibers. The films composed of the PEO/latex blend have improved toughness, breathability, and tear resistance and are useful for the manufacture of disposable, flushable medical and personal care products, such as diapers, tampons, feminine napkins, and bladder control pads.

Description

WATER SOLUBLE P2 DLY2THENUM OXIDE FILMS FIELD OF THE INVENTION The present invention relates generally to polymeric films, to the processes for their manufacture, and to their use in disposable medical and personal care products with water discharge. More specifically, the invention relates to the modification and processing of polyethylene oxide (PEO) resins to make films for the production of such water discharge products which have the advantages of improved flexibility, softness and tear resistance. .

BACKGROUND OF THE INVENTION Disposable personal care products, such as panty liners, diapers and tampons, are of great comfort, as are disposable medical care products, such as covers, suits, covers for the head, and masks for the face. These products provide the benefit and convenience of a one-time sanitary use. However, the disposition or disposal of many of these products is a concern due to the limited landfill space. The incineration of such products is undesirable due to the increasing concerns about air quality and due to the costs and the difficulty associated with separating these products from other disposable items that can not be incinerated. Consequently, there is a need for disposable products which can be quickly and conveniently discarded without being thrown away or incinerated.

It has been proposed to dispose of such products in municipal and private sewerage systems. Ideally, the products will be degradable in conventional sewerage systems. Products suitable for disposal in sewage systems which can be discarded by discharging water into conventional toilets and which disperse or disintegrate in water are called disposable. with water discharge. "Disposal in this form is simple, convenient and sanitary.

Personal care and medical products must have sufficient strength to maintain their integrity under the environmental conditions in which they will be used. These must be able to withstand the high temperature and humidity conditions encountered during use and storage and still lose their integrity with contact with water in the toilet. Therefore, a Water-disintegrable material which is capable of thermal processing in a thin film having a mechanical integrity.

Currently, thin films are typically made of water insoluble polymers or polymer blends. Frequently used polymers include amorphous polymers, epoxy resins and semicrystalline polymers. 5 Examples of the amorphous polymers are polystyrene (PS), styrene-acrylonitrile copolymers, polycarbonate, and poly (vinyl chloride) (PVC). Examples of semicrystalline polymers are polyethylene (PE), polyamide (PA), polybutadiene (PB), and polypropylene (PP). The polymers most commonly used are polypropylene and polyethylene.

Thin films composed of these polymers are formed by melt blowing or melt extrusion processes. The conventional film extrusion involves mixing the commercially available pellets of the desired polymers at increased temperatures, followed by extruding the mixture and a single screw extruder through a slot die to form a film. The film is then cooled by passing it through a series of cooled rollers. Films made in this form of such water-insoluble polymers are not suitable for use in "disposable water discharge" personal care and medical care products because they do not possess the desired characteristics, for example, these do not HE will degrade in conventional sewerage systems and áá-J ... - ", - A, £? consequently they will form blockages in the sewer pipes.

Polyethylene oxide (hereinafter PEO) is a hydrophilic polymer soluble in water, - (CH2CH2O) n-, which occurs from the ethylene oxide ring opening polymerization, / \ CH2-CH2 This is available in widely varying molecular weights in the form of a powder from a number of sources, for example, from Union Carbide Coporation (of Danbury, CT). Polyethylene oxide is currently used as a flocculant to improve the deposition of colloidal particles on wood pulp fibers in the papermaking process. It is also used as an additive to modify such properties as the state of aggregate, the sedimentation behavior, the rheology of the polymers used as paints and adhesives. Polyethylene oxide is also used to modify and stabilize polymer networks, for example, by - ».. graft polyethylene oxide chains into a polystyrene network.

Due to its unique interaction with water and body fluids, the present inventors consider it as a component material for personal care and disposable products with water discharge. However, currently available polyethylene oxide resins are not practical for the formation of thin films by melt extrusion or for personal care product applications for several reasons.

For example, even when low molecular weight polyethylene oxide resins have pressure properties melt and melt viscosity desirable for extrusion processing, these have low melt strength and low melt elasticity which limit their ability to be pulled into films having a thickness of less than about 2 mils . The films produced from low molecular weight polyethylene oxide also have a low tensile strength, low ductility, and are very brittle for commercial use.

The weight polyethylene oxide resins Higher molecular, on the other hand, must produce films that have improved mechanical properties compared to those produced from a low molecular weight polyethylene oxide. The higher molecular weight polyethylene oxide, however, has a poor processing and a poor melt pull due to its higher melt viscosity. Melt pressure and melting temperature must be significantly elevated during the extrusion of melting of the higher molecular weight polyethylene oxide, resulting in degradation of the polyethylene oxide and a severe fracture of the melt. Therefore, only very thick films of about 7 mils or greater in thickness of the higher molecular weight polyethylene oxide can be made. Films of this thickness are not practical for waste applications with water discharge.

Attempts to extrude with melted polyethylene oxide often result in severe degradation of the polyethylene oxide. Even when a film can be formed, the polyethylene oxide undergoes morphological changes such as crystallization and aging, when cooled from melting and exposed to the surrounding environment. These changes affect the mechanical properties of the film, resulting in a film that is weak and brittle, which has a resistance to tearing and elongation at very low breaking, and therefore is not suitable for the production of personal care products. What is required in the art, therefore, are a means to overcome the difficulties in processing "te.-melted polyethylene oxide resins and to improve the ductility and flexibility resulting from the thin films formed thereof.

It is known in the art to modify water-insoluble polymer resins, such as polystyrene and polypropylene, by incorporating the soft rubber particles in the polymer structure to improve the polymer's flexibility, to reduce its modulus, and to improve the softness and flexibility of the resulting material. The modifier may be a rubber-type elastomer, a core-shell modifier, or another polymer, such as butadiene-styrene polymers and acrylic polymers. The incorporation of the modifier can significantly reduce the elastic modulus of the polymer under tension. This can also initiate the process of energy dissipation in the polymer structure during deformation resulting in the breaking elongation increased in increased flexibility and improved resistance to tearing. The efficiency of the modifier depends on the composition of the / specific polymer base, the blend morphology, phase structure, and atiezadores mechanisms and process conditions.

The modifier can be incorporated into the base polymer through several different processes. One such process is that of melting mixing methods .j yes? gt & f- ^ vi ^ B-a &amp- conventional. These methods involve mixing a base polymer mixture with thermoplastic elastomers or particulate rubbers. The highly dispersive and distributive mixing required is finally achieved with twin-screw extruders or top-cut mixers under high-temperature and high-cut conditions. Another such process is to mix liquid rubber with a monomer of the desired base polymer followed by polymerization of the mixture under conditions resulting in controlled phase-rubber separation. 10 There are two types of modifier / polymer base systems which can be formed: a dispersed system and a network system. In the dispersed system, the base polymer is a matrix through which the particles are dispersed modifiers. In a network system, the base polymer is present in the form of particles or islands which are surrounded by thin layers of elastomer modifier to form a network type honeycomb. Both types of systems exhibit highly dispersed and very fine morphologies. 20 Dispersed systems typically exhibit two quenching mechanisms which provide additional energy absorption in the polymer under tension. A mecarismo is the preferred formation of cracks or cracks in the rubber particles, for example, mini cracks supporting the tension with the stretched polymer fibrils. This type of '? ^^ ^ ¿¿¡^^^^^^^^^^^^^^^^^^^^ r ^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ absorption of energy? f, was observed in high impact polystyrene and many "erases polymer acrylonitrile-butadiene-styrene (ABS) Another mechanism is the shear deformation between the modifier particles, for example the multiple cut 5. This type of energy absorption was observed in propylene and modified impact polyamide.

Network or honeycomb systems exhibit a third mechanism of energy absorption in addition to the two mechanisms exhibited by the dispersed systems. In this third mechanism there is an intensive performance of the thermoplastic particles within the meshes of the network, for example, the performance of multiple particles.

The polyethylene oxide can not be efficiently modified by the prior art methods described above. It is difficult to process with polyethylene oxide melted under the conditions required to incorporate the prior art rubberized modifiers into the polyethylene oxide matrix because the polyethylene oxide is very sensitive to the upper cut and the high temperature. Attempts to modify the polyethylene oxide in this manner result in poor thermal stability and induced degradation of the ailta cut. Additionally, the melt mix extruders conventional employ a series of water baths to cool the resulting polymer yarns. Because the oxide of Polyethylene is water soluble and water absorbent, the yarns can not be cooled in this way.

The polymerization of the polyethylene oxide modifier / monomer mixture will require the development of costly and complex steps. The control of the morphology of the resulting mixture will be significantly limited and the success of such a process is unpredictable.

Therefore, there is a need in the art for disposable medical and personal care products that maintain integrity and resistance during use and that degrade in conventional sewer systems. In addition there is a need in the art of processes to modify polyethylene oxide to improve its mechanical and melt processing properties.

Additionally, there is a need in the art for a more flexible, softer and more tear resistant polyethylene oxide. There is also a need for a polyethylene oxide resin that has improved melt processing properties. Furthermore, there is a need in the art for a polyethylene oxide resin which is useful for the production of disposable films with water discharge, thin dispersible films and disposable breathable films with water discharge. ^^ < SS íl ^ 'ésA ^ -.

SYNTHESIS OF THE INVENTION Stated generally, the present invention comprises water dispersible compositions for use in disposable medical and personal care products that have improved flexibility and tear resistance. More particularly, the present invention comprises, in one aspect, mixtures that include polyethylene oxide and latex that provide solid state and processing properties improved when compared to conventional polyethylene oxide. The blends of this invention comprising the polyethylene oxide and the latex possess a unique microstructure which provides a number of advantageous properties when compared to the polyethylene oxide alone. Additionally, the The water present in the latex forms a molecular association with the polyethylene oxide in the mixture, acting as a plasticizer for the polyethylene oxide.

In a second aspect, the present invention comprises processes for modifying polyethylene oxide, by forming a mixture comprising polyethylene oxide and latex, to improve physical and melt processing properties. The process includes mixing or coating polyethylene oxide powder or pellets with a latex emulsion. 25 The amount of emulsion added can vary greatly. Generally, about 60 percent by weight or : &, ¿¿ttfc ¿. ^ £ 3t g¡ | ^ Jg less than the emulsion based on the mixture added to the polyethylene oxide. The mixture is then processed with melt, for example, by extrusion with a twin screw extruder provided with a wire die. The threads of the mixture are collected on a conveyor belt cooled by a fan and cut into pellets.

In another aspect, the present invention comprises films based on polyethylene oxide produced from the mixture. These films can be produced, for example, by compression molding or melt extrusion. These films have improved mechanical properties, such as tensile strength and tear resistance. The films also exhibit a reduced modulus and improved softness, flexibility and ductility. Due to these improved mechanical properties, the films of the invention can be produced at significantly lower thicknesses than those formed only with polyethylene oxide. For example, the films of the invention may have thicknesses of about one thousandth of an inch to about four thousandths of an inch. These can be used to thermally process articles which have improved properties, such as flexibility and dispersibility, on similarly processed articles only of polyethylene oxide. Such items include, but are not limited to fabrics, garments and articles, such as surgical covers, towels, covers, over wraps, suits, covers for the head, face masks, shoe covers, CSR wraps, sponges, bandages, ribbons, inner pads, diapers, linings, wash cloths, sheets, pillow covers, napkins, cloth type outer covers, earplugs for the woman, pads and liners for panties, separator films and any woven, non-woven or otherwise formed materials. Such products can be used in the medical industry, both in hospitals and in outpatient facilities, and in domestic environments. Therefore, it is an object of the invention to modify the commercially available polyethylene oxide resins available in order to improve the processing-melting of the polyethylene oxide. It is another object of the invention to modify the polyethylene oxide in order to thermally process the polyethylene oxide into useful article components without adversely affecting the polyethylene oxide and the properties of the polyethylene oxide. finished item.

It is yet another object of the invention to modify the polyethylene oxide in order to thermoform articles having improved mechanical properties on thermoformed articles of the prior art comprising conventional polyethylene oxide.

Another object of the invention is to provide a process for modifying polyethylene oxide which is fast, economical and efficient.

Another object of the invention is mixtures comprising polyethylene oxide and latex with improved flexibility, stiffness and tear resistance.

Still another object of the invention is that of provide mixtures comprising polyethylene oxide and latex having a unique microstructure of a nanoscale dispersion of fine latex particles in the lamellar structure assembly of the polyethylene oxide resin.

It is a further object of the invention to provide a water dispersible mixture comprising polyethylene oxide and latex having a more crystalline, fine and uniform morphology than that of conventional polyethylene oxide.

Another object of the invention is to provide films based on polyethylene oxide with improved elasticity, flexibility and tear resistance.

It is another object of the invention to provide polyethylene oxide-based film having a rheology ká¿iém ^ ¡U £ & of improved melting over conventional polyethylene oxide films.

More generally, the present invention provides mixtures comprising an emulsion and a polymer or mixtures of polymers which are water soluble and / or water dispersible and films made from these mixtures. Therefore, it is an object of the present invention to modify the water soluble and water dispersible polymers to end. to improve its melting-processing.

It is another object of the invention to modify the water-soluble and / or water-dispersible polymers in order to thermally process the polymers into useful article components without adversely affecting the polymers and the properties of the finished article.

It is another object of the invention to modify the water-soluble and / or water-dispersible polymers to thermoforming articles having improved mechanical properties over the thermoformed articles of the prior art.

Another object of the invention is to provide a process for modifying water soluble and / or water dispersible polymers which is fast, economical and efficient.

.- A - Another object of the invention is to provide mixtures comprising an emulsion and a polymer or mixtures of polymers which are water soluble and / or water dispersible which have a flexibility, rigidity and resistance to improved tearing.

Still another object of the invention is to provide mixtures comprising an emulsion and a polymer or a mixture of polymers which are water soluble and / or water dispersible having a single microstructure d 'a dispersion of fine particles in the whole structural of the polymer.

It is a further object of the invention to provide mixtures comprising an emulsion and a polymer or polymer blends which are water soluble and / or water dispersible having a more uniform fine crystalline morphology than that of water dispersible polymers and soluble in conventional water.

Another object of the invention is to provide films made from mixtures comprising an emulsion and a polymer or a mixture of polymers which are water soluble and / or water dispersible having improved ductility, flexibility and tear resistance. ¿.feel r..j *? 4? It is yet another object of the invention to provide films made from mixtures comprising an emulsion / polymer or a mixture of polymers which are water soluble and / or water dispersible having a rheology of improved melting over conventional films.

These and other objects of the invention are achieved by forming mixtures comprising an emulsion and a polymer or a mixture of polymers which are soluble in Water and / or water dispersible and which are processable in films that are useful in the manufacture of disposable personal care products. More particularly, these and other objects of the invention can be achieved with mixtures comprising polyethylene oxide and latex which are processables in films based on polyethylene oxide that are useful in the manufacture of disposable personal care products.

BRIEF DESCRIPTION OF THE DRAWINGS 20 Figure 1 shows the particle size distribution of rubber in the polyethylene oxide / latex mixture (90/10).

Figure 2 is an electron scanning micrograph illustrating the approximately uniform dispersion of the latex particles in the polyethylene oxide resin.

Figure 3 is an atomic force micrograph demonstrating the unique microstructure of a nanoscale dispersion of the fine latex particles in the polyethylene oxide resin.

Figure 4 illustrates the reduction in size of spherulite by the addition of latex particles to the polyethylene oxide resin.

BRIEF DESCRIPTION OF THE PREFERRED INCORPORATIONS In order to overcome the problems in the art associated with the formation of polymer films composed of water-soluble or water-dispersible polymers, the present inventors have developed a process for modifying polymers, such as polyethylene oxide, with an emulsion, such as a latex emulsion. The resulting mixtures have improved processing properties and produce films having properties superior to those produced from the water soluble or water dispersible polymer only.

The particular embodiments of the present invention will be described in terms of the preferred mixture comprising polyethylene oxide and latex. However, it should be understood that any water-soluble or water-dispersible polymer and any emulsion as defined herein may be employed in the invention in a similar manner and that the resultant polymer / emulsion classes will have similarly advantageous properties over the polymers. alone The mixture of the invention comprising polyethylene oxide and latex has a unique microstructure which can be observed by scanning electron microscopy and atomic force microscopy. The polyethylene oxide resin in the mixture has a structural set of lamellae in which there is an approximately uniform nanoscale dispersion of the fine latex particles. In the mixture, both the individual latex particles, from about 100 nm to 200 nm in diameter, and the clusters of the particles, of about a few microns in size, are embedded in the structural assembly of polyethylene oxide lamellae. Atomic force microscopy illustrates the unique microstructure of a nanoscale dispersion of fine latex particles in the lamella structure of the polyethylene oxide resin. Some of the particles form clusters. The particles in the clusters are not packed tightly and do not appear to be coupled (see Figure 3). The microscopy of ? - "- y_j Kgs &iJJ * g., -" * "electronic scan illustrates the approximately uniform dispersion of the latex particles in the polyethylene oxide resin (see Figure 2).

Analysis of thermal properties using Differential Scanning Calorimetry (DSC) shows that the mixture can exhibit increased crystallinity over polyethylene oxide alone. This increase may be due to the improved molecular mobility of the polyethylene oxide chains in the presence of the emulsion as well as the additional nucleation sites provided by the rubber.

The Differential Scanning Calorimetry data also indicate that the water in the emulsion is bound structurally with polyethylene oxide because the water-melt transition does not occur during the cooling / heating cycle. The binding water functions as a plasticizing agent for polyethylene oxide, improving its processing properties and solid state. The mixture comprising polyethylene oxide and latex also exhibits a lower melt viscosity, as determined by a capillary rheometer, than that of polyethylene oxide alone. For example, mixtures having a The ratio of 70/30 polyethylene oxide / latex have shown a 30 percent reduction in melt viscosity.

^^^^^^^^^^^ J ^^^^^^^^^^^^^^^^^ = ^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^ This viscosity reduction is exhibited over a wide range of cutting rates and provides an improved processing of the mixture over conventional polyethylene oxide. This allows the mixture to be processed at lower temperatures, reducing the degradation of polyethylene oxide. The lower processing temperatures provide a reduced temperature gradient during cooling of the melt which allows a higher processing rate.

Any polymer resin that is water soluble, water dispersible, or both which can form water-binding compounds can be used in this invention. The invention also contemplates the use of mixtures or more than one such polymer. The non-limiting examples of Such polymer resins are hydroxypropyl cellulose, polyvinyl alcohol, polyethyloxazoline, polyvinyl pylorridone, polyvinyl pyridine, gelatinized starch, nylon copolymers, polyacrylic acid, polyesters or mixtures thereof. The preferred polymer resin is a polyethylene oxide (PEO). The selection of the polyethylene oxide as the preferred resin for the invention is based on the solubility in water and the processability of the melting of the polyethylene oxide. The selection is also based on the availability of polyethylene oxide resins in a broad range of molecular weights.

Polyethylene oxide and other polymers useful in the present invention have properties very different from the water-insoluble polymers used in the prior art. These polymers form a molecular association with water. For example, water molecules form specific hydrogen-bound complexes with the oxygenic ether of the polyethylene oxide chain. This association affects the local movement of the polymer chain to provide a plasticizing effect. Additionally, the formation of polyethylene oxide-water complexes results in the formation of a state other than water in the polyethylene oxide matrix. Single water does not exhibit a detectable phase transition over the temperature range normally associated with volumetric water. In other words, the bound water does not freeze or boil. This allows the use of water-based emulsions, which have finally dispersed latex particles of a controlled morphology and size, to modify the polyethylene oxide or other polymer.

The water-insoluble polymers of the prior art can not be modified by the methods of the present invention because they do not have the ability to form a molecular association with water. Therefore, the water present in the emulsions of the present invention will exist as 'free water' rather than as 'bound water' in any composition formed between the water-insoluble polymers of the prior art - and The emulsions used in the present invention are described. Such free water will undergo phase transitions during melt processing, resulting in microscopic holes and weak spots in the film. Films produced from such polymer / emulsion compositions will have reduced abrasion resistance and reduced fracture toughness, the true problems solved by the present invention.

The polyethylene oxide resins useful in the practice of this invention can be of any molecular weight. Preferred polyethylene oxide resins have an average molecular weight ranging from about 100,000 g / mol to about 8,000,000 g / mol. Higher molecular weight polyethylene oxide resins are desirable for their increased liquid stability, mechanical strength and ductility, while low molecular weight resins provide better melt flow and film forming properties. Based on these considerations, the especially preferred polyethylene oxide resins of the invention have a molecular weight of between 200,000 g / mol and 4,000,000 g / mol.

Such polyethylene oxide resins are commercially available. For example, polyethylene oxide resins are available from Union Carbide Corporation (of Danbury, CT) under the trade designations Polyox® WSR N-80 (Molecular Weight = 200,000), WSR (Molecular Weight = 300. COO), WSR N-3000 (Molecular Weight = 400,000), and WSR 205 (Molecular Weight = 600,000). Other polyethylene oxide resins available from Union Carbide Corporation within the above average molecular weight range are sold under the trade designations WSR-3333, WSR-N-12K, WSR-N-60K, WSR-301, WSR coagulant, WSR-303.

Emulsions useful in the practice of; The present invention can be any organic polymer emulsion or any dispersion and / or inorganic particle suspension. These emulsions can provide a number of different modifying properties, such as softness, ductility, flexibility and tear resistance for polyethylene oxide.

There are basically two types of organic polymer emulsions, polymers based on acrylic and polybutadiene. Each type can be synthesized through emulsion polymerization techniques which are known in the art. The particle size of the rubber particles (Latex) in the emulsions can be controlled during the polymerization. For the present invention, an average particle size of about 10 nanometers is preferred to few micheras. Emulsions can also be produced in a variety of particle morphologies, such as spherical- ¿^ Gg ^^ i¿fa ^ l ^ g ^ «^^ SI ^ S || Ml '? A. - ** ¡& &git r? -i® *, * ¡S. ító ^? ^ rubberized, covered-glazed / core rubberized, and multiple layers. The morphology can be tailored to provide modifier particles with controlled surface and docile properties. The organic polymer emulsions useful in the present invention include, but are not limited to, polymers of styrene butadiene, acrylics, acrylics of styrene, polyvinyl acetate, acrylonitrile-butadiene-styrene, acrylonitrile and acrylonitrile butadiene. Especially preferred polymer emulsions are GOOD-RITE® 1168 styrene butadiene latex and HYCAR® acrylonitrile-butadiene-styrene latex, each available from BF GOODRICH® Company having offices in Cleveland, Ohio. In particular, suspensions and / or dispersions in inorganic particles useful in the invention include but are not limited to stabilized silica gel dispersions, to spherical silica dispersions of nanoscale, and the dispersions of inflatable clays. The invention is not limited to these compounds but includes any stable dispersion / emulsion in organic or inorganic particles in the form of discrete particles in a stabilizing fluid. 25 The amount of emulsion may vary depending on the particular polymer to be modified, the particular modifier chosen, and the particular properties to be improved, for example, the modifiers for the weight polyethylene oxide. Low molecular weight can be selected and used in quantities that improve the mechanical properties, such as softness, tensile strength and ductility Similarly, modifiers for higher molecular weight polyethylene oxide can be selected and used in high quantities. which lower the lower melt viscosity and improve the pull In general, the emulsion percentage employed is from about 10 to about 60 percent by weight of the mixture, preferably from about 10 to about 50 percent by weight, more preferably from about 15 to about 35 percent by weight of the mixture.

Two other parameters which affect the properties of the mixture are the diameter of the individual particles (particle size) in the mixture and the distance between the particles (distance between particles) within the mixture. These two parameters are interdependent. Your relationship can be defined by the following relationship: A = D ((p / 6V 1/3 - l) wherein A is the distance between particles of said particles within the mixture, D is the particle size of the particles in the mixture, and Vp is the fraction of the particle volume in the mixture, for example the concentration of 5 particles. For the present invention, the particles generally comprised from about 3% to about 30% by weight of the weight of the polymer, preferably from about 5% by weight to about 25% by weight, more preferably from about 8% by weight. Weight at around 20% by weight. The size Average particle size of the particles in the mixture should be from about 10 nanometers to about 20 microns, preferably about 50 nanometers to about 10 microns, more preferably from about 100 nanometers to about 5 microns. 15 The water content of the emulsion is important in the manufacture of films with improved fracture toughness. As indicated above, polyethylene oxide and other water-soluble polymers are capable of forming bound complexes hydrogen with water. This bound water does not exhibit phase transitions. However, the amount of water which can be bound in such complexes is limited in the polyethylene oxide by the number of oxygen ether atoms in the polymer chain. The additional water will remain in the mixture as free water. Free water exhibits phase transitions. These phase transitions can result in microscopic fractures ^ ^ S? ^ a? ^. J? ^ "^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ Which weaken the mix, resulting in films which are more brittle and They have a lower resistance to stress. For the present invention, the water content of the emulsion is such as to produce a mixture having about 5% by weight or less of water, preferably about 20% by weight or less, more preferably about 15% by weight. weight or less of water.

Additional additives may optionally be included in the mixture to provide additional advantageous properties. Non-limiting examples of such additives include plasticizers such as Tween® 20, dyes, pigments, antiblock agents, antistatic agents, slip agents, debanters and antioxidants, for example, Irganox® 1076, Irganox ® 50? 7, and Irganox® 1135 and combinations thereof.

The mixtures of the present invention can generally be produced by combining a soluble polymer in water and / or dispersible in water, or a mixture of such polymers with the emulsion and extruding the mixture. The various incorporations of the process are described, using a polyethylene oxide resin as the polymer and latex emulsions as the emulsion. However, the process can be carried out in a Analogous manner using a water soluble or water dispersible polymer and any emulsion as defined herein.

The polyethylene oxide resin is commercially available only in powder form. However, the present inventors have tested a method for producing polyethylene oxide pellets through extrusion, followed by cooling the polyethylene oxide yarns on a conveyor belt cooled with a fan. Therefore, the present invention encompasses the use of both the polyethylene oxide powder and the polyethylene oxide pellets.

In one embodiment, the process for producing the polyethylene oxide / latex mixture of the invention comprises two phases. In the first phase, the latex emulsion is mixed with polyethylene oxide or coated on powder or polyethylene oxide pellets. In this phase, the water in the emulsion is absorbed in the polyethylene oxide, providing a plasticized polyethylene oxide resin with pre-dispersed rubberized particles on the surface of the plasticized mixture of latex polyethylene oxide and oxide powder or pellets. polyethylene.

In the second phase of the process, the plasticized mixture of polyethylene oxide and latex is fed into a twin screw extruder or a high cut mixer to provide mixing with melted polyethylene oxide and rubber particles.

In another embodiment, the process comprises a single step. When practiced as a single step, the pellets or the polyethylene oxide powder and the latex emulsion are either added together directly into the extruder supply section, or the polyethylene oxide is added to the supply section of the extruder, and the latex emulsion is later added downstream. Due to the challenges of supplying a large amount of viscous latex inside the extruder, it is preferable to carry out the investment in two phases.

The polyethylene oxide can be mixed or coated with the latex emulsion by any means, for example, with a Brabender Plasticorder, a roller mill, or a ribbon mixer. Advantageously, the polyethylene oxide pellets are mixed with the latex emulsion using conventional stirring techniques or a ribbon blender. A preferred method for coating the polyethylene oxide powder with the latex emulsion is with a spray gun. spray of upper air pressure while the powder is being mixed in a ribbon blender.

The device used to form the polyethylene oxide / latex mixture should be designed to provide a higher melting melt processing, a residence time for mixing the polyethylene oxide and d = the latex emulsion, and a potential for higher rate processing. Such devices include top-cut mixers, single screw extruders, and twin screw extruders, with said twin screw extruders being preferred. Non-limiting examples of twin screw extruders to provide superior melting cut and increased dwell time are the twin screw extruder Haake TW-100 and the twin screw extruder Werner & Pfleiderer ZSK-30. Such an extruder has a section of supply, one or more heated extrusion zones, and a yarn array. The polymer yarns produced are collected on a conveyor belt cooled with a fan. The supply section of the extruder is cooled with water to prevent premature melting of the polyethylene oxide resin. The The temperature in each of the heated zones may be the same or different and is controlled separately. The number of zones can be varied depending on the molecular weight of the polyethylene oxide and the number and type of the latex emulsions employed. The thread matrix used to create the threads of The polymer that will be cut into pellets optimally has holes of about 3 millimeters in diameter to provide a sufficient surface area for cooling.

The general temperature range for the mixing process is from the Tm (melting temperature) of the oxide of polyethylene used at the decomposition temperature of polyethylene oxide. This temperature range is generally from around 75 degrees centigrade to around 250 degrees centigrade. The preferred temperature range is from about 85 degrees centigrade to about 220 degrees centigrade, more preferably from about 100 degrees centigrade to about 200 degrees centigrade. Temperatures in excess of 250 degrees centigrade will result in excessive thermal degradation of the components. Higher initial temperatures are required to produce the mixture of the polyethylene oxide powder than the polyethylene oxide pellets due to the greater difficulty in melting the powder.

The cutting rate is important to form a uniform mixture. The cut rate will depend on the particular components used and the desired properties of the final mix. For example, higher molecular weight polyethylene oxide requires more cutting for mixing than does low molecular weight polyethylene oxide. The mixing of the polyethylene oxide powder requires higher cutting rates than the mixing of polyethylene oxide pellets. In general, a screw speed between about 30 revolutions per minute and about 1200 revolutions! per minute will produce an adequate cut rate.

The mixture of the present invention can be manufactured into films or sheets by any conventional method, for example compression molding, extrusion casting or melt blowing. In a preferred embodiment, the mixture is extruded using a Haake twin screw extruder having a 4 inch slot die. The resulting film is collected on a cooled coiling roll. The mixture is extruded at temperatures between about 80 degrees Celsius and about 150 degrees Celsius, preferably about 100 degrees Celsius and about 125 degrees Celsius and the winding roller cooled is maintained at a temperature of between about 15 degrees and about 20 degrees Celsius. The thickness of the produced film can be adjusted by varying the matrix spacing, the screw speed and the winding speed. Optimally, these parameters are adjusted to produce a film which has a thickness of between about 1 thousandth of an inch and about 4 thousandths of an inch.

The present invention also encompasses films made from the mixture. These films exhibit a combination improved mechanical properties; such as the reduced module, the increased flexibility, the softness, the ^^^^^^^^ r ^^^^^^ ^^^^^^^^^^^^ • Vfr ductility, elongation at break, the tensile strength and tear resistance; and the desired levels of ability to breathe. These improvements in tension behavior are a result of the unique morphology of the mixture.

The stress properties include the Young modulus, the tensile stress at break, the deformation energy at break, and the elongation (% tension) at break. The voltage properties can be measured, for example, with a Sintech voltage tester (SINTECH I / D) using the Testworks 3.03 program (from MTS System Company of Cary, North Carolina). The films of the present invention were evaluated in both the machine direction (MD) and the transverse direction (TD). The direction of the machine is the direction along which the film is moved during manufacturing or processing. The transverse direction lies perpendicular to the direction of the machine generally along the plane of the film.

Films made from the blend exhibit a decrease in the modulus, especially at a latex emulsion load of 25 percent by weight or more. This decreased module results in increased flexibility and smoothness.

Films comprising the blends of the invention also exhibit an elongation to breakage increased and generally exhibit an increased resistance to friction when compared to films made of conventional polyethylene oxide. The increase in these properties contributes to the significant increase in the specific energy required to break the films compared to that required to break the films formed of conventional polyethylene oxide.

In a dry state, films made of the polymers of the present invention can have a machine direction tensile strength (MD) of between about 3 Mega-Pascal (MPa) and about 150 Mega-Pascal. Preferably, the tensile strength of the film in the machine direction is between about 8 Mega-Pascal and about 100 Nega-Pascal, with improved performance and processability during subsequent manufacturing operations achieved to tensile strengths. of approximately 50 Mega-Pascal or less. The dry stress resistance of the film in the transverse direction (TD) is between about 3 Mega-Pascal and about 150 Mega-Pascal, preferably between about 6 Mega-Pascal and about 100 Mega-Pascal, with the most preferred range not exceeding 50 Mega-Pascal.

The percent elongation at the breaking of the film can be determined by the following formula: where Lf is the final length of a film sample at break and Lx is the initial length of the film sample before elongation. The films of the present invention have an elongation to the break in the direction of the machine between about 30% and about 1500%, preferably between about 80% and about 1000%, more preferably between about 150% and about 1000%. The films exhibit an elongation at break in the transverse direction of between about 30% and about 1500%, preferably between about 50% and about 1000%, more preferably between about 100% and about 1000%.

The tear strength of the films of the invention was measured by the test method ASTM D 1938-94 and reported as a maximum load and total energy. Each of these factors were evaluated in both the directions of the machine and the transverse of the film. The maximum load for tear propagation was normalized to the cross section 25 of the film in the direction of tearing to make a minimum film thickness effect. The films that comprise the | ^^ ^ ^^^ - ^ j ^ j¡ | ^ g | ^ mixture of polyethylene oxide and latex were able to withstand a maximum load significantly higher than that of the film made of only polyethylene oxide.

The total tear energy was normalized to the volume of a section of the uncut film to take the thickness of the film into account. This allows an exact comparison between the films having different thicknesses. The films of the present invention exhibit a dramatic increase in energy absorption during tear propagation compared to simple polyethylene oxide films.

The ability to breathe of the films can be determined by measuring the vapor transmission rate of water (WVTR). The water vapor transmission rate for the films can be calculated using the standard ASTM method E96-80 described in Example 11.

Films comprising the blends of the invention also exhibit improved breathability over films made of conventional water insoluble polymers. The ability to breathe is an important property in personal care products made from films because it allows the product to dry during use, reducing moisture against the skin. Therefore, the increased breathing capacity of the film reduces the skin breakage, redness, irritation and infection associated with retained moisture.

Conventional films made of water-insoluble polymers have very low water vapor transmission rates, and therefore a diminished ability to breathe. This problem is overcome in the prior art by means of the addition of fillers followed by the stretching of the film to produce pores which provide breathing capability to the final product. One type of filler which is used in the prior art is calcium carbonate. The overall breathability of such products as measured by a water vapor transmission rate will range widely from about 500 g / square meter. / 24 hours / thousandth of an inch (grams per square meter, per 24 hours, per 0.001 inches of film thickness) to about 5000 g / square meter / 24 hours / thousandth of an inch depending on the filler used, the amount of the filler used , the amount of the filler used and the amount by means of which the film is stretched. In general, the films of the present invention provide increased water vapor transmission rates of between about 300 g / square meter / 24 hours / thousandth of an inch and about 20,000 g / square meter / 24 hours / thousandth of an inch, preferably between about 800 g / square meter / 24 hours / thousandth of an inch and about 7,000 g / square meter / 24 hours / thousandth & * '3 yttj inch. More preferably, the films of the present invention exhibit a water vapor transmission rate of about 1,700 g / square meter / 24 hours / thousandth of an inch to about 1,000 g / square meter / 24 hours / thousandth of an inch without stretching and without the formation of pores. The ability to breathe in the films of the present invention is a result of the higher water vapor transmission rate of polyethylene oxide.

These superior properties make the films of the invention very suitable for use in disposable personal and medical care products with water discharge. Such products include, but are not limited to, surgical covers, towels, covers, over wraps, suits, head coverings, face masks, shoe covers, CSR wraps, sponges, bandages, ribbons, interior pads, diapers, linings , washing rags, sheets, pillowcases, napkins, p &g type outer covers year, feminine plugs, pads and linings for panties, separator films, and any woven, non-woven or otherwise formed materials. These materials can be used in the medical industry, both in hospitals and in external patient facilities and in a domestic environment.

For the production of such products the films of the invention may be subjected to a selected plurality of stretching operations such as uniaxial or biaxial stretching. Stretching operations can provide the film with increased softness, improved touch properties, increased breathability, and reduced thickness. The film can also be further processed to improve film properties by tempering the film at elevated temperatures; by spraying the film with an active surface fluid to impart water repellent properties or to moisture to the film; or by modifying the physical state of the film with ultraviolet radiation, an ultrasonic treatment, or a high-energy radiation treatment. In addition, the subsequent treatment of the film can incorporate a selected combination of two or more of the techniques previous Additionally, the films of the present invention can be co-extruded or coated with a thin barrier layer, such as a resin to provide a layer barrier to moisture or water. The barrier layer may constitute about 3 to about 20% of the overall caliber of the film. Examples of resins that may be used for such barrier layers include, but are not limited to polycaprolactoma, acrylic acid copolymers Ethylene, polybutylene succinate, such as Bionolle® and Kraton® resins. fef * ^ ^ ES ¿X '^ U > . - ~ * • "" * - - ^^^ fa s, -? For the applications in personal care products, the films of the invention may be etched or otherwise provided with a matte finish to exhibit a more aesthetically pleasing appearance. The films can also be optionally laminated with a non-woven fabric. Examples of fibers suitable for the non-woven fabric include, but are not limited to, organic fibers, such as cellulosic fibers, and synthetic fibers made of thermoplastic polymers, such as polyester, polyamide and polypropylene. The non-woven fabric can be generally coated or treated to impart a desired level of liquid and / or vapor / moisture impermeability.

This invention is further illustrated by the following examples which should not be considered in any way as imposing limitations on the scope thereof. On the contrary, it should be clearly understood that several other additions, modifications and equivalents thereof should be used which, after reading the description given herein, may also be suggested to those skilled in the art without departing from the spirit of the present invention. and / or of the scope of the appended claims.

E J E M P L O S EXAMPLE 1 (COMPARATIVE) & jfe t'U 175 parts of polyethylene oxide resin (PEO) of POLYOX® WSR N-3000 in powder form (from Union Carbide Corporation) were mixed with 24 parts of plasticizer, Tween® 20 (from ICI Americas Inc. .), and 1 part antioxidant, Irganox® 5 1076 (from Ciba Specialty Chemicals Corporation), and mixed and pelleted using a twin screw extruder and an air-cooled strip at Planet Polymer (San Diego California). To produce a film of this mixture, the pellets were fed into a laboratory-scale Haake TW-10 100 twin-screw extruder to which a 4-inch slot die had been attached. The temperatures for the four heat zones in the extruder were 100 ° C, 100 ° C, 110 ° C, 110 ° C, and 125 ° C. A rolling roller, maintained at 15-20 ° C, was used to melt the film. A control film containing 87.E > % from N3000 polyethylene oxide, 12% plasticizer and 0.5% antioxidant (by weight) was produced which had a thickness of about 3 mils. The tension and tear properties of this film are given in Table 1. During the tear test, this film experienced failure by tearing in the machine direction in a tension failure in the transverse direction.

EXAMPLE 2 The polyethylene oxide pellets were produced with a plasticizer and an antioxidant as in Example 1. 90 parts of these pellets were mixed with 10 parts of an emulsion of styrene-butadiene (SB) Good Rite® SB 1168 (from BF Goodrich), using a conventional stir-up technique. This produced pellets which were coated with emulsion and agglomerated somewhat. The pellets were then supplied into the twin screw extruder Haake described in Example 1. Due to the small L / D ratio of the laboratory scale Haake extruder, the compound was extruded twice to improve the rubber dispersion. The extruder barrel temperatures were 80 ° C, 80 ° C, 85 ° C and 87 ° C for the first run and 110 ° C, 110 ° C, 120 ° C, and 120 ° C for the second run. The screw speed was 60 revolutions per minute. Some evaporation of the volatiles was observed during the extrusion. The melted yarns were cooled by air on a conveyor belt and pelleted. A soft extrusion, uniform and smooth, was obtained from the second extrusion. The pellets of this SB / polyethylene oxide emulsion mixture were melted into a film using the procedure described in Example 1. This film had a thickness of about 1.5 mils and an SB emulsion content of about 10% by weight. weight. The tensile and tear properties of the film of this Example can be found in Table 1. During the scratch test, this film experienced stress failure in both machine and transverse directions.

EXAMPLE The mixture of this Example was produced by the procedure of Example 2, except that 70 parts of the polyethylene oxide pellets of Example 1 were mixed with 30 parts of the styrene-butadiene emulsion 1168 (SB) Good Rite® SB. A film of this mixture is produced following the procedure of Example 1. The film had a thickness of about 3 mils and an emulsion content SB of about 30% by weight. The tension and tear properties of this film are given in Table 1. During the tear test, this film experienced failure due to machine direction tearing and tension failure in the transverse direction.

EXAMPLE 4 The mixture of this Example was produced by the procedure of Example 2, except that 50 parts of the polyethylene oxide pellets of Example 1 were mixed with 50 parts of the styrene-butadiene emulsion SB 1168 Good Rite®. It was evident from the excess evaporation during mixing that a large amount of free water was present in this formula. As a result of this, the melted threads of this mixture were porous and uneven. A film of this mixture is produced following the procedure of Example 1. The Faith, mXfc i dSfak, * Jir45 film had a thickness of * about 13 mils and an emulsion content of styrene butadiene of about 50%. The tension and tear properties of this film are given in Table 1. During the tear test, this film experienced failure by machine direction tearing and tension failure in the transverse direction.

The tensile properties of the stiffened polyethylene oxide films of the present invention are determined using the test strip configuration of a Sintech voltage tester (SINTECH l / D) and the Testvvorks 3.03 program (from MTS System Company of Cary, North Carolina). The test was carried out with a load cell of 25 pounds (110 N), and handles of 3 inches (7.6 centimeters) coated with rubber and powered by air. The film test was carried out with a measurement length of 1 inch (2.54 centimeters) and a cross head speed of 5 inches / minute (12.7 centimeters / minute). A sample of individual dog bone type film was calculated perpendicular and in the center d 'the handles, and it stayed in place when the air pressure closed the handles together. The thickness of the film was entered by the user during the beginning of the stress test. In each sample, the film was stretched until the break occurred. The program was then used to create a stress graph against stress and calculate the desired mechanical properties for the sample.

The energy * ae deformation at breakage per unit volume of the material was determined by the area under the stress / strain curve divided on a product of cross-sectional area of the film and a calibrated length. To obtain the desired average stress properties, five film specimens were cut in both the machine and transverse directions (MD and TD) and tested for the individual blend composition. The tearing properties of the films were measured by the tear propagation standard for determining the tear resistance of plastic film and the formation of thin sheets by a unique tearing method (ASTM D 1938-94). The maximum load for tear propagation was measured and normalized by the cross-sectional area of the film to take into account an effect thickness of film. The total tearing energy was normalized by the volume of the uncut portion of the film-test strip. In some cases, the failure occurred as a result of a stress stretch of the test-film specimen rather than as a result of the tearing of the specimen. This fails was designated as a voltage failure rather than a tear failure.

To obtain the desired average tear strength properties, five specimens were cut from film in both directions of the machine and cross IMD and TD) and were tested for the individual blend composition.

TABLE 10 20 EXAMPLE S * i * sJM The mixture of this Example was produced by the procedure of Example 2, except that 90 parts of the polyethylene oxide pellets of Example 1 were mixed with 10 parts of styrene-butadiene rubber emulsion. 5 acrylonitrile (ASB) from HYCAR® 1580 (from BF Goodrich). A film of the pellets of this mixture was produced following the procedure of Example 1. The film had a thickness of about 2 mils and a HYCAR® emulsion content of about 10% by weight. The tensile and tear properties of this film are given in Table 2. During the tear test, this film experienced the tearing failure in the machine direction and the transverse direction in the transverse direction.

EXAMPLE 6 The mixture of this Example was produced by the procedure of Example 2, except that 70 parts of the polyethylene oxide pellets were mixed with 30 parts? acrylonitrile styrene butadiene emulsion HYCAR® 1580 (ex. BF Goodrich). A film of this mixture was produced following the procedure of Example 1. The film had a thickness of about 2.5 mils and a HYCAR® emulsion content of about 30% by weight. The tension properties and tearing of this film are provided in Table 2.

-A U; »^ Ó ^ r ^ -SÁ ^. ¡G ^^ | ^ gbgg ^^^^ »^ gfi During the tear test," this film experienced a voltage failure in both directions of the machine and across.

EXAMPLE 7 5 parts of POLYOX® WSR N-3000 (PEO) resin were mixed in powder form (Union Carbide Corporation) with 48 parts of Tween® 20 (from ICI Americas Inc.), and 2 parts of Irganox® 1076 ( Ciba Specialty Chemicals Corporation) using a mixer of tape. The powder was then coated with 100 parts of styrene-butadiene emulsion SB 1168 Good Rite® (from BF Goodrich) using a high-pressure spray gun, while the powder was still mixed in the ribbon mixer. The coated powder was then supplied to an extruder of twin screw available from Planet Polymer Technologies (San Diego, California). The temperature of the supply zone was 180 ° F; the barrel area was 250-300 ° F; the adapter was 300-320 ° F, and the die temperature was 320 ° F. The screw speed was 250 revolutions per minute, and the rate of supply was 85-100 revolutions per minute. The melted yarns were air cooled on a conveyor belt and pelleted. The use of higher processing temperatures in Planet Polymer Technologies compared to the processing temperatures used with the Haake extruder of the laboratory scale resulted in more intensive evaporation of volatiles, including water. The -36. »S? - > ^^ & & amp; * rfí¡ s? Processing conditions, however, were optimized to obtain uniform and solid strands of the mixture which were pelleted using an air-cooled conveyor belt. These pellets were then cast in a film using the procedure of Example 1. The film had a thickness of about 5 mils. The tension and tear properties of this film are given in Table 2. During the tear test, this film experienced a voltage failure in both the machine and transverse directions.

EXAMPLE The mixture of this Example was produced by the procedure of Example 7, except that 117 parts of resin polyethylene oxide POLYOX® WSR N-3000 in powder form were mixed with 32 parts of Tween® 20, one part of Irganox® 1076 and 50 parts of styrene-butadiene emulsion SB 1168 Good Rite® to produce the mixing pellets . These pellets were converted into a film following the procedure of Example 1. The film had a thickness of about 2.5 mils. The tension and tear properties of this film are given in Table 2. During the tear test, this film experienced failure due to machine direction tearing and voltage failure in the direction transversal. ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^^^^^^^^^^^^^^^^^^^ fifteen twenty 30 35 EXAMPLE The mixture of this Example was produced by the procedure of Example 7, except that 121 parts of POLYOX® WSR N-75D polyethylene oxide resin were mixed in powder form with 28 parts of Tween® 20, one part of Irganox® 1076 and 50 parts of Good Rite® SB 1168 styrene butadiene emulsion to produce the mixing pellets. These pellets were converted into a film following the procedure of Example 1. The film had a thickness of about 2.5 mils. The tension and tear properties of this film are found in Table 3. During the tear test, this film experienced the failure by tearing in the machine direction and voltage failure in the transverse direction.

EXAMPLE 10 The mixture of this Example was produced by the procedure of Example 7, except that 105 parts of POLYOX® WSR N-750 (PEO) resin were mixed in powder form with 44 parts of Tween® 20, one part of Irganox® 1076 and 50 parts of styrene butadiene emulsion SB 1168 Good Rite® to produce the mixing pellets. These pellets were converted into a film following the procedure of Example 1. The film had a thickness of about 2.5 mils. Due to the superior ficador in this film, some of the mixture of Tween 20 bled out on the surface of the film. The tensile and tear properties of the film are given in Table 3. During the tear test, this film experienced failure by tearing in the machine direction and failure by tension in the transverse direction.

TABLE 3 fifteen twenty EXAMPLE 11 5 Ability to Breathe The water vapor transmission rate (WVTR) values for the films of Example 1 and Example 9 were calculated according to the ASTM standard number E96-80. The circular samples measuring 3 inches in diameter were cut from each of the test materials and from a CELGARD® 2500 microporous film control which is available from Hoechst Celanese Corporation. Individual samples of test materials and control material were placed through the open top portions of the individual vapometer cups containing one hundred milliliters of distilled water. The bolted flanges were tightened to form a seal along the edges of the cup. The cups were placed in a convection oven at 100 ° F. Humidity relative inside the oven was not specifically controlled. The covers were weighed and immediately placed in the oven. After 24 hours, the cups were removed from the oven and weighed again. The water vapor transmission rate of each material was calculated based on weight loss and the water vapor transmission rate of the control film, assuming that the water vapor transmission rate of the CELGARD® 2500 microporous film is 5000 g / meter ^ w- < • $ ** - * - ^^ r j ^ «square / 24 hours under predetermined established conditions. The ability to breathe of the film (water vapor transmission rate) produced in Example 1 was 2000 g / square meter / 24 hours, while that of the film produced 5 in Example 9 was 1750 g / meter square / 24 hours.

EXAMPLE 12 The melt rheology of polyethylene oxide, PEO N-3000, and various mixtures comprising polyethylene oxide and latex were measured using a Gottfert Rheocraph 2003 capillary rheometer with a 2.31 WinRHEO analysis program. A 2000 pressure rod transducer was used with the 30 / 1.0 / 180 round hole capillary matrix. The viscosity of 15 melted in Pa sec was measured at various cutting rates of 50, 100, 200 and 1000 revolutions per minute and at temperatures of 125 ° C and 175 ° C.

The results at 125 ° C are presented in Table 4 and the results at 175 ° C are presented in Table 5.

TABLE • ^^ P-to »- * &'$ & * AS¿», ft * - *' ^^ - J-¿fc- EXAMPLE 13 A thermal analysis of several polyethylene oxide mixtures was carried out using a Thermal Analyst (TA) 2910 Differential Scanning Calorimeter (DSC) with a TA Analyst 2200. All tests were carried out under an atmosphere of N, the results were evaluated using the DSC4.0 analysis program, and the melting temperature (Tm) was quantified and was presented in Table 6. 25 TABLE 3 0 EXAMPLE 14 The thin cross sections of an extrudate of each of the mixtures of Examples 2, 3 and 4 were prepared by cryomicrotomy using a cryo-ultramicrctome Reichert UltraCut S FCS equipped with a Diato e diamond cryo blade. The cut at Crio temperature was carried out for Tighten the polymer enough to avoid smearing.

The spherulite size analysis of the latex / hardened polyethylene oxide mixture was carried out using polarized light optical microscopy. For light microscopy When polarized, sections three micrometers thick were cut at a sample temperature of -80 ° C and at a knife temperature of -80 ° C. In the case of the large diameter extrudate, the specimen was cut to a block face size of about 1 mm2. To minimize severe curling of the In the section that occurs during cutting, a sectioning speed of 0.2 mm / second was used. The crimping required that the sections be guided out of the blade edge with a flange probe and then delicately rolled and flattened on the glass inspection plate. Care must be taken of .. & J¡ £ ií-sto ^ £ tó- ^ U ^ iSéé ?,, ^ ^ M avoid the damage to the process, since these are very soft and somewhat self-conscious.

After the sections were flattened on the platen surface, they were mounted using a Resolve® non-drying medium and slipped in a covered manner. These were examined using a cross polarizer or partially crossed in an Olympus BH-2 microscope. Polaroid® photomicrographs were taken at fixed magnifications of 75x and 150x.

The spheruril size measurement was carried out by examining the photomicrographs of polarized light in the personal computer based on the image analysis program, ImageTool VI.25 (available via the Internet, free from the University of Texas Health Science Center, of San Antonio). The calibration measurement was made using a phase micrometer (Graticules, Limited, Kent, England) based on the divisions of 10 microns. Twenty spherulites were measured per sample and the results were tabulated on an extended leaf, from which the average spherulite size was determined (see Figure 4).

EXAMPLE 15 ?? ^ ß? ^ ¡g | Mixture of Example 2 were purchased using an Environmental Secondary Electronic Microscope (ESEM) model E-2020 (from ElectroScan Corporation of Wilmington, MA). The images were acquired in a file-labeled image format (TIFF) and were of a resolution of 1024 by 1024 pixels. The images also possessed a miera bar (10 or 25 μm) for purposes; of calibration. (See Figure 2).

After the images were acquired, they were transferred to a Quantimet 600 IA system (from Leica, Inc., of Deerfield, Illinois). An image analysis program was written using the QUIPS operation program present in the Quantimet 600. This program carried out the following functions: acquired the image, carried out a calibration, detected latex particles, carried out image processing , measured percentage of covered area and particle size and output data, such as main values, statistics, a distribution histogram size, and image. (See Figure 1). The particle sizes were measured using a derived parameter of equivalent circular diameter (ECD): ECD = (4 x Area / p) 1/2 The percent of Area covered by latex particles = 1 .25 The particle count through equivalent circular diameter is as follows: Total 420.58 # of Particles Main 0.48 μm Division of Standard Deviation 0.34 μm Standard Error 0.01 Maximum 2.85 μm Minimum ,? 0.11 μm EXAMPLE 16 The atomic force microscopy image of the mixture of Example 3 was obtained by using a Multimode® scanning probe microscope (from Digital Instruments, of Santa Barbara California) SPM, Nanoscope® Illa, by employing the Tapping Mode with a phase image formation. A type microscope combined with the Nanoscope was used to place the probe on the cross section of the mixture. For atomic force microscopy, the cross sections of the extrusion of the latex / polyethylene oxide mixtures are were prepared by cryo-microtomy using a Reichert UltraCut S FCS cryo-ultramicrotome equipped with a Diatome diamond cryo-blade. Cryo temperature sectioning was required to fix the polymers sufficiently to avoid smearing. The block cross sections were prepared at a sample temperature of -80 °, and the temperature of the blade was also set to -80 ° C. In the case of the large diameter extrudate, the specimen was cut to a block face size of about 1 square millimeter. A dispersion of latex particles in the lamella structure of the mixtures of polyethylene oxide / latex was analyzed using the atomic force microscopy technique (See Figure 3). * '* * * * * -dj ^^^ ^ ^^^ * ^. (£ - - ^ - ^ - A- The examples given above are intended to be demonstrative rather than limiting of the incorporations contemplated by the invention and covered within the scope of the claims.

Claims (21)

1. A mixture comprising an emulsion and one or more water-soluble and / or water-dispersible polymer resins wherein the emulsion particles are distributed through the polymer matrix and the water in the emulsion forms the hydrogen bonds with the polymer molecules.
2. 2. The mixture as claimed in clause 1 characterized in that the polymer resin is selected from the group consisting of polyethylene oxide (PEO), hydroxypropyl cellulose, polyvinyl alcohol (EVA), polyethyloxazoline, polyvinyl pyrrolidone, polyvinyl pyridine, gelatinized starch , nylon copolymers, polyacrylic acid, polyesters, and mixtures thereof.
3. 3. The mixture as claimed in clause 2 characterized in that the polymer resin is a polyethylene oxide resin.
4. 4. The mixture as claimed in clause 1 characterized in that the emulsion comprises a polymer or copolymer selected from the group consisting of styrene butadienes, acrylics, styrene acrylics, polyvinyl acetate, acrylonitrile-butadiene styrenes, acrylonitriles, and acrylonitrile butadienes.
5. 5. A process for preparing a mixture comprising an emulsion and one or more water-soluble and / or water-dispersible polymer resins comprising the steps of: (a) mixing or coating the polymer resin with an emulsion, optionally in the presence of a stabilizer, a plasticizer, a filler or an additive; (b) supplying the polymer and emulsion mixture formed in step (a) inside an extruder; (c) heating and extruding the combination to produce a mixture; Y (d) cooling the mixture produced.
6. 6. The process as claimed in clause 5 characterized in that the mixture also comprises a plasticizer.
7. 7. The process as claimed in clause 5 characterized in that the mixture also comprises a stabilizer.
8. 8. The process as claimed in clause 5 characterized - because the melted yarns are cooled by air on a conveyor belt.
9. 9. The process as claimed in clause 5 characterized in that the polymer resin is selected from the group consisting of polyethylene oxide (PEO), hydroxypropyl cellulose, polyvinyl alcohol (FVA), polyethyloxazoline, polyvinyl pyrrolidone, polyvinyl pyridine, gelatinized starch , nylon copolymers, polyacrylic acid, polyesters, and mixtures thereof.
10. 10. The process as claimed in clause 9 characterized in that the polymer resin is a polyethylene oxide (PEO) resin.
11. 11. A process for preparing a mixture comprising polyethylene oxide and latex comprising the steps of: (a) mixing the polyethylene oxide powder resin with a plasticizer and a stabilizer; (b) coating the polyethylene oxide powder with a latex emulsion using a high pressure air spray gun while mixing with a ribbon blender; (c) feeding the coated polyethylene oxide powder into a twin screw extruder; (d) heating and extruding the coated polyethylene oxide powder to form a mixture, wherein the extruder temperature is between about 100 degrees centigrade and about 200 degrees centigrade; Y (e) cooling the mixture produced.
12. 12. A film comprising a mixture which comprises an emulsion and one or more water-dispersible and / or water-soluble polymer resins wherein the emulsion particles are distributed through the polymer matrix and the water in the emulsion forms hydrogen bonds with polymer molecules.
13. 13. The film as claimed in clause 12 characterized in that it has a thickness of about 1 thousandth of an inch to about 4 thousandths of an inch.
14. 14. The film as claimed in clause 12 characterized in that the emulsion comprises a polymer or copolymer selected from the group consisting of styrene butadienes, acrylics, styrene acrylics, polyvinyl * - - - and - - acetate, acrylonitrile-butadiene styrenes, acrylonitrile, 3, and acrylonitrile butadiene. - *,
15. 15. The film as claimed in clause 12 characterized in that the emulsion comprises; a styrene butadiene copolymer or an acrylonitrile butadiene copolymer.
16. 16. The film as claimed in clause 12 characterized in that the polymer resin is selected from the group consisting of polyethylene oxide (PEO), hydroxypropyl cellulose, polyvinyl alcohol (PVA), polyethyloxazoline, polyvinyl pyrrolidone, polyvinyl pyridine, gelatinized starch, nylon copolymers, polyacrylic acid, polyesters, and mixtures thereof.
17. 17. The film as claimed in clause 16 characterized in that the polymer resin is a polyethylene oxide (PEO) resin.
18. 18. A process for producing a film comprising a mixture comprising an emulsion and one or more polymer resins soluble in water and / or dispersible in water and comprising the steps of: (a) supplying pellets comprising the mixture inside an extruder which has a slot matrix; (b) heating and extruding the pellets at a temperature of about 80 degrees centigrade to about 150 degrees centigrade; Y (c) collecting the film on a cooled coiling roll.
19. 19. The process as claimed in clause 18 characterized in that the polymer resin is selected from the group consisting of polyethylene oxide (PEO), hydroxypropyl cellulose, polyvinyl alcohol (EVA), polyethyloxazoline, polyvinyl pyrrolidone, polyvinyl pyridine, gelatinized starch , nylon copolymers, polyacrylic acid, polyesters, and mixtures thereof.
20. 20. The process as claimed in clause 18 characterized in that the polymer resin is a polyethylene oxide (PEO) resin.
21. 21. The process as claimed in clause 18 characterized in that the emulsion comprises a polymer or copolymer selected from the group consisting of styrene butadienes, acrylics, styrene acrylics, polyvinyl f '' 69 acetate, styrene acyl-tributyl-butadiene, acrylonitriles, and acrylonitrile butadienes. R E S, U I N E The invention relates to mixtures of a polyethylene oxide (PEO) resin and a latex emulsion. The mixtures are formed by mixing or coating the polyethylene oxide powder resin with a latex emulsion and clarifying with the powder. The blends have an improved processability and flexibility which are beneficial in the manufacture of fibers and films based on polyethylene oxide. The composite films of the polyethylene oxide / latex blend have improved flexibility, breathability and tear resistance and are useful for the manufacture of disposable medical and personal care products that can be discarded with water discharge, such as diapers, plugs, towels for women and bladder control pads.