WO1996004338A1

WO1996004338A1 - Water-dispersible thermoplastic composition and articles thereof

Info

Publication number: WO1996004338A1
Application number: PCT/US1995/008897
Authority: WO
Inventors: Debra Hartley Durrance; Laura Elizabeth Keck; Robert John Petcavich
Original assignee: Kimberly-Clark Worldwide, Inc.
Priority date: 1994-08-03
Filing date: 1995-07-14
Publication date: 1996-02-15
Also published as: FR2723744A1; AU3129595A; CA2153818A1

Abstract

A water-dispersible thermoplastic composition is disclosed which can be thermoformed into a variety of thin walled devices, such as tampon insertion devices and the like. The composition includes at least about 75 weight percent polyethylene oxide having a molecular weight from about 100,000 daltons to about 3 million daltons, and a synthetic thermoplastic component.

Description

WATER-DISPERSIBLE THERMOPLASTIC COMPOSITION AND ARTICLES THEREOF

FIELD OF THE INVENTION The present invention relates to a water-dispersible, thermoplastic composition that can be used in the preparation of thin walled devices. Particularly, the invention relates to a water-dispersible composition that includes at least about 75 weight percent polyethylene oxide and a synthetic thermoplastic component. More particularly, the invention relates to tampon insertion devices and the like wherein at least a portion of the device is water-dispersible and formed from the composition.

βAC GRQMNP OF THE INVENTION Generally, in the formation of thermoplastic devices, appropriate materials are selected from compounds that typically exhibit desirable qualities for the finished product and are compatible during thermoforming. Typical techniques known in the art for thermoforming thermoplastics include injection molding and extrusion. Typically, thermoplastic devices must be disposed of in an appropriate manner where the materials may either be recycled, destroyed, or disposed of in any number of other suitable means which will not cause environmental problems.

A chronic problem generally associated with small thermoplastic devices is that they are disposed in ways which allow the devices to become environmental nuisances. For example, tampon insertion devices of the tube type are often disposed of by dropping the applicators into a toilet bowl. The standard construction for a tampon applicator is a pair of telescoping tubes, the outer tube carrying the tampon's absorbent material, commonly referred to as a pledget, and the inner tube serving as a plunger for dispensing the pledget. Tampon applicators in current commercial use are typically made from either a plastic or paper-based material. Plastic tampon applicators are preferred by some women since they can be molded to include a grip ring in a petal-shaped forward end, which aids in the Insertion of the device and in retaining and protecting the pledget while it 1s in the outer tube.

Plastic tampon applicators are typically made from polyethylene using an injection molding process. However, such tubes suffer from a disadvantage in that the thermoplastic materials used are not water soluble and therefore will not disintegrate or degrade when disposed of in a toilet system. While such applicators flush, they pass through treatment systems without decomposing. The stable nature of the applicators also permits them to accumulate in wastewater treatment plants, blocking the screens and impeding the treatment of other wastes. If the tampon applicators are not removed via the screens they escape into the environment intact, often washing up on the beaches. In view of such environmental and aesthetic considerations, it is highly desirable that plastic applicators be water dispersible or biodegradable. Such properties have not yet been achieved commercially, in spite of efforts to achieve these properties for a plastic-based material.

Early attempts to overcome the problem of water-dispers1b1l1ty have been to use a synthetic material that will soften and swell when contacted with water, such as polyvinyl alcohol. However, 1t has been discovered that polyvinyl alcohol is unworkable in a commercial environment because the polyvinyl alcohol becomes unstable in the presence of moisture-laden air. The composition becomes tacky and loses structural stability when in contact with moist surfaces. Another approach has been to use a thermoplastic, normally water-soluble polymer, compounded with low cost clays, talc, wood flour, fibers, and the like, which Is then extruded or molded to obtain the desired shape and configuration of the device. The water-soluble polymer includes polyethylene oxide polymers having a molecular weight of from about 100,000 to about 2,000,000 and hydroxypropyl cellulose polymers with a molecular weight of about 75,000 to about 375,000. The wall thickness of the tampons using this composition typically ranges from about 0.40 to about 1.19 millimeters.

Another approach in the preparation of tampon applicators has been to use different water-soluble polymers to produce the Inner and outer tubes. In this way, problems with the tubes fusing together under high humidity/high temperature conditions are avoided. Other solutions Include using modified polyvinyl alcohol polymers or polyvinyl alcohol polymers coated with a water-Insoluble, but biodegradable polymer, such as polycaprolactone.

Although the above compositions may be sufficient for forming tampon applicators and other devices having fairly thick walls, I.e., greater than 0.70 millimeters it has been found that they are unsuitable for forming flexible, thin walled tampon applicators and other devices which would have a wall thickness ranging from about 0.15 millimeters to about 0.60 millimeters.

Therefore, there exists a need for a thermoplastic composition that 1s stable for storage and use, is water dispersible, and Is capable of being formed into flexible thin walled devices such as tampon applicators.

SUMMARY OF THE INVENTION Briefly, the present invention provides for a thermoplastic composition that is capable of being thermoformed Into a variety of thermoplastic devices and is especially effective in producing flexible thermoplastic devices having a wall thickness of less than about 0.60 millimeters. The thermoplastic devices can be formed by either Injection molding or extrusion. Advantageously, the devices formed from the thermoplastic composition are water-dispersible. In one aspect of the present invention, thin walled articles, such as the various components of a tampon applicator, can be formed. The water-dispersible, thermoplastic composition includes at least about 75 weight percent of a water-dispersible polymer composed of polyethylene oxide groups and about 25 weight percent of a synthetic thermoplastic component selected from polycaprolactone, polyethylene-co-vinyl alcohol, Nylon 11, Nylon 12, polyvinyl acetate, polyethylene-co-v1nyl acetate, polyvinyl chloride, polyethylene-co-methacrylic acid, polyethylene-co-acrylic acid, polystyrene, polymethyl methacrylate, polystyrene-co-methyl methacrylate and mixtures thereof. Preferably, the water-dispersible thermoplastic composition has a melt flow index ranging from about 1 to about 150. The water-dispersible composition can also include lubricants and up to about 2 weight percent of a non-ionic surfactant. It is a general object of the invention to provide a thermoplastic composition that is water-dispersible. A more specific object of the invention is to provide a tampon insertion device that can be disposed of through conventional toilet facilities.

It is another object of the invention to provide a thermoplastic composition suitable for forming a water-dispersible tampon insertion devices via injection molding or extrusion having a shape and design suitable for convenience and comfort in feminine care applications.

It is yet another object of the invention to provide a water-dispersible thermoplastic tampon insertion device which are stable in dimension and material for long term storage periods 1n high humidity conditions, as expected in bathroom environments.

Another object of the invention is to provide a water-dispersible, thermoplastic composition that is capable of being molded or extruded into a device having a wall thickness of less than about 0.70 millimeters.

Other objects and advantages of the present Invention will become more apparent to those skilled in the art in view of the following description.

DETAILED DESCRIPTION OF THE INVENTION

By way of example, a typical tampon applicator formed from the composition of this invention may comprise a single elongated tubular member. In preferred embodiments, the tampon applicator of the present invention comprises a pair of telescoping tubes, either or both of which can be straight or curved. If both tubes are curved, the radii of curvature can be the same or different, but most preferably, the tubes will have a mating relationship with a common radius of curvature. The tubes can be prepared by injection molding, profile extrusion, or by utilizing both methods in combination. If both Injection molding and profile extrusion are employed, the outer tube typically can be made by injection molding, whereas the inner tube can be made by profile extrusion. Typically, a tampon applicator incorporating the invention may comprise an outer tube that is approximately 6-7.5 centimeters (cm) long and about 1.27 cm in diameter and having a wall thickness of about 0.35 millimeters. The inner tube can have a similar length and wall thickness, but with an outer diameter slightly less than 1.27 cm. Tube elements of approximately the above dimensions may be fabricated in the simplest form by injection molding of water-dispersible compounded plastic having the following formula:

At least about 75 percent polyethylene oxide polymer having a molecular weight ranging from about 100,000 daltons to about 3,000,000 daltons and about 25 to about 5 weight percent of a synthetic thermoplastic component polymer or copolymer that has a suitable degree of compatibility with polyethylene oxide.

The molding or extrusion of the thermoplastic composition can be performed using conventional equipment 1n accordance with well-known procedures. The specific process and conditions employed will, of course, depend on the specifics of the equipment and the molds or dies used. For a general discussion of injection molding, see Ruben, "Injection Molding", Encyclopedia of Polvmer Science and Engineering Volume 8, John Wiley and Sons, New York, 1987, pp. 102-138. For a general discussion of extrusion, see Richardson "Plastics Processing", Encyclopedia of Polvmer Science and Engineering. Volume 11, John Wiley and Sons, New York, 1988, pp 262-285. The resulting tampon tubes have a smooth outer surface with walls which are sufficiently rigid to resist denting. The tampon tubes have a resilience which permits a reasonable amount of distortion or bending without causing permanent deformation. When these tampon tubes are dropped Into 500 ml of 22-23'C water, they begin to soften and dissolve in a short time, and in due course, disperse completely. Looking at some of the components in greater detail, a compounded polymer formulation found to have excellent moldable and extrudable properties 1s composed of at least about 75 weight percent of polyethylene oxide and preferably about 80-95 weight percent polyethylene oxide and about 25-5 weight percent of a synthetic thermoplastic component. The polyethylene oxide can have a molecular weight ranging from about 100,000 daltons to about 3 million daltons. Polyethylene oxide 1s available from Union Carbide Corporation, located at 39 Old Ridgebury Road, Danbury, Connecticut and Is sold under the tradename P0LY0X*. The synthetic thermoplastic component is selected from polycaprolactone, polyethylene-co-vinyl alcohol, Nylon 11, Nylon 12, polyvinyl acetate, polyethylene-co-vinyl acetate, polyvinyl chloride, polystyrene, polyethylene-co-methacrylic add, polyethylene-co-acrylic acid, polymethyl methacrylate, or polystyrene-co-methyl methacrylate, and mixtures thereof. Preferably, the synthetic thermoplastic component is polyethylene-co-vinyl alcohol.

It is important to this invention that the amount of polyethylene oxide present in the blended composition be at least 75 weight percent. We have found that for thin wall products, i.e., less than about 0.35 millimeters formed from compositions having less than about 70 weight percent polyethylene oxide exhibit Incomplete formation and lack consistent structural integrity.

Considering that the above-mentioned formulation 1s readily extrudable or injection moldable it can be seen that, in addition to the plain tubes described earlier, tubes of various other shapes and configurations may be easily made. For example, the leading end of the outer tube may have a conical shape formed from flexible petal-like segments to provide an easy-opening, small insertion tip which facilitates Insertion as well as protecting the tampon contents prior to Insertion. Also, the ejector tube element may be made of much smaller diameter to cooperate with a small diameter collar disposed at the base of the outer tube, as is done in some current polyethylene tube designs. An Important contribution of this invention is the development of plastic tubes which provides all the desirable aesthetic and functional characteristics now found In water-insensitive, non-dispersible plastic insertion tubes, yet which may be disposed of 1n a water base sanitary system with the assurance that the tubes will disintegrate and completely disperse in due course.

The compositions above can be used alone or, preferably, with suitable additives, fillers, pigments, odor maskers, and other similar materials conventionally used in the preparation of personal care products. Examples of pigments include titanium dioxide, calcium oxide, zinc oxide, and the like. Suitable odor maskers include, among others, fragrances, calcium carbonate, sodium bicarbonate, zinc oxide, and the like.

In addition to the foregoing ingredients, relatively low levels of an external plasticizer, i.e., less than about 5 percent by weight, can be used if desired for particular applications. For example, molding of tampon applicators having a particularly complex shape may be facilitated by the presence of an external plasticizer. Lubricants such as magnesium or zinc stearate may also be used to improve the plastic flow in the molding devices. Another suitable lubricating composition is polyethylene glycol compounded with 2,2'-[(l-methylethylidene)bis(4,l-phenyleneoxymethylene)] bisoxlrane, also known by the tradename CARBOWAX* 20M, available from the Union Carbide Corporation.

The compounded polymer composition can also include from about 0.1-10 weight percent and preferably less than about 2 weight percent of a non-ionic surfactant such as nonylphenol polyglycol ether containing less than about 65 oxyethylene units. One such agent 1s TERGIT0L NP-33 which 1s also available from the Union Carbide Corporation.

The polymer composition can also include from about 0.5 weight percent to about 4 weight percent of a foam concentrate in a suitable base resin. Although not wishing to be bound by any theory, It 1s believed the foam concentrate performs a function similar to that of a diluent. That is, it allows the thermoplastic components to flow more freely Into an injection mold for part manufacture. Various foaming concentrates are suitable for use in this invention. The foaming concentrates can be selected taking Into consideration compatibilities of the mixture constituents and the desirability of the foaming agent to adequately perform under the processing conditions. Suitable foam concentrates include sodium bicarbonate/citric acid mixtures, azodicarbonamide compounds, sodium borohydride and 5-phenlytetrazole. Examples of base resins Include polyethylene (LDPE) and ethylene vinyl acetate. Foaming concentrates are available from Quantum Chemical Corporation located in

Cincinnati, Ohio under the trade name SPECTRATECH FM 1035 H and SPECTRATECH FM 1570 H.

Without intending to limit this Invention in any manner, the present Invention will now be further Illustrated by the following examples using different polymer blends.

Example I A polymer blend was prepared from a mixture of about 59% by weight of polyethylene oxide (P0LY0X* WSR-N-80, available from Union Carbide Corporation), about 15% by weight of linear low density polyethylene (DO LEX* 2503, available from The Dow Chemical Company located in Midland, Michigan, about 25% by weight of polysorbate ester (TWEEN* 20, available from Emulsion Engineering), and about 1% by weight of a proprietary phosphate ester mold release agent (MOLD WIZ #INT-33PA, available from Axel Plastics located in Woodside, New York).

The blended components were compounded using a single-screw extruder with 44.45 millimeter screw diameter manufactured by Black-Clawson at 60 rpm, at temperatures ranging from about 65^* C at the feed section to about 170^* C at the die tip.

The blend was then molded in an Engel Model ES80 injection molding machine using a 35 mm diameter screw with the following conditions:

Temperatures (°F):

Nozzle 368

Zone 2 (front) 351

Zone 3 (center) 328

Zone 4 (rear) 315

Manifold 420

Hot tips 360

Mold 80 (core)

90 (cavity)

Injection pressure 1856 psi

Holding pressure 309 psi

Hold time 2.0 sec

Injection speed 5.08 cm sec

Cool time 12.0 sec The material was observed to fill less than one half of the volume of the mold cavity. The partial tampon applicator tubes molded from the material were observed to have the following characteristics: opaque, off-white color; flexibility and resilience approximate to linear low density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in 23^*C tap water without agitation in less than two hours.

Example II A polymer blend was prepared from a mixture of about 84% by weight of polyethylene oxide (POLYOX* WSR-N-80, available from Union Carbide Corporation), about 15% by weight of nylon 11 (available from Elf Atoche Polymers), and about 1% by weight of a proprietary phosphate ester mold release agent (MOLD WIZ #INT-33PA, available from Axel Plastics).

The blended components were compounded using a single-screw extruder with 44.45 millimeter screw diameter manufactured by

Black-Clawson at 60 rpm, at temperatures ranging from about 65* C at the feed section to about 170^* C at the die tip.

The blend was then extruded through a 1-inch diameter Killion extruder with a tubing profile die and take-off system to produce small-diameter tubing pieces produced and cut to length continuously. The following extrusion conditions were used: Temperatures (°F):

Zone 1 (rear) 231

Zone 2 (center) 272

Zone 3 (rear) 280

Die 1 286

Die 2 286

Die 3 270

Melt 301

Screw speed 16.5 rpm

Back pressure 5000-5500 psi

Drive amps 6-7

The material was observed to exhibit Inadequate strength for continuous profile extrusion. Short lengths of tubing produced in this manner were observed to have the following characteristics: opaque, off-white color; stiffness comparable to high density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in tap water without agitation In less than two hours.

Example III Polymer blends were prepared from mixtures of polyethylene oxide (P0LY0X» WSR-N-80, available from Union Carbide), polyethylene- co-vinyl alcohol (ES-G110A, available from EVAL Company of America located in Lisle, Illinois), and an additive of less than 2% of a polysorbate ester (TWEEN 20, available from Emulsion Engineering located in Sanford, Florida) or a nonylphenol polyethylene glycol ether (TERGITOL* NP-13, available from Union Carbide). The compositions are listed in Table I as components based on percent by weight.

Table I Cl Blend C2 Blend

POLYOX" WSR-N-80 84.25 84.25 EVALCA ES-G110A 14.25 14.25 TWEEN** 20 0.50 0 TERGITOL* NP-13 0 0.50

The blended components were compounded using a single-screw extruder with 44.45 millimeters screw diameter manufactured by Black-Clawson at 60 revolutions per minute (rpm), at temperatures ranging from about 65* C at the feed section to about 170* C at the die tip.

The Cl blend was then molded in an Engel Model ES80 injection molding machine using a 35 mm diameter screw with the following conditions:

Cl Blend 2 Blend

Temperatures (°F):

Nozzle 317 339

Zone 2 (front) 350 341

Zone 3 (center) 332 328

Zone 4 (rear) 308 315

Manifold 420 420

Hot tips 312, 360 360

Mold 80 (core) 80 (core)

90 (cavity) 90 (cavity) Injection pressure 1856 psi 1856 psi Holding pressure 461 psi 816 psi Hold time 1.6 sec 1.6 sec Injection speed 2.54 cm/sec 2.54 cm/sec Cool time 12.0 sec 20.0 sec

The materials of Cl and C2 were observed to exhibit similar molding characteristics, but with longer cooling times, as measured by comparison to polyethylene. The temperatures of Example 1 were observed to be too low, as Indicated by the presence of visible knit lines in most of the tampon applicator tubes produced under these conditions.

The Injection molded tampon applicator tubes molded from the materials of Cl and C2 were observed to have the following characteristics: translucent, off-white color; flexibility and resilience approximate to linear low density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in 23*C tap water without agitation in less than two hours.

Example IV A polymer blend was prepared from a mixture of about 77% by weight of polyethylene oxide (P0LY0X* WSR-N-80, available from Union Carbide Corporation), about 14% by weight of polyethylene-co-acryl1c acid (PRIMACOR* 3460, available from The Dow Chemical Company located in Midland, Michigan), about 8% by weight of polysorbate ester (TWEEN* 20, available from Emulsion Engineering), and about 1% by weight of a proprietary pigment concentrate blend (HOLLAND CROSS-WHITE PIGMENT, available from Holland Colors located at Richmond, Indiana).

The blended components were compounded using a single-screw extruder with 44.45 millimeter screw diameter manufactured by Black-Clawson at 60 rpm, at temperatures ranging from about 65^* C at the feed section to about 170^* C at the die tip. The blend was then molded in an Engel Model ES80 Injection molding machine using a 35 mm diameter screw with the following conditions: Temperatures (°F):

Nozzle 370

Zone 2 (front) 351

Zone 3 (center) 337

Zone 4 (rear) 311

Manifold 421

Hot tips 298

Mold 80 (core) 100 (cavity)

Injection pressure 1943 psi

Holding pressure 635 psi

Hold time 1.4 sec

Injection speed 11.18 cm/sec

Cool time 20.0 sec

The material was observed to exhibit similar molding characteristics, but with longer cooling times, as measured by comparison to polyethylene. The tampon applicator tubes molded from the material were observed to have the following characteristics: opaque, off-white color; flexibility and resilience approximate to linear low density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in 23'C tap water without agitation in less than two hours.

Example V A polymer blend was prepared from a mixture of about 85% by weight of polyethylene oxide (POLYOX* WSR-N-10, available from Union Carbide Corporation) and about 15% by weight of polyethylene-co- vinyl alcohol (ES-G110A, available from EVAL Company of America). The blended components were compounded using a single-screw extruder with 44.45 millimeter screw diameter manufactured by Black-Clawson at 60 rpm, at temperatures ranging from about 65* C at the feed section to about 170^* C at the die tip. The blend was then molded in a Van Dorn model 150-RS-8F injection molding machine.

Temperatures (*F): (Actual)

Nozzle 447

Zone 2 (front) 438 Zone 3 (center) 433

Zone 4 (center) 435

Zone 5 (rear) 433

Mold Temperature 70 Injection pressure 826 psi

Holding pressure 449 psi

Hold time 0.1 sec

Injection speed 13.97 cm/sec Cool time 22.2 sec

The material was observed to exhibit similar molding characteristics, but with longer cooling times and difficulty in part ejection, as compared to polyethylene.

The tampon applicator tubes molded from the material were observed to have the following characteristics: translucent, off-white color; flexibility and resilience approximate to linear low density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in 23^*C tap water without agitation in less than two hours.

Example VI

A polymer blend was prepared from a mixture of about 77% by weight of polyethylene oxide (POLYOX* WSR-N-80, available from Union

Carbide Corporation), about 15% by weight of polyethylene-co-acrylic acid (PRIMACOR 1321, available from The Dow Chemical Company), and about 8% by weight of polysorbate ester (TWEEN* 20, available from

Emulsion Engineering).

The blend was then molded in a Van Dorn model 150-RS-8F injection molding machine. Temperature (^*F) (Actual)

Nozzle 435

Zone 2 429

Zone 3 429

Zone 4 417 Zone 5 401

Mold Temperature 70

Injection pressure 667 psi Holding pressure 449 psi Hold time 1.5 sec

Injection speed 8.89 cm/sec Cool time 22.2 sec The material was observed to exhibit similar molding characteristics, but with longer cooling times and difficulty in part ejection, as compared to polyethylene.

Example VII

A polymer blend was prepared from a mixture of about 75% by weight of polyethylene oxide (POLYOX* WSR-N-80) about 13.7% by weight of polyethylene-co-acrylic acid (PRIMACOR* 3460), about 8.3% by weight of polysorbate ester (TWEEN* 20), about 1% by weight of a proprietary pigment concentrate blend, and about 2% by weight of sodium bicarbonate/citric add mixture (SPECTRATECH FM 1570 H available from Quantum Chemical Corporation located in Cincinnati,

Ohio).

Black-Clawson at 60 rpm, at temperatures ranging from about 65^* C at the feed section to about 170^* C at the die tip.

Temperature (^*F)

Zone 2 401

Zone 3 399

Zone 4 300 Manifold 400

Hot tips 210

Mold 30

Injection pressure 2175 psi Holding pressure 450 psi

Hold time 0.8 sec

Injection speed 11.94 cm sec

Cool time 20 sec

The material was observed to exhibit similar molding characteristics, but with longer cooling times as compared to polyethylene.

Having thus described the invention, numerous changes and modifications thereof will be readily apparent to those having ordinary skill in the art without departing from the spirit and scope of the invention.

Claims

We claim:

1. A thermoplastic composition comprising: a) at least about 75 weight percent polyethylene oxide polymer having a molecular weight ranging from about 100,000 daltons to about 3 million daltons; and b) about 25-5 weight percent of a synthetic thermoplastic component selected from polycaprolactone, polyethylene-co-vinyl alcohol, Nylon 11, Nylon 12, polyvinyl acetate, polyethylene-co- vinyl acetate, polyvinyl chloride, polyethylene-co-methacrylic acid, polyethylene-co-acrylic acid, polystyrene, polymethyl methacrylate, or polystyrene-co-methyl methacrylate, and mixtures thereof.

2. The composition of claim 1 wherein said polyethylene oxide polymer comprises from about 80 to about 95 weight percent of said composition.

3. The composition of claim 1 further including less than about 2 weight percent of a non-ionic surfactant.

4. The composition of claim 3 wherein said surfactant is selected from the group consisting of polysorbate ester and nonylphenol polyethylene glycol.

5. The composition of claim 1 further comprising from about 0.5 weight percent to about 4 weight percent of a foaming compound.

6. The composition of claim 1 wherein said thermoplastic component is polyethylene-co-vinyl alcohol.

7. A water-dispersible molded thermoplastic device having a wall thickness less than about 0.70 millimeters wherein said thermoplastic comprises a blended composition having: a) at least about 75 weight percent polyethylene oxide polymer having a molecular weight ranging from about 100,000 daltons to about 3 million daltons; b) about 25-5 weight percent of a synthetic thermoplastic component selected from polycaprolactone, polyethylene-co-vinyl alcohol, Nylon 11, Nylon 12, polyvinyl acetate, polyethylene-co-vinyl acetate, polyvinyl chloride, polyethylene-co-methacrylic add, polyethylene-co-acrylic add, polystyrene, polymethyl methacrylate, or polystyrene-co-methyl methacrylate and mixtures thereof; and c) an effective amount of a suitable foaming agent.

8. The device of claim 7 wherein said blended thermoplastic composition has from about 0.5 weight percent to about 4 weight percent of said foaming agent, wherein said foaming agent 1s sodium bicarbonate/citric acid mixtures, azodicarbonamide compounds, sodium borohydride or 5-phenlytetrazole.

9. The device of claim 7 wherein said polyethylene oxide polymer comprises from about 80 to about 95 weight percent of said thermoplastic composition.

10. The device of claim 7 further including a non-ionic surfactant.

11. The device of claim 10 wherein said surfactant is selected from the group consisting of polysorbate ester and nonylphenyl polyethylene glycol.

12. The device of claim 11 wherein said surfactant comprises less than about 2 weight percent of said composition.

13. The device of claim 7 wherein said thermoplastic component 1s polyethylene-co-vinyl alcohol.

14. A water-dispersible, thermoplastic tampon applicator having at least one elongated tubular member prepared from an injection-moldable or extrudable material comprising a) about 80-95 weight percent polyethylene oxide polymer having a molecular weight ranging from about 100,000 daltons to about 3 million daltons; b) about 20-5 weight percent of a synthetic thermoplastic component selected from polycaprolactone, polyethylene- co-vinyl alcohol, Nylon 11, Nylon 12, polyvinyl acetate, polyethylene-co-vinyl acetate, polyvinyl chloride, polyethylene-co-methacrylic acid, polyethylene-co-acrylic acid, polystyrene, polymethyl methacrylate, or polystyrene-co-methyl methacrylate and mixtures thereof; and c) about 0.5 weight percent to about 4 weight percent of a suitable foaming agent.

15. The thermoplastic tampon applicator of claim 14 wherein said foaming agent is a sodium bicarbonate/citric acid mixture.

16. The device of claim 14 wherein said polyethylene oxide polymer comprises from about 80 to about 95 weight percent of said thermoplastic composition.

17. The device of claim 14 further including a non-ionic surfactant.

18. The device of claim 17 wherein said surfactant comprises less than about 2 weight percent of said composition and is selected from the group consisting of polysorbate ester and nonylphenol polyethylene glycol.

19. The device of claim 14 wherein said thermoplastic component is polyethylene-co-vinyl alcohol.

20. The device of claim 14 wherein said molecular weight of said polyethylene oxide groups ranges from about 100,000 daltons to about 500,000 daltons.