CA2153818A1 - Water-dispersible thermoplastic composition and articles thereof - Google Patents
Water-dispersible thermoplastic composition and articles thereofInfo
- Publication number
- CA2153818A1 CA2153818A1 CA 2153818 CA2153818A CA2153818A1 CA 2153818 A1 CA2153818 A1 CA 2153818A1 CA 2153818 CA2153818 CA 2153818 CA 2153818 A CA2153818 A CA 2153818A CA 2153818 A1 CA2153818 A1 CA 2153818A1
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- Canada
- Prior art keywords
- polyethylene
- weight percent
- thermoplastic
- composition
- daltons
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/42—Use of materials characterised by their function or physical properties
- A61L15/62—Compostable, hydrosoluble or hydrodegradable materials
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/20—Tampons, e.g. catamenial tampons; Accessories therefor
- A61F13/26—Means for inserting tampons, i.e. applicators
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
- C08L71/02—Polyalkylene oxides
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- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Epidemiology (AREA)
- Veterinary Medicine (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- Engineering & Computer Science (AREA)
- Hematology (AREA)
- Vascular Medicine (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Absorbent Articles And Supports Therefor (AREA)
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
- ~1538~
PATENT
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.
BACKGROUND 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.
~1~3~8 .
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 is 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 env;ronment 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-dispersibility have been to use a synthetic material that will soften and swell when contacted with water, such as polyvinyl alcohol. However, it 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 21~3~
-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. Thewall thickness of the tampons using this composition typically ranges from about0.40 to about 1.19 millimeters.
Another approach in the pL~aldlion 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 alcoholpolymers 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 0.70millimeters 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 is stable for storage and use, is water dispersible, and is capable of being formed into flexible thin walled devices such as tampon applicators.
SUl\~ ARY 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 atampon applicator, can be formed.
The present invention provides 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 ~ 3~ ~
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-methacrylate, or polystyrene-co-methyl methacrylate, and mixtures thereof.
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-vinyl 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.
The present invention provides a thermoplastic composition that is water-dispersible. More specif1cally, the invention provides a tampon insertion devicethat can be disposed of through conventional toilet facilities.
The invention also provides a thermoplastic composition suitable for forming a water-dispersible tampon insertion device via injection molding or extrusion having a shape and design suitable for convenience and comfort in feminine care applications.
Further, the invention provides a water-dispersible thermoplastic tampon insertion device which is stable in dimension and material for long term storageperiods in high humidity conditions, as are expected in bathroom environments.
The invention also provides 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.
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. Inpreferred embodiments, the tampon applicator of the present invention comprises a -215~81~
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 difi~erent, but mostpreferably, the tubes will have a mating relationship with a common - 4a-- 215~
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 in 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 PolYmer Science and Engineerinq Volume 8, John Wiley and Sons, New York, 1987, pp. 102-138. For a general discussion of extrusion, see Richardson "Plastics Processing", EncYcloPedia of PolYmer 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 22-23C water, they begin to soften and dissolve in a short time, and in due course, disperse completely.
~ ~ ~15~
Looking at some of the components in greater detail, a compounded polymer formulation found to have excellent moldable and extrudable properties is 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 is available from Union Carbide Corporation, located at 39 Old Ridgebury Road, Danbury, Connecticut and is sold under the tradename POLYOX0. 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 acid, 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 is 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 in 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'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)] bisoxirane, 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 is TERGITOL NP-33 which is 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 is 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 215~8~
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 (POLYOX~ WSR-N-80, available from Union Carbide Corporation), about 15% by weight of linear low density polyethylene (DOWLEX 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 185~ psi Holding pressure 309 psi Hold time 2.0 sec Injection speed 5.08 cm/sec Cool time 12.0 sec 21~818 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 23C tap water without agitation in less than two hours.
Exam~le II
A polymer blend was prepared from a mixture of about 84% by weight of polyethylene oxide (poLyoxx WSR-N-80, available from Union Carbide Corporation), about 15% by weight of nylon 11 (available from Elf Atochem 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:
g 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.
Exam~le III
Polymer blends were prepared from mixtures of polyethylene oxide (POLYOX~ WSR-N-80, available from Union Carbide), polyethylene-co-vinyl alcohol (ES-GllOA, 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 (TERGITOL0 NP-13, available from Union Carbide). The compositions are listed in Table I as components based on percent by weight.
Table I
C1 Blend C2 Blend POLYOX~ WSR-N-80 84.25 84.25 E~ALCA ES-GllOA 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 C1 blend was then molded in an Engel Model ES80 injection molding machine using a 35 mm diameter screw with the following conditions:
C1 Blend C2 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) 2 1~3~ ~8 -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 C1 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 C1 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 23C tap water without agitation in less than two hours.
Example IV
A polymer blend was prepared from a mixture of about 77YO by weight of polyethylene oxide (POLYOX0 WSR-N-80, available from Union Carbide Corporation), about 14% by weight of polyethylene-co-acrylic acid (PRIMACOR0 3460, available from The Dow Chemical Company located in Midland, Michigan), about 8% by weight of polysorbate ester (TWEEN0 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:
~1538~8 Temperatures (F):
Nozzle 370 Zone 2 'front) 351 Zone 3 center) 337 Zone 4 rear) 311 Man i fol d 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 23C tap water without agitation in less than two hours.
Example V
A polymer blend was prepared from a mixture of about 85Yo by weight of polyethylene oxide (POLYOX~ WSR-N-10~ available from Union Carbide Corporation) and about 15% by weight of polyethylene-co-30 vinyl alcohol (ES-GllOA, 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 2~53818 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.
Exam~le 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 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.
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 38~
-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 acid mixture (SPECTRATECH FM 1570 H
available from Quantum Chemical Corporation located in Cincinnati, Ohio).
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:
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.
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 ~1~3818 density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in 23-C tap water without agitation in less than two hours.
Having thus described the invention, numerous changes and ~odifications thereof will be readily apparent to those having ordinary skill in the art without departing from the spirit and scope of the invention.
PATENT
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.
BACKGROUND 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.
~1~3~8 .
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 is 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 env;ronment 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-dispersibility have been to use a synthetic material that will soften and swell when contacted with water, such as polyvinyl alcohol. However, it 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 21~3~
-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. Thewall thickness of the tampons using this composition typically ranges from about0.40 to about 1.19 millimeters.
Another approach in the pL~aldlion 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 alcoholpolymers 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 0.70millimeters 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 is stable for storage and use, is water dispersible, and is capable of being formed into flexible thin walled devices such as tampon applicators.
SUl\~ ARY 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 atampon applicator, can be formed.
The present invention provides 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 ~ 3~ ~
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-methacrylate, or polystyrene-co-methyl methacrylate, and mixtures thereof.
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-vinyl 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.
The present invention provides a thermoplastic composition that is water-dispersible. More specif1cally, the invention provides a tampon insertion devicethat can be disposed of through conventional toilet facilities.
The invention also provides a thermoplastic composition suitable for forming a water-dispersible tampon insertion device via injection molding or extrusion having a shape and design suitable for convenience and comfort in feminine care applications.
Further, the invention provides a water-dispersible thermoplastic tampon insertion device which is stable in dimension and material for long term storageperiods in high humidity conditions, as are expected in bathroom environments.
The invention also provides 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.
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. Inpreferred embodiments, the tampon applicator of the present invention comprises a -215~81~
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 difi~erent, but mostpreferably, the tubes will have a mating relationship with a common - 4a-- 215~
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 in 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 PolYmer Science and Engineerinq Volume 8, John Wiley and Sons, New York, 1987, pp. 102-138. For a general discussion of extrusion, see Richardson "Plastics Processing", EncYcloPedia of PolYmer 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 22-23C water, they begin to soften and dissolve in a short time, and in due course, disperse completely.
~ ~ ~15~
Looking at some of the components in greater detail, a compounded polymer formulation found to have excellent moldable and extrudable properties is 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 is available from Union Carbide Corporation, located at 39 Old Ridgebury Road, Danbury, Connecticut and is sold under the tradename POLYOX0. 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 acid, 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 is 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 in 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'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)] bisoxirane, 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 is TERGITOL NP-33 which is 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 is 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 215~8~
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 (POLYOX~ WSR-N-80, available from Union Carbide Corporation), about 15% by weight of linear low density polyethylene (DOWLEX 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 185~ psi Holding pressure 309 psi Hold time 2.0 sec Injection speed 5.08 cm/sec Cool time 12.0 sec 21~818 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 23C tap water without agitation in less than two hours.
Exam~le II
A polymer blend was prepared from a mixture of about 84% by weight of polyethylene oxide (poLyoxx WSR-N-80, available from Union Carbide Corporation), about 15% by weight of nylon 11 (available from Elf Atochem 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:
g 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.
Exam~le III
Polymer blends were prepared from mixtures of polyethylene oxide (POLYOX~ WSR-N-80, available from Union Carbide), polyethylene-co-vinyl alcohol (ES-GllOA, 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 (TERGITOL0 NP-13, available from Union Carbide). The compositions are listed in Table I as components based on percent by weight.
Table I
C1 Blend C2 Blend POLYOX~ WSR-N-80 84.25 84.25 E~ALCA ES-GllOA 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 C1 blend was then molded in an Engel Model ES80 injection molding machine using a 35 mm diameter screw with the following conditions:
C1 Blend C2 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) 2 1~3~ ~8 -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 C1 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 C1 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 23C tap water without agitation in less than two hours.
Example IV
A polymer blend was prepared from a mixture of about 77YO by weight of polyethylene oxide (POLYOX0 WSR-N-80, available from Union Carbide Corporation), about 14% by weight of polyethylene-co-acrylic acid (PRIMACOR0 3460, available from The Dow Chemical Company located in Midland, Michigan), about 8% by weight of polysorbate ester (TWEEN0 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:
~1538~8 Temperatures (F):
Nozzle 370 Zone 2 'front) 351 Zone 3 center) 337 Zone 4 rear) 311 Man i fol d 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 23C tap water without agitation in less than two hours.
Example V
A polymer blend was prepared from a mixture of about 85Yo by weight of polyethylene oxide (POLYOX~ WSR-N-10~ available from Union Carbide Corporation) and about 15% by weight of polyethylene-co-30 vinyl alcohol (ES-GllOA, 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 2~53818 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.
Exam~le 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 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.
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 38~
-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 acid mixture (SPECTRATECH FM 1570 H
available from Quantum Chemical Corporation located in Cincinnati, Ohio).
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:
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.
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 ~1~3818 density polyethylene, and non-tacky surface. The tampon applicator tubes dispersed in 23-C tap water without agitation in less than two hours.
Having thus described the invention, numerous changes and ~odifications thereof will be readily apparent to those having ordinary skill in the art without departing from the spirit and scope of the invention.
Claims (21)
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.
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. The composition of claim 1, 2, 3, 4, 5 or 6 which is water-dispersible.
8. 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 acid, polyethylene-co-acrylic acid, polystyrene, polymethyl methacrylate, or polystyrene-co-methyl methacrylate and mixtures thereof; and c) an effective amount of a suitable foaming agent.
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 acid, polyethylene-co-acrylic acid, polystyrene, polymethyl methacrylate, or polystyrene-co-methyl methacrylate and mixtures thereof; and c) an effective amount of a suitable foaming agent.
9. The device of claim 8 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 is sodium bicarbonate/citric acid mixtures, azodicarbonamide compounds, sodium borohydride or 5-phenlytetrazole.
10. The device of claim 8 wherein said polyethylene oxide polymer comprises from about 80 to about 95 weight percent of said thermoplastic composition.
11. The device of claim 8 further including a non-ionic surfactant.
12. The device of claim 11 wherein said surfactant is selected from the group consisting of polysorbate ester and nonylphenyl polyethylene glycol.
13. The device of claim 12 wherein said surfactant comprises less than about 2 weight percent of said composition.
14. The device of claim 8 wherein said thermoplastic component is polyethylene-co-vinyl alcohol.
15. 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.
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.
16. The thermoplastic tampon applicator of claim 15 wherein said foaming agent is a sodium bicarbonate/citric acid mixture.
17. The thermoplastic tampon applicator of claim 15 wherein said polyethylene oxide polymer comprises from about 80 to about 95 weight percent of said thermoplastic composition.
18. The thermoplastic tampon applicator of claim 15 further including a non-ionic surfactant.
19. The thermoplastic tampon applicator of claim 18 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.
20. The thermoplastic tampon applicator of claim 15 wherein said thermoplastic component is polyethylene-co-vinyl alcohol.
21. The thermoplastic tampon applicator of claim 15 wherein said molecular weight of said polyethylene oxide groups ranges from about 100,000 daltons to about 500,000 daltons.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US28608794A | 1994-08-03 | 1994-08-03 | |
| US286,087 | 1994-08-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2153818A1 true CA2153818A1 (en) | 1996-02-04 |
Family
ID=23097016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2153818 Abandoned CA2153818A1 (en) | 1994-08-03 | 1995-07-13 | Water-dispersible thermoplastic composition and articles thereof |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU3129595A (en) |
| CA (1) | CA2153818A1 (en) |
| FR (1) | FR2723744A1 (en) |
| WO (1) | WO1996004338A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9192522B2 (en) | 2003-05-02 | 2015-11-24 | Eveready Battery Company, Inc. | Tampon assembly having shaped pledget |
| US9662249B2 (en) | 2002-09-12 | 2017-05-30 | Edgewell Personal Care Brands, Llc. | Ergonomic tampon applicator |
| US9820890B2 (en) | 2006-06-12 | 2017-11-21 | Edgewell Personal Care Brands, Llc. | Tampon assembly providing proper bodily placement of pledget |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999033920A1 (en) * | 1997-12-31 | 1999-07-08 | Kimberly-Clark Worldwide, Inc. | Flushable poly(ethylene oxide) films with balanced mechanical properties |
| EP1368069B1 (en) * | 2001-03-16 | 2009-12-09 | The Procter & Gamble Company | Flushable tampon applicators |
| US6730057B2 (en) | 2001-03-16 | 2004-05-04 | The Procter & Gamble Company | Flushable tampon applicators |
| US6515075B1 (en) * | 2001-07-12 | 2003-02-04 | Kimberly-Clark Worldwide, Inc. | Films, fibers and articles of chemically modified polyethylene oxide compositions with improved environmental stability and method of making same |
| US6509419B1 (en) * | 2001-07-12 | 2003-01-21 | Kimberly-Clark Worldwide, Inc. | Chemically modified polyethylene oxide compositions with improved environmental stability |
| US9339580B2 (en) | 2013-11-27 | 2016-05-17 | Kimberly-Clark Worldwide, Inc. | Flushable tampon applicator |
| US9456931B2 (en) | 2013-11-27 | 2016-10-04 | Kimberly-Clark Worldwide, Inc. | Thermoplastic and water-dispersible injection moldable materials and articles |
| US9320656B2 (en) | 2013-11-27 | 2016-04-26 | Kimberly-Clark Worldwide, Inc. | Water-dispersible thermoplastic injection molded composition |
| CN109923172A (en) | 2016-11-30 | 2019-06-21 | 金伯利-克拉克环球有限公司 | Material that is thermoplastic injection-molded and can breaking up |
| KR102421382B1 (en) | 2016-11-30 | 2022-07-18 | 킴벌리-클라크 월드와이드, 인크. | Thermoplastic injection molded and flushable tampon applicators |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA944689A (en) * | 1970-07-28 | 1974-04-02 | Claude Rene | Capsules en matieres plastiques et leurs procedes de fabrication |
| US4372311A (en) * | 1980-09-12 | 1983-02-08 | Union Carbide Corporation | Disposable articles coated with degradable water insoluble polymers |
| US5002526A (en) * | 1989-12-22 | 1991-03-26 | Kimberly-Clark Corporation | Tampon applicator |
| CA2065966A1 (en) * | 1991-04-23 | 1992-10-24 | Robert J. Petcavich | Disposable recyclable plastic articles and moldable synthetic resin blends for making the same |
| AU666592B2 (en) * | 1991-04-23 | 1996-02-15 | Robert J. Petcavich | Disposable degradable recyclable plastic articles and synthetic resin blends for making the same |
| US5389068A (en) * | 1992-09-01 | 1995-02-14 | Kimberly-Clark Corporation | Tampon applicator |
-
1995
- 1995-07-13 CA CA 2153818 patent/CA2153818A1/en not_active Abandoned
- 1995-07-14 AU AU31295/95A patent/AU3129595A/en not_active Abandoned
- 1995-07-14 WO PCT/US1995/008897 patent/WO1996004338A1/en active Application Filing
- 1995-08-02 FR FR9509408A patent/FR2723744A1/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9662249B2 (en) | 2002-09-12 | 2017-05-30 | Edgewell Personal Care Brands, Llc. | Ergonomic tampon applicator |
| US9737443B2 (en) | 2002-09-12 | 2017-08-22 | Edgewell Personal Care Brands, Llc | Ergonomic tampon applicator |
| US9192522B2 (en) | 2003-05-02 | 2015-11-24 | Eveready Battery Company, Inc. | Tampon assembly having shaped pledget |
| US10105266B2 (en) | 2003-05-02 | 2018-10-23 | Edgewell Personal Care Brands, Llc. | Tampon assembly having a shaped pledget |
| US10105267B2 (en) | 2003-05-02 | 2018-10-23 | Edgewell Personal Care Brands, LLC> | Tampon assembly having a shaped pledget |
| US10383776B2 (en) | 2003-05-02 | 2019-08-20 | Edgewell Personal Care Brands, Llc | Tampon assembly having a shaped pledget |
| US9820890B2 (en) | 2006-06-12 | 2017-11-21 | Edgewell Personal Care Brands, Llc. | Tampon assembly providing proper bodily placement of pledget |
| US10575994B2 (en) | 2006-06-12 | 2020-03-03 | Edgewell Personal Care Brands, Llc | Tampon assembly providing proper bodily placement of pledget |
| US11564850B2 (en) | 2006-06-12 | 2023-01-31 | Edgewell Personal Care Brands, Llc | Tampon assembly providing proper bodily placement of a pledget |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1996004338A1 (en) | 1996-02-15 |
| FR2723744A1 (en) | 1996-02-23 |
| AU3129595A (en) | 1996-03-04 |
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