U.S. patent application number 09/944672 was filed with the patent office on 2003-02-27 for flushable tampon applicators.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Gilbertson, Gary Wayne, Gray, Brian Francis, McAvoy, Drew Clifton, Quiram, Daniel Jonathan, Wnuk, Andrew Julian, Zhao, Jean Jianqun.
Application Number | 20030040695 09/944672 |
Document ID | / |
Family ID | 25203498 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030040695 |
Kind Code |
A1 |
Zhao, Jean Jianqun ; et
al. |
February 27, 2003 |
Flushable tampon applicators
Abstract
Disclosed are flushable tampon applicators which comprise a
combination of thermoplastic materials and filler such as calcium
carbonate and talc, and which readily disintegrate in water such as
toilet water for improved disposal and reduced environmental
concerns regarding the destruction of these applicators. The
flushable tampon applicators comprise a combination of high
molecular weight polyethylene oxides, low molecular weight
polyethylene glycols, biodegradable polymers, and filler, wherein
this combination of water-dispersible thermoplastic polymers,
biodegradable thermoplastic polymers, and filler provide flushable
tampon applicators that are readily disposed of and that are
smooth, soft, flexible, and non-sticky or non-slimy to the touch
before and during use.
Inventors: |
Zhao, Jean Jianqun;
(Cincinnati, OH) ; Gilbertson, Gary Wayne;
(Liberty Township, OH) ; Gray, Brian Francis;
(Cincinnati, CA) ; McAvoy, Drew Clifton;
(Cincinnati, OH) ; Quiram, Daniel Jonathan; (West
Chester, OH) ; Wnuk, Andrew Julian; (Wyoming,
OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Assignee: |
The Procter & Gamble
Company
|
Family ID: |
25203498 |
Appl. No.: |
09/944672 |
Filed: |
August 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09944672 |
Aug 31, 2001 |
|
|
|
09810292 |
Mar 16, 2001 |
|
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Current U.S.
Class: |
604/15 |
Current CPC
Class: |
Y10S 604/904 20130101;
A61F 13/26 20130101; A61L 15/62 20130101 |
Class at
Publication: |
604/15 |
International
Class: |
A61F 013/20 |
Claims
What is claimed is:
1. A flushable tampon applicator comprising: (a) from 0% to about
90% by weight of a water-dispersible polymer; (b) from about 10% to
about 50% by weight of a biodegradable polymer; and (c) from 0% to
about 50% by weight of a filler.
2. The flushable tampon applicator of claim 1 wherein the water
dispersible polymer is selected from the group consisting of high
molecular weight polyethylene oxides, low molecular weight
polyethylene glycols, polyethylene/polypropylene oxide copolymers,
polyethylene/polybutylene oxide copolymers
polyethylene/polypropylene glycol copolymers, thermoplastic starch
polymers, polyvinyl alcohols, partially hydrolyzed polyvinyl
alcohols, modified polyvinyl alcohols, infrared treated polyvinyl
alcohols, cross-linked polyvinyl alcohols, alkali metal sulfonate
thermoplastic polyesters, hydroxyethyl celluloses, hydroxypropyl
celluloses, methylated hydroxypropyl celluloses, polyacrylic acids,
polyaspartic acids, polymethacrylic acids, polysaccharides,
proteins, polyvinyl pyrrolidone homopolymers, polyvinyl pyrrolidone
copolymers, polyvinyl methyl ether homopolymers, polyoxazolines,
polyvinyl methyl oxazolidones, polyvinyl methyl oxazolidimones,
polyethylenimines, polyacrylamides, polyvinyl methyl ether/maleic
anhydride copolymers, water-dispersible polyurethanes,
water-dispersible sulfonate polyesters, and mixtures thereof.
3. The flushable tampon applicator of claim 2 wherein the water
dispersible polymer is selected from the group consisting of high
molecular weight polyethylene oxides having a weight average
molecular weight of from about 65,000 daltons to about 8,000,000
daltons, low molecular weight polyethylene glycols having a number
average molecular weight of from about 500 daltons to about 20,000
daltons, and mixtures thereof.
4. The flushable tampon applicator of claim 1 wherein the
biodegradable polymer is selected from the group consisting of
aliphatic polyesteramides, diacid/diol-based aliphatic polyesters,
aromatic polyesters, aliphatic/aromatic copolyesters,
polycaprolactones, polycaprolactone copolymers,
poly(3-hydroxyalkanoates), poly(3-hydroxyalkanoates) copolymers,
dialkanoyl polymers, polyvinyl acetates, polyethylene/vinyl alcohol
copolymers, lactic acid polymers, lactide polymers, glycolide
polymers, and mixtures thereof.
5. The flushable tampon applicator of claim 1 wherein the filler is
selected from the group consisting of inorganic fillers, organic
fillers, and mixtures thereof.
6. The flushable tampon applicator of claim 5 wherein the inorganic
filler is selected from the group consisting of clays, silica,
mica, wollastonite, calcium hydroxide, calcium carbonate, sodium
carbonate, magnesium carbonate, barium sulfate, magnesium sulfate,
kaolin, calcium oxide, magnesium oxide, aluminum hydroxide, talc,
titanium dioxide, and mixtures thereof.
7. The flushable tampon applicator of claim 5 wherein the organic
filler is selected from the group consisting of wood flour, walnut
shell flour, alpha cellulose floc, cellulose fibers, chitin,
chitosan powders, organosilicone powders, nylon powders, polyester
powders, polypropylene powders, starch granules, and mixtures
thereof.
8. The flushable tampon applicator of claim 1 wherein the
applicator further comprises a lubricant selected from the group
consisting of metal soaps, hydrocarbon waxes, fatty acids,
long-chain alcohols, fatty acid esters, fatty acid amides,
silicones, fluorochemicals, acrylics, and mixtures thereof.
9. The flushable tampon applicator of claim 1 wherein the
applicator further comprises a plasticizer selected from the group
consisting of glycerin, triacetin, glycerol, monostearate,
sorbitol, erythritol, glucidol, mannitol, sucrose, ethylene glycol,
propylene glycol, diethylene glycol, triethylene glycol, diethylene
glycol dibenzoate, dipropylene glycol dibenzoate, triethylene
glycol caprate-caprylate, butylene glycol, pentamethylene glycol,
hexamethylene glycol, diisobutyl adipate, oleic amide, erucic
amide, palinitic amide, dimethyl acetamide, dimethyl sulfoxide,
methyl pyrrolidone, tetramethylene sulfone, oxa monoacids, oxa
diacids, polyoxa diacids, diglycolic acids, triethyl citrate,
acetyl triethyl citrate, tri-n-butyl citrate, acetyl tri-n-butyl
citrate, acetyl tri-n-hexyl citrate, alkyl lactates, phthalate
polyesters, adipate polyesters, glutate polyesters, diisononyl
phthalate, diisodecyl phthalate, dihexyl phthalate, alkyl alylether
diester adipate, dibutoxyethoxyethyl adipate, and mixtures
thereof.
10. A thermoplastic composite comprising: (a) from 0% to about 90%
by weight of a water-dispersible polymer; (b) from about 10% to
about 50% by weight of a biodegradable polymer; and (c) from 0% to
about 50% by weight of a filler.
11. The thermoplastic composite of claim 10 wherein the water
dispersible polymer is selected from the group consisting of high
molecular weight polyethylene oxides, low molecular weight
polyethylene glycols, polyethylene/polypropylene oxide copolymers,
polyethylene/polybutylene oxide copolymers
polyethylene/polypropylene glycol copolymers, thermoplastic starch
polymers, polyvinyl alcohols, partially hydrolyzed polyvinyl
alcohols, modified polyvinyl alcohols, infrared treated polyvinyl
alcohols, cross-linked polyvinyl alcohols, alkali metal sulfonate
thermoplastic polyesters, hydroxyethyl celluloses, hydroxypropyl
celluloses, methylated hydroxypropyl celluloses, polyacrylic acids,
polyaspartic acids, polymethacrylic acids, polysaccharides,
proteins, polyvinyl pyrrolidone homopolymers, polyvinyl pyrrolidone
copolymers, polyvinyl methyl ether homopolymers, polyoxazolines,
polyvinyl methyl oxazolidones, polyvinyl methyl oxazolidimones,
polyethylenimines, polyacrylamides, polyvinyl methyl ether/maleic
anhydride copolymers, water-dispersible polyurethanes,
water-dispersible sulfonate polyesters, and mixtures thereof.
12. The thermoplastic composite of claim 11 wherein the water
dispersible polymer is selected from the group consisting of high
molecular weight polyethylene oxides having a weight average
molecular weight of from about 65,000 daltons to about 8,000,000
daltons, low molecular weight polyethylene glycols having a number
average molecular weight of from about 500 daltons to about 20,000
daltons, and mixtures thereof.
13. The thermoplastic composite of claim 10 wherein the
biodegradable polymer is selected from the group consisting of
aliphatic polyesteramides, diacid/diol-based aliphatic polyesters,
aromatic polyesters, aliphatic/aromatic copolyesters,
polycaprolactones, polycaprolactone copolymers,
poly(3-hydroxyalkanoates), poly(3-hydroxyalkanoates) copolymers,
dialkanoyl polymers, polyvinyl acetates, polyethylene/vinyl alcohol
copolymers, lactic acid polymers, lactide polymers, glycolide
polymers, and mixtures thereof.
14. The thermoplastic composite of claim 10 wherein the filler is
selected from the group consisting of inorganic fillers, organic
fillers, and mixtures thereof.
15. The thermoplastic composite of claim 14 wherein the inorganic
filler is selected from the group consisting of clays, silica,
mica, wollastonite, calcium hydroxide, calcium carbonate, sodium
carbonate, magnesium carbonate, barium sulfate, magnesium sulfate,
kaolin, calcium oxide, magnesium oxide, aluminum hydroxide, talc,
titanium dioxide, and mixtures thereof.
16. The thermoplastic composite of claim 14 wherein the organic
filler is selected from the group consisting of wood flour, walnut
shell flour, alpha cellulose floc, cellulose fibers, chitin,
chitosan powders, organosilicone powders, nylon powders, polyester
powders, polypropylene powders, starch granules, and mixtures
thereof.
17. The thermoplastic composite of claim 10 wherein the composite
further comprises a lubricant selected from the group consisting of
metal soaps, hydrocarbon waxes, fatty acids, long-chain alcohols,
fatty acid esters, fatty acid amides, silicones, fluorochemicals,
acrylics, and mixtures thereof.
18. The thermoplastic composite of claim 10 wherein the composite
further comprises a plasticizer selected from the group consisting
of glycerin, triacetin, glycerol, monostearate, sorbitol,
erythritol, glucidol, mannitol, sucrose, ethylene glycol, propylene
glycol, diethylene glycol, triethylene glycol, diethylene glycol
dibenzoate, dipropylene glycol dibenzoate, triethylene glycol
caprate-caprylate, butylene glycol, pentamethylene glycol,
hexamethylene glycol, diisobutyl adipate, oleic amide, erucic
amide, palmitic amide, dimethyl acetamide, dimethyl sulfoxide,
methyl pyrrolidone, tetramethylene sulfone, oxa monoacids, oxa
diacids, polyoxa diacids, diglycolic acids, triethyl citrate,
acetyl triethyl citrate, tri-n-butyl citrate, acetyl tri-n-butyl
citrate, acetyl tri-n-hexyl citrate, alkyl lactates, phthalate
polyesters, adipate polyesters, glutate polyesters, diisononyl
phthalate, diisodecyl phthalate, dihexyl phthalate, alkyl alylether
diester adipate, dibutoxyethoxyethyl adipate, and mixtures
thereof.
19. A method of making a flushable tampon applicator wherein the
method comprises the steps of: (a) preparing a thermoplastic
composite comprising: (i) from 0% to about 90% by weight of a
water-dispersible polymer; (ii) from about 10% to about 50% by
weight of a biodegradable polymer; and (iii) from 0% to about 50%
by weight of a filler; and (b) injection molding the thermoplastic
composite into molded thermoplastic components used to construct
the flushable tampon applicator.
20. The method of claim 19 wherein the filler is selected from the
group consisting of inorganic fillers, organic fillers, and
mixtures thereof.
Description
[0001] This is a continuation-in-part application of application
Ser. No. 09/810,292, filed on Mar. 16, 2001, which is currently
pending.
FIELD OF THE INVENTION
[0002] The present invention relates to plastic tampon applicators
which are readily disposed in a sewage system and/or by
biodegradation. In particular, the present invention relates to
flushable tampon applicators which are made from thermoplastic
materials that are suitable for disposal in a toilet system.
BACKGROUND OF THE INVENTION
[0003] Feminine hygiene products such as tampons are commonly used
by female consumers. Tampons can be described as a feminine hygiene
article that has an absorbent device (i.e., pledget) withheld in a
paper or plastic applicator.
[0004] Paper and plastic tampon applicators typically comprise an
outer tubular member and a plunger for insertion of the pledget,
whereby these components of the paper and plastic applicators are
generally made from paper, paper coated, and plastic materials
which retain their form during use and are shelf-stable under
ambient conditions.
[0005] In addition to absorbent pledget devices, paper tampon
applicator components are suitable for disposal via a sewage system
or by biodegradable waste disposal means. Therefore, paper tampon
applicators are considered environmentally friendly in that these
paper tampon applicators can readily disintegrate in a sewage
system and/or can be disposed of through aerobic, anaerobic, and
natural degradation processes. However, paper tampon articles are
not very popular among females due to some tampon's pledget
insertion difficulties associated with the use of a paper tampon
applicator.
[0006] Certain female consumers prefer plastic tampon applicators
because the plastic applicators are made with a grip ring and
petal-shaped forward end which facilitate ease of insertion of a
tampon's pledget, although plastic tampon applicator components are
not easily disposed of as compared to paper applicator components.
Most plastic tampon applicators are made from polyethylene-based
polymeric materials that are not biodegradable and that do not
readily soften or break-up into smaller fragments for decomposition
in a sewage system, resulting in increased environmental concerns
for the disposal of plastic tampon applicators.
[0007] Many efforts to address the environmental concerns of the
disposal of plastic tampon applicators include the manufacture of
tampon applicators from thermoplastic materials other than
polyethylene polymers. Such attempts include tampon applicators
made from water-soluble materials, water-dispersible materials,
biodegradable materials, photodegradable materials, ultraviolet
light degradable materials, or combinations thereof. In particular,
one attempt to address the disposal of plastic tampon applicators
involves the use of plastic applicators made from biodegradable
polymers such as polyvinyl alcohol polymers. It is known that
tampon applicators made primarily from polyvinyl alcohol are
water-dispersible and biodegradable, however, such applicators have
been shown to suffer from issues involving moisture sensitivity,
stability, odor, and stickiness.
[0008] Other attempts in addressing the disposal of plastic tampon
applicators include plastic tampon applicators made from other
water-soluble materials such as polyethylene oxide polymers,
thermoplastic starch, and hydroxypropyl cellulose; plastic tampon
applicators made from combinations of water-soluble and
water-insoluble/biodegradable materials such as combinations of
polyvinyl alcohol and polycaprolactone, combinations of
polyethylene oxide and polycaprolactone, combinations of
polyethylene oxide and polyolefins such as polypropylene and
polyethylene; and combinations of polyvinyl alcohol and
polyethylene oxide polymers.
[0009] An example of a plastic tampon applicator constructed from a
combination of polyvinyl alcohol and polyethylene oxide is
disclosed in U.S. Pat. No. 5,395,308. This plastic tampon
applicator is described as being constructed to exhibit accelerated
break-up and rapid disintegration in liquid such as water so that
the plastic applicator can dissolve over an extended period of time
without causing problems in sewage systems such as a waste
treatment facility. The slow dissolution rate of these plastic
tampon applicators can lead to the clogging of toilet systems
and/or drain pipes because of the extended time required for these
plastic applicators to initially come in contact with liquid such
as toilet water and eventually reach waste disposal means at a
waste treatment facility, especially if multiple plastic
applicators are suited for disposal. Furthermore, plastic tampon
applicators comprising polyvinyl alcohol have been known to become
sticky when wet causing the applicator to stick to drain pipes
which can result in repeated flushings to dispose of the applicator
and to prevent clogging of toilet systems and/or the drain
pipes.
[0010] Therefore, the need exists for the manufacture of plastic
tampon applicators made from thermoplastic materials that are
flushable and can not only readily lose their structural integrity
as for example breaking apart in unrecognizable pieces in a sewage
system such as a toilet, but that can readily soften, disperse,
disintegrate, and/or dissolve in a toilet for clear passage through
the toilet to a municipal waste treatment facility. The tampon
applicator components should also be anerobically and/or
aerobically biodegradable, as well as provide for a flushable
tampon applicator that is not slimy, sticky, or tacky to the touch
before and during use.
[0011] To increase the flushability of plastic tampon applicators
and to improve the applicator aesthetics, ingredients such as
fillers, plasticizers, processing aids, dispersing agents,
lubricants, resin modifiers, clarifying/nucleating agents,
viscosity modifiers, and so forth are often included in the
manufacturing of the applicator. These ingredients help in the
process of the plastic tampon applicator as well as provide
improved structural characteristics to the final applicator product
form. For example, plasticizers can increase flow and
thermoplasticity of plastic materials by decreasing parameters such
as the viscosity of polymer melts, the glass transition
temperature, and the elasticity modulus of finished products to
result in flushable plastic tampon applicators that have improved
softness and flexibility. Lubricants are typically included as mold
release agents and slip/anti-blocking agents to increase the
overall rate of processing and to improve surface properties.
Lubricants have been shown to improve product properties such as
brightness, heat stability during processing, light stability,
better additive dispersion, and improved optical and mechanical
properties. Clarifying/nucleating agents are generally used to
increase the crystallization rate, reduce the size of crystals, and
improve transparency. Nucleating agents can also improve the
meltflow and demolding behavior of partly crystalline plastic
materials such as thermoplastic polyesters.
[0012] It has been found, however, that fillers such as calcium
carbonate and talc, are especially effective in providing for
plastic applicators that are nonsticky when wet, shelf stable, have
a smooth, soft texture and improved flushability. Filler materials
are also important ingredients for use in the processing of the
plastic applicators because they can assist in preventing the
thermoplastics from sticking to the surface of processing
equipment, reducing processing cycle time, acting as additional
mold release and slip/anti-blocking agents, and increasing
productivity. Another advantage of constructing flushable plastic
tampon applicators with filler ingredients is the reduced cost to
manufacture these applicators, especially when an acceptable
flushable, plastic applicator can be constructed with low cost
fillers to reduce the use of more costly thermoplastic
material.
[0013] Thus, not only does the need exist for plastic tampon
applicators that are readily flushable, but there's also a need to
provide flushable, plastic tampon applicators that meet consumer
acceptability for their structural integrity and aesthetic
characteristics of smoothness, flexibility, reduced stickiness,
stability, and the like.
SUMMARY OF THE INVENTION
[0014] The present invention is directed to flushable tampon
applicators which comprise (a) from 0% to about 90% by weight of a
water-dispersible polymer; (b) from about 10% to about 50% by
weight of a biodegradable polymer, and (c) from 0% to about 50% by
weight of a filler.
[0015] The present invention is also directed to a method of making
flushable tampon applicators wherein the method comprises (a)
preparing a thermoplastic composite comprising (i) from 0% to about
90% by weight of a water-dispersible polymer; (ii) from about 10%
to about 50% by weight of a biodegradable polymer; and (iii) from
0% to about 50% by weight of a filler; and (b) injection molding
the thermoplastic composite into molded thermoplastic components
used to construct the flushable tampon applicator.
[0016] It has been found that flushable tampon applicators can be
made from a combination of thermoplastic materials, especially a
blend of water-dispersible polymers such as high molecular weight
polyethylene oxides and low molecular weight polyethylene glycols,
and biodegradable polymers such as aliphatic/aromatic copolyesters,
to result in flushable tampon applicators that readily disintegrate
in a septic tank such as a toilet and are easily disposed of with
minimal or no environmental issues. The flushable tampon
applicators of the present invention comprise a combination of
water-dispersible and biodegradable thermoplastic polymers which
provide for improved disposal properties of the applicators. These
applicators are capable of being flushed down a toilet or any other
sewage system without causing drainage problems such as clogging,
and are capable of biodegradation disposal using commonly employed
biodegradation means.
[0017] It has also been found that flushable tampon applicators
have improved flushability and aesthetics when filler components
are included in the construction of the applicators. The flushable
tampon applicators are preferably constructed such that the filler
is melt blended with the thermoplastic materials to form a
composite mixture of filler particles and thermoplastic material,
wherein the filler particles are uniformly dispersed throughout the
applicator. The filler aids in the processing of the thermoplastic
materials into final flushable plastic tampon applicator product
forms that have improved flushability in addition to being
nonsticky when wet, shelf stable, smooth, and soft to the
touch.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] While the specification concludes with claims particularly
pointing out and distinctly claiming the subject matter of the
present invention, it is believed that the invention can be more
readily understood from the following description taken in
connection with the accompanying drawings, in which:
[0019] FIG. 1 is a perspective representation of a flushable tampon
applicator (10) of the present invention made from a blend of
thermoplastic materials. The flushable tampon applicator is
comprised of a thermoplastic outer tubular member (11) and a
thermoplastic inner tubular member or plunger (12). The outer
tubular member (11) can be any known or otherwise effective
thermoplastic, one-piece, hollow cylindrical body that has a
plurality of flexible petal tips (13) extending from and disposed
on the front end of the outer tube. The outer tubular member (11)
functions to contain or house an absorbent device such as a pledget
(not shown), and typically has a finger grip ring (14) formed on
the opposite end of the outer tube wherein the finger grip ring has
one or more ribs or protusions (15) on its exterior to provide a
gripping surface to assist a user in holding the flushable tampon
applicator (10). The finger grip portion of the outer tubular
member (11) can be of other configurations such as gripping rings
having score lines, ridges, dimples, one or more flat surfaces, a
roughed surface, and so forth.
[0020] The inner tubular member or plunger as referred to
hereinafter (12) includes any known or otherwise effective
thermoplastic plunger designed to be slidable and telescopically
mounted within the finger grip ring (14) such that the plunger (12)
can urge the pledget through the flexible petal tips (13) for
insertion of the pledget into a woman's vagina.
[0021] FIG. 2 is a cross-sectional view of a flushable tampon
applicator of the present invention depicting a pledget absorbent
device (16) positioned in the thermoplastic, cylindricallly shaped
outer tubular member (11). A withdrawal string (17) is permanently
attached to one end of the pledget (16) and provides a means of
withdrawing the soiled tampon pledget (16) from a woman's
vagina.
[0022] FIG. 3 is a perspective view of a flushable tampon
applicator (20) of the present invention having an outer tubular
member (18) and a plunger (19), both of which are constructed from
a composite of thermoplastic materials. The composite structure
includes one or more units of water-dispersible thermoplastic
polymers (21) affixed to one or more units of biodegradable
polymers (22) such that the units are arranged in an alternating
striped configuration. The composite structure can also be
constructed such that the alternating units of water-dispersible
and biodegradable polymers are arranged in a concentric ring
configuration or a layered structure of composite materials.
[0023] It should be noted that although the outer tubular members
(11) and (18) are shown as having cylindrical shapes, the outer
tubular members(II) and (18) can also be of square, elliptical,
conical, or oval configurations. Likewise, the plungers (12) and
(19), which are typically of an oval configuration, can be
configured in other shapes such as square, hemispherical, conical,
and elliptical. The outer tubular members and plungers described
herein can be constructed from clear, translucent, transparent,
colored, or opaque thermoplastic materials, or combinations
thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The flushable tampon applicators of the present invention
comprise an outer tubular member and plunger made from
water-dispersible and biodegradable materials that provide for
tampon applicators that are readily disposed by flushing the
applicator down a toilet, by biodegradable means, and/or by waste
disposal means at a municipal waste treatment facility.
[0025] The term "flushable" as used herein refers to materials
which are capable of softening, dissolving, dispersing,
disintegrating, and/or decomposing in a septic tank such as a
toilet to provide clearance when flushed down the toilet without
clogging the toilet or any other sewage drainage pipe.
[0026] The term "water-dispersible" as used herein refers to
materials that readily break apart in unrecognizable pieces upon
contact with water as a result of dissolution, solubilization,
dissipation, agitation, softening, or any other chemical or
mechanical dispersion means.
[0027] The term "biodegradable" as used herein refers to materials
that when disposed of after use will physically and biologically
decompose using known degradation procedures including aerobic,
anaerobic, and microbial digestion processes. The biodegradable
materials described herein include those degradable water-insoluble
materials that will also physically and biologically decompose
after disposal in a sewage system.
[0028] The term "ambient conditions" as used herein refers to
surrounding conditions at about one atmosphere of pressure, at
about 50% relative humidity, at about 25.degree. C.
[0029] The water-dispersible and biodegradable thermoplastic
polymers described herein can be generally defined according to
their weight or number average molecular weight. The weight average
molecular weight IMP) of a polymer is the summation of the weight
fraction of each molecular species present multiplied by its
molecular weight. The number average molecular weight (Mn) of a
polymer is the summation of the mole fraction of each molecular
species present multiplied by its molecular weight. The molecular
weight of polymer materials can typically be determined by Size
Exclusion Chromatography (SEC) or Gel Permeation Chromatography
(GPC) techniques well known in the art.
[0030] The thermoplastic polymers described herein are used to
construct the outer tubular member and plunger components of the
flushable tampon applicators of the present invention. These outer
tubular member and plunger components each have a density of
greater than about 1.0 grams per cubic centimeter (g/cm.sup.3) to
about 3.0 g/cm.sup.3. Thermoplastic components having a density of
greater than about 1.0 g/cm.sup.3 will easily fall to the bottom of
a septic tank such as a toilet, resulting in disposal of the
thermoplastic components without the need of repeated flushings.
The density of a given thermoplastic material and/or components
made from the material, will be dependent upon the degree of
interaction of attractive forces between the polymer chains in the
material, the degree of crystallinity of the thermoplastic
material, and the presence of any additives, fillers or other
optional components described herein. Therefore, if an individual
thermoplastic material does not have a density of greater than
about 1.0 g/cm.sup.3, the thermoplastic material can be combined
with other thermoplastic materials and/or optional ingredients
described herein to make suitable outer tubular members and
plungers having a density of greater than about 1.0 g/cm.sup.3.
Density values of the outer tubular and plunger components herein
can be determined by any known or otherwise effective method for
determining the density of thermoplastic materials and final
products made from these materials.
[0031] The flushable tampon applicators of the present invention
can comprise, consist of, or consist essentially of the elements
and limitations of the invention described herein, as well as any
of the additional or optional ingredients, components, or
limitations described herein.
[0032] All percentages, parts and ratios are by weight of the total
applicator device, unless otherwise specified. All such weights as
they pertain to listed ingredients are based on the specific
ingredient level and, therefore, do not include carriers or
by-products that may be included in commercially available
materials, unless otherwise specified.
Applicator Components
[0033] The flushable tampon applicators of the present invention
typically comprise an outer tubular member and a plunger made from
any known or otherwise effective thermoplastic materials that can
readily soften and disintegrate upon contact with water such as
toilet water. The thermoplastic materials are preferably
combinations of water-dispersible and biodegradable polymers that
are structurally stable before and during use while also being
capable of rapid softening and disintegration in a toilet sewage
system to provide disposal via the toilet to her enhance any
additional disposal such as further disposal treatment of
biodegradation and/or municipal waste disposal.
[0034] The outer tubular member and plunger components of the
flushable tampon applicator of the present invention can be
constructed from the same or otherwise different water-dispersible
and biodegradable materials. In other words, the outer tubular
member and plunger both can be made from an individual or
combination of water-dispersible materials; the outer tubular
member and plunger both can be made from an individual or
combination of biodegradable materials; the outer tubular member
and plunger both can be made from a combination of
water-dispersible and biodegradable materials; the outer tubular
member can be made from water-dispersible materials and the plunger
can be made from biodegradable materials; or the outer tubular
member can be made from biodegradable materials and the plunger can
be made from water-dispersible materials.
[0035] Construction of the outer tubular member and plunger
components from the same or otherwise different combination of
materials provide, for example, a flushable tampon applicator that
has an outer tubular member with a lower stiffness or hardness
relative to the plunger to increase insertion comfort. The outer
tubular member and plunger may also be constructed from different
combinations of materials to incorporate, for example, a
flushability signal, such as a color change or effervescence, to
the user. The water-dispersible and biodegradable materials from
which the outer tubular member and plunger can be made are
described in detail hereinbelow.
[0036] Water-Dispersible Components
[0037] The flushable tampon applicators of the present invention
comprise a total of from 0% to about 99%, preferably from about 5%
to about 90%, more preferably from about 10% to about 80% of
water-dispersible thermoplastic polymers by weight of the
applicator. The water-dispersible thermoplastic polymers can be
used individually or as a combination of polymers provided that the
water-dispersible thermoplastic polymers can readily disintegrate
in water, and can be combined with one or more biodegradable
polymers described hereinafter.
[0038] The water-dispersible thermoplastic polymers suitable for
use herein include those water-dispersible compounds that can
readily disintegrate in water such as toilet water while being
structurally stable before contact with the water. The terms
"structurally stable" and "structural stability" are used
interchangeably herein to refer to materials that maintain their
molded shape, form, and chemical composition before and during use,
and that do not become sticky or slimy to the touch upon contact
with moisture-laden air and/or moist human tissue.
[0039] Nonlimiting examples of suitable water-dispersible
thermoplastic polymers include high molecular weight polyethylene
oxides, low molecular weight polyethylene glycols,
polyethylene/polypropylene oxide copolymers,
polyethylene/polybutylene oxide copolymers,
polyethylene/polypropylene glycol copolymers, thermoplastic starch
polymers, polyvinyl alcohols, partially hydrolyzed polyvinyl
alcohols, modified polyvinyl alcohols, infrared treated polyvinyl
alcohols, cross-linked polyvinyl alcohols such as a polyvinyl
alcohol cross-linked with an aldehyde, alkali metal sulfonate
thermoplastic polyesters, hydroxyethyl celluloses, hydroxypropyl
celluloses, methylated hydroxypropyl celluloses, polyacrylic acids,
polyaspartic acids, polymethacrylic acids, polysaccharides
excluding sucrose polysaccharides suitable for use as a
plasticizing agent herein, proteins, polyvinyl pyrrolidone
homopolymers, polyvinyl pyrrolidone copolymers including polyvinyl
pyrrolidonelvinyl acetate copolymers and polyvinyl
pyrrolidone/acrylic acid copolymers, polyvinyl methyl ether
homopolymers, polyoxazolines including polyethyloxazoline and
poly(2-isopropyl-2-oxazoline), polyvinyl methyl oxazolidones,
polyvinyl methyl oxazolidimones, polyethyleminines,
polyacrylamides, polyvinyl methyl ether/maleic anhydride
copolymers, water-dispersible polyurethanes, water-dispersible
sulfonate polyesters, and mixtures thereof. Preferred
water-dispersible thermoplastic polymers include high molecular
weight polyethylene oxides and low molecular weight polyethylene
glycols.
[0040] Preferred high molecular weight polyethylene oxides and low
molecular weight polyethylene glycols suitable for use as
water-dispersible thermoplastic polymers herein include those
polyethylene oxides and polyethylene glycols which conform to the
formula: 1
[0041] and those polyethylene glycols which conform to the formula:
2
[0042] wherein n has an average value of from about 500 to about
180,000, preferably from about 650 to about 50,000, more preferably
from about 800 to about 25,000, for high molecular weight
polyethylene oxides; and an average value of from about 12 to about
465, preferably from about 12 to about 341, more preferably from
about 13 to about 227, for low molecular weight polyethylene
glycols. These materials are polymers of ethylene oxide, which are
also known as polyethylene oxides, polyoxyethylenes, polyethylene
glycols, and polymethoxyethylene glycols.
[0043] Specific examples of preferred high molecular weight
polyethylene oxides suitable for use as a water-dispersible
thermoplastic polymer herein include, but are not limited to,
polyethylene oxides having repeating alkylene oxide radicals in the
ranges described hereinabove, and a weight average molecular weight
of from about 65,000 daltons to about 8,000,000 daltons, preferably
from about 80,000 daltons to about 2,000,000 daltons, more
preferably from about 100,000 daltons to about 900,000 daltons.
These polyethylene oxide polymers are prepared by methods known in
the art for making high molecular weight copolymers and
interpolymers of ethylene oxide. For example, the high molecular
weight copolymers of polyethylene oxide are prepared using ionic
catalysts to react ethylene oxide with oxirane compounds such as
styrene oxide, propylene oxide, butylene oxide, and the like. High
molecular weight interpolymers of polyethylene oxide are prepared
by co-polymerizing polyethylene oxide with one or more vinyl
monomers such as N,N-dimethylaminoethyl methacrylate, styrene,
methyl methacrylate, 2-methyl-5-vinyl pyridine, acrylonitrile,
hydroxyethyl methacrylate, acrylic acid, acrylamide, and the like.
Grafted or chemically modified high molecular weight polyethylene
oxides are also suitable for use as a water-dispersible
thermoplastic polymer herein.
[0044] The weight average molecular weight (M.sub.w) of the high
molecular weight polyethylene oxides can be determined by measuring
the intrinsic viscosity of a polyethylene oxide material in water
at 30.degree. C. The intrinsic viscosity, [.eta.], is correlated to
the M.sub.w of polyethylene oxide materials, and can be expressed
by the following equation:
[.eta.]=1.25.times.10.sup.-4M.sub.w.sup.0.78.
[0045] Examples of commercially available high molecular weight
polyethylene oxide polymers are the polyethylene oxides which are
sold under the tradename POLYOX.RTM., and which are available from
the Dow Chemical Company located in Midland, Mich.. Specific
examples of such polyethylene oxides include POLYOX.RTM. WSR-10
which has a M.sub.w of about 100,000; POLYOX.RTM. WSR-80 which has
a M.sub.w of about 200,000; POLYOX.RTM. WSR-N-750 which has a
M.sub.w of about 300,000; POLYOX.RTM. WSR-N-3000 which has a
M.sub.w of about 400,000; POLYOX.RTM. WSR-3333 which has a M.sub.w
of about 400,000; POLYOX.RTM. WSR-205 which has a M.sub.w of about
600,000; POLYOX.RTM. WSR-1105 which has a M.sub.w of about 900,000;
POLYOX.RTM. WSR-N-K12 which has a M.sub.w of about 1,000,000;
POLYOX.RTM. WSR-N-K60 which has a M.sub.w of about 2,000,000;
POLYOX.RTM. WSR-301 which has a M.sub.w of about 4,000,000;
POLYOX.RTM. WSR Coagulant which has a M.sub.w of about 5,000,000;
POLYOX.RTM. WSR-303 which has a M.sub.w of about 7,000,000;
POLYOX.RTM. WSR-308 which has a M.sub.w of about 8,000,000; and
mixtures thereof.
[0046] Specific examples of preferred low molecular weight
polyethylene glycols suitable for use as a water-dispersible
thermoplastic polymer herein include, but are not limited to,
polyethylene glycols having repeating alkylene oxide radicals in
the ranges described hereinabove, and a number average molecular
weight of from about 500 daltons to about 20,000 daltons,
preferably from about 550 daltons to about 15,000 daltons, more
preferably from about 600 daltons to about 10,000 daltons. The
number average molecular weight (M.sub.n) of the low molecular
weight polyethylene glycols can be determined by known titration
procedures used to determine the number of molecules having
hydroxy-end groups wherein the M.sub.n is calculated based on the
weight of a given polyethylene glycol divided by the number of
hydroxy-end group-containing molecules within the polyethylene
glycol polymer.
[0047] Nonlimiting examples of the preferred low molecular weight
polyethylene glycols include those polyethylene glycols (PEG) and
polymethoxyethylene glycols (MPEG) that are commercially available
from Dow Chemical, and sold as PEG-600 which has a M.sub.n of about
600; PEG-900 which has a M.sub.n of about 900; PEG-1000 which has a
M.sub.n of about 1000; PEG-1450 which has a M.sub.n of about 1450;
PEG-3350 which has a M.sub.n of about 3350; PEG-4000 which has a
M.sub.n of about 4,000; PEG-4600 which has a M.sub.w of about 4600;
PEG-8000 which has a M.sub.w of about 8,000; MPEG-550 which has a
M.sub.n of about 550; MPEG-750 which has a M.sub.n of about 750;
MPEG-2000 which has a M.sub.n of about 2,000; MPEG-5000 which has a
M.sub.n of about 5,000; and mixtures thereof.
[0048] Specific examples of polyvinyl alcohols suitable for use as
a water-dispersible thermoplastic polymer herein include, but are
not limited to, those water-soluble thermoplastic polymers prepared
by the partial or complete hydrolysis of polyvinyl acetate. The
degree of hydrolysis of polyvinyl acetate results in polyvinyl
alcohols having different residual acetyl groups and therefore
different molecular weight and viscosity characteristics.
Accordingly, the water solubility of the polyvinyl alcohol can be
regulated by controlling the hydrolysis, molecular weight, and
viscosity of the specific polyvinyl alcohol resin. Nonlimiting
examples of such suitable polyvinyl alcohols include polyvinyl
alcohols having a percent hydrolysis of from about 74% to about
98%, specific nonlimiting examples of which include polyvinyl
alcohol 98% hydrolyzed ultra low viscosity resin having a viscosity
of from about 3.2 centipoises (cps) to about 4.2 cps, and a weight
average molecular weight of from about 13,000 daltons to about
23,000 daltons; polyvinyl alcohol 88% hydrolyzed ultra low
viscosity resin having a viscosity of from about 3.0 cps to about
4.0 cps, and a weight average molecular weight of from about 13,000
daltons to about 23,000 daltons; polyvinyl alcohol 88% hydrolyzed
low viscosity resin having a viscosity of from about 5.2 cps to
about 6.2 cps, and a weight average molecular weight of from about
31,000 daltons to about 50,000 daltons; and mixtures thereof.
[0049] The viscosity of the polvinyl alcohols and any other
suitable thermoplastic polymer and optional ingredient described
herein are measured or determined under ambient conditions, unless
otherwise specified, using suitable methods known in the art.
Examples of methods for measuring or determining viscosity include
method DIN 53 015 which involves the use of a Hoppler falling-ball
viscometer for measuring dynamic viscosity in units of
Pascal-seconds (Pa-s), and methods DIN 53 562 and DIN 53 012 which
involve the use of a Ubbelohde glass capillary viscometer to
measure kinematic viscosity in units of square centimeters per
second (cm.sup.2/sec).
[0050] Other examples of suitable polyvinyl alcohols include, but
are not limited to, water dispersible polyvinyl alcohol resins that
have been modified to contain pendant alcohol groups. These
modified polyvinyl alcohols can be produced by polymerizing a
polyethylene oxide acrylate with vinyl acetate and then hydrolyzing
the resultant polymer to produce pendant alcohol groups. Modified
polyvinyl alcohols prepared by this procedure typically have
viscosities ranging from about 500 poise to about 4,500 poise
dependent upon the shear rate used to form the modified polyvinyl
alcohol into a molded thermoplastic polymer. Examples of
commercially available modified polyvinyl alcohols include those
modified polyvinyl alcohol resins manufactured by Texas Polymer
Services Incorporation (Houston, Tex.), and sold under the VINEX
and AIRVOL tradenames. Specific examples of commercially available
VINEX resins include, but are not limited to, VINEX 2019, VINEX
2025, VINEX 2034, and VINEX 2144. Specific examples of AIRVOL
resins include, but are not limited to, AIRVOL 125 and AIRVOL
325.
[0051] Other examples of suitable polyvinyl alcohols include, but
are not limited to, the polyvinyl alcohols that are commercially
available from Clariant GmbH (Sulzbach, Germany) under the MOWIOL
tradename. Specific examples of MOWIOL resins include MOWIOL 18-88,
MOWIOL 26-88, and MOWIOL 30-92.
[0052] Nonlimiting specific examples of alkali metal sulfonate
polyesters suitable for use as a water-dispersible thermoplastic
polymer herein include those water-dispersible, linear
thermoplastic polyesters which contain carbonyloxy-linking groups
in the linear, molecular structure. The alkali metal sulfonate
polyesters are typically prepared by reacting at least one
difunctional dicarboxylic acid, at least one diol, and at least one
difunctional sulfomonomer containing at least one metal sulfonate
group attached to an aromatic nucleus having the functional group
carboxyl. The number average molecular weight of suitable alkali
metal sulfonate polyesters ranges from about 13,000 daltons to
about 19,000 daltons, based on the number of repeating sulfomonomer
groups in the molecule. It is believed that the sulfomonomer
substituent is primarily responsible for the water dispersibility
of the thermoplastic polyester. Nonlimiting examples of
commercially available water-dispersible, linear thermoplastic
polyesters include the alkali metal sulfonates sold under the
tradename Eastman AQ.RTM. polymer from Eastman Chemical Products,
Incorporation located in Kingsport, Tenn., specific examples of
which include Eastman AQ(D 1045, Eastman AQ.RTM. 1350, Eastman AQS
1950, Eastman AQ.RTM. 14,000, Eastman AQ.RTM. 29S, Eastman LB-100
AQ.RTM. 29S, Eastman AQ.RTM. 55S, Eastman AQ.RTM. 38S, Eastman
AQ.RTM. 48, and mixtures thereof.
[0053] Biodegradable Components
[0054] The flushable tampon applicators of the present invention
comprise a total of from about 1% to about 99%, preferably from
about 5% to about 95%, more preferably from about 10% to about 90%
of biodegradable thermoplastic polymers by weight of the
applicator. The biodegradable thermoplastic polymers can be used
individually or as a combination of polymers provided that the
biodegradable thermoplastic polymers are degradable by biological
and environmental means, and that they are compatible for
combination with one or more water-dispersible polymers described
hereinabove, The biodegradable polymers suitable for use herein are
those biodegradable materials which are susceptible to being
assimilated by microorganisms such as molds, fungi, and bacteria
when the biodegradable material is buried in the ground or
otherwise comes in contact with the microorganisms including
contact under environmental conditions conducive to the growth of
the microorganisms.
[0055] Suitable biodegradable polymers also include those
biodegradable materials which are environmentally degradable using
aerobic or anerobic digestion procedures, or by virtue of being
exposed to environmental elements such as sunlight, rain, moisture,
wind, temperature, and the like.
[0056] Nonlimiting examples of biodegradable thermoplastic polymers
suitable for use in the flushable tampon applicators of the present
invention include aliphatic polyesteramides; diacid/diol-based
aliphatic polyesters; aromatic polyesters including modified
polyethylene terephthalates; aliphatic/aromatic copolyesters;
polycaprolactones; polycaprolactone copolymers;
poly(3-hydroxyalkanoates) including poly(3-hydroxybutyrates),
poly(3-hydroxyhexanoates), and poly(3-hydroxyvalerates);
poly(3-hydroxyalkanoates) copolymers including poly(3-hydroxy)
butyrate/valerate copolymers; polyesters and polyurethanes derived
from aliphatic polyols (i.e., dialkanoyl polymers); polyvinyl
acetates; polyethylene/vinyl alcohol copolymers; lactic acid
polymers including lactic acid homopolymers and lactic acid
copolymers; lactide polymers including lactide homopolymers and
lactide copolymers; glycolide polymers including glycolide
homopolymers and glycolide copolymers; and mixtures thereof.
Preferred are aliphatic polyesteramides, diacid/diol-based
aliphatic polyesters, poly(3-hydroxyalkanoates),
poly(3-hydroxyalkanoates) copolymers, aliphatic/aromatic
copolyesters, lactic acid polymers, and lactide polymers.
[0057] Specific examples of preferred aliphatic polyesteramides
suitable for use as a biodegradable thermoplastic polymer herein
include, but are not limited to, aliphatic polyesteramides which
are reaction products of a synthesis reaction of diols,
dicarboxylic acids, and aminocarboxylic acids; aliphatic
polyesteramides formed from reacting lactic acid with diamines and
dicarboxylic acid dichlorides; aliphatic polyesteramides formed
from caprolactone and caprolactam; aliphatic polyesteramides formed
by reacting acid-terminated aliphatic ester prepolymers with
aromatic diisocyanates; aliphatic polyesteramides formed by
reacting aliphatic esters with aliphatic amides; and mixtures
thereof. Aliphatic polyesteramides formed by reacting aliphatic
esters with aliphatic amides are most preferred.
[0058] Preferred aliphatic polyesteramides which are copolymers of
aliphatic esters and aliphatic amides can be characterized in that
these copolymers generally contain from about 30% to about 70%,
preferably from about 40% to about 80% by weight of aliphatic
esters, and from about 70% to about 30%, preferably from about 60%
to about 20% by weight of aliphatic amides. The weight average
molecular weight of these copolymers ranges from about 10,000
daltons to about 500,000 daltons, preferably from about 20,000
daltons to about 300,000 daltons as measured by known gel
chromatography techniques used in the determination of molecular
weight of polymers.
[0059] The aliphatic ester and aliphatic amide copolymers of the
preferred aliphatic polyesteramides are derived from monomers such
as dialcohols including ethylene glycol, diethylene glycol,
1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, and the like;
dicarboxylic acids and dicarboxylhc acid esters including oxalic
acid, succinic acid, adipic acid, oxalic acid esters, succinic acid
esters, adipic acid esters, and the like; hydroxycarboxylic acid
and lactones including caprolactone, and the like; aminoalcohols
including ethanolamine, propanolamine, and the like; cyclic lactams
including s-caprolactar, lauric lactam, and the like;
(o-aminocarboxylic acids including aminocaproic acid, and the like;
1:1 salts of dicarboxylic acids and diamines including 1:1 salt
mixtures of dicarboxylic acids such as adipic acid, succinic acid,
and the like, and diamines such as hexamethylenediamine,
diaminobutane, and the like; and mixtures thereof.
Hydroxy-terminated or acid-terminated polyesters such as acid
terminated oligoesters can also be used as the ester-forming
compound. The hydroxy-terminated or acid terminated polyesters
typically have number average molecular weights of from about 200
daltons to about 10,000 daltons.
[0060] The preferred aliphatic polyesteramides can be prepared by
any suitable synthesis or stoichiometric technique known in the art
for forming aliphatic polyesteramides having aliphatic ester and
aliphatic amide monomers. A typical synthesis involves
stoichiometrically mixing the starting monomers, optionally adding
water to the reaction mixture, polymerizing the monomers at an
elevated temperature of about 220.degree. C., and subsequently
removing the water and excess monomers by distillation using vacuum
and elevated temperature, resulting in a final copolymer of an
aliphatic polyesteramide. Other suitable techniques involve
transesterification and transamidation reaction procedures. As
apparent by those skilled in the art, a catalyst can be used in the
above-described synthesis reaction and transesterification or
transaindation procedures, wherein suitable catalysts include
phosphorous compounds, acid catalysts, magnesium acetates, zinc
acetates, calcium acetates, lysine, lysine derivatives, and the
like.
[0061] The preferred aliphatic polyesteramides comprise copolymer
combinations of adipic acid, 1,4-butanediol, and 6-aminocaproic
acid with an ester portion of 45%; adipic acid, 1,4-butanediol, and
.epsilon.-caprolactam with an ester portion of 50%; adipic acid,
1,4-butanediol, and a 1:1 salt of adipic acid ("AH salt") and
1,6-hexamethylenediamine; and an acid-terminated oligoester made
from adipic acid, 1,4-butanediol, 1,6-hexamethylenediamine, and
s-caprolactam. These preferred aliphatic polyesteramides have
melting points of from about 115.degree. C. to about 155.degree. C.
and relative viscosities (1 wt. % in m-cresol at 25.degree. C.) of
from about 2.0 to about 3.0, and are commercially available from
Bayer Aktiengesellschaft located in Leverkusen, Germany under the
BAK.RTM. tradename. Specific examples of such commercially
available polyesteramides include BAK.RTM. 402, BAK.RTM. 403, and
BAK.RTM. 404.
[0062] Specific examples of preferred diacid/diol-based aliphatic
polyesters suitable for use as a biodegradable thermoplastic
polymer herein include, but are not limited to, aliphatic
polyesters produced either from ring opening reactions or from the
condensation polymerization of aliphatic diacids and aliphatic
diols, wherein the number average molecular weight of these
aliphatic polyesters typically range from about 30,000 daltons to
about 300,000 daltons. The preferred diacid/diol-based aliphatic
polyesters are reaction products of a C.sub.2-C.sub.10 diol reacted
with oxalic acid, succinic acid, adipic acid, suberic acid, sebacic
acid, copolymers thereof, or mixtures thereof. Nonlimting examples
of preferred diacid/diol-based aliphatic polyesters include
polyalkylene succinates such as polyethylene succinate, and
polybutylene succinate; polyalkylene succinate copolymers such as
polyethylene succinate/adipate copolymer, and polybutylene
succinate/adipate copolymer; polypentamethyl succinates;
polyhexamethyl succinates; polyheptamethyl succinates;
polyoctamethyl succinates; polyalkylene oxalates such as
polyethylene oxalate, and polybutylene oxalate; polyalkylene
oxalate copolymers such as polybutylene oxalate/succinate copolymer
and polybutylene oxalate/adipate copolymer; polybutylene
oxalate/succinate/adipate terpolymers; and mixtures thereof. An
example of suitable commercial diacid/diol-based aliphatic
polyesters is the polybutylene succinate/adipate copolymers sold
under the BIONOLLE 1000 and BIONOLLE 3000 tradenames from the Showa
Highpolymer Company, Ltd. located in Tokyo, Japan.
[0063] Specific examples of preferred poly(3-hydroxyalkanoates)
suitable for use as a biodegradable thermoplastic polymer herein
include, but are not limited to, the poly(3-hydroxyalkanoates
commercially available under the Biomer 209H and Biomer 240H
tradenames from the Biomer Company located in Krailling, Germany.
Specific examples of preferred poly(3-hydroxyalkanoates) copolymers
suitable for use as a biodegradable polymer herein include, but are
not limited to the poly(3-hydroxy) butyrate/valerate copolymers
disclosed in U.S. Pat. No. 5,391,423, issued to Wnuk et al. on Feb.
21 1995, which disclosure is incorporated by reference herein; and
the poly(3-hydroxy) butyrate/valerate copolymers such as
poly(3-hydroxybutyrate-co-3-hydroxyhexanoate),
poly(3-hydroxybutyrate-co-3-hydroxyoctanoate),
poly(3-hydroxybutyrate-co-- 3-hydroxynonanoate),
poly(3-hydroxybutyrate-co-3-hydroxydecanoate),
poly(3-hydroxybutyrate-co-3-hydroxydocosanoate),
poly(3-hydroxybutyrate-c- o-3-hydroxyhexadecanoate),
poly(3-hydroxyvalerate-co-3-hydroxyoctanoate),
poly(3-hydroxybutyrate-co-3-hydroxyvalerateco-3-hydroxyoctanoate),
poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxydecanoate),
and
poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyoctanoate-co-3-hy-
droxydecanoate) disclosed in U.S. Pat, No. 5,489,470, issued to
Noda on Feb. 6, 1996, which disclosure is incorporated by reference
herein.
[0064] Specific examples of preferred aliphatic/aromatic
copolyesters suitable for use as a biodegradable thermoplastic
polymer herein include, but are not limited to, those
aliphatic/aromatic copolyesters that are random copolymers formed
from a condensation reaction of dicarboxylic acids or derivatives
thereof and diols. Suitable dicarboxylic acids include, but are not
limited to, malonic, succinic, glutaric, adipic, pimelic, azelaic,
sebacic, fumaric, 2,2-dimethyl glutaric, suberic,
1,3-cyclopentanedicarboxylic, 1,4-cyclohexanedicarboxylic,
1,3-clohexanedicarboxylic, diglycolic, itaconic, maleic,
2,5-norbornanedicarboxylic, 1,4-terephthalic, 1,3-terephthalic,
2,6-naphthoic, 1,5-naphthoic, ester forming derivatives thereof,
and combinations thereof. Suitable diols include, but are not
limited to, ethylene glycol, diethylene glycol, triethylene glycol,
tetraethylene glycol, propylene glycol, 1,3-propanediol,
2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol,
thiodiethanol, 1,3-cyclohexanedimethanol,
1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol,
and combinations thereof. Nonlimiting examples of such
aliphatic/aromatic copolyesters include a 50/50 blend of
poly(tetramethylene glutarate-co-terephthalate), a 60/40 blend of
poly(tetramethylene glutarate-co-terephthalate), a 70/30 blend of
poly(tetramethylene glutarate-co-terephthalate), an 85/15 blend of
poly(tetramethylene glutarate-co-terephthalate), a 50/45/15 blend
of poly(tetramethylene glutarate-co-terephthalate-co-diglycolate),
a 70/30 blend of poly(ethylene glutarate-co-terephthalate), an
85/15 blend of poly(tetramethylene adipate-co-terephthalate), an
85/15 blend of poly(tetramethylene succinate-co-terephthalate), a
50/50 blend of poly(tetramethylene-co-ethylene
glutarate-co-terephthalate), and a 70/30 blend of
poly(tetramethylene-co-ethylene glutarate-co-terephthalate). These
aliphatic/aromatic copolyesters, in addition to other suitable
aliphatic/aromatic polyesters, are further described in U.S. Pat.
No. 5,292,783 issued to Buchanan et al. on Mar. 8, 1994, which
descriptions are incorporated by reference herein. The
poly(tetramethylene adipate-co-terephthalate) is a preferred
aliphatic/aromatic copolyester that is commercially available from
Eastman Chemical (Kingsport, Tenn.) under the Eastar Biodegradable
Copolyester 14776 tradename.
[0065] Specific examples of preferred lactic acid polymers and
lactide polymers suitable for use as a biodegradable thermoplastic
polymer herein include, but are not limited to, those polylactic
acid-based polymers and polylactide-based polymers that are
generally referred to in the industry as "PLA". Therefore, the
terms "polylactic acid", "polylactide" and "PLA" are used
interchangeably to include homopolymers and copolymers of lactic
acid and lactide based on polymer characterization of the polymers
being formed from a specific monomer or the polymers being
comprised of the smallest repeating monomer units. In other words,
polylactide is a dimeric ester of lactic acid and can be formed to
contain small repeating monomer units of lactic acid (actually
residues of lactic acid) or be manufactured by polymerization of a
lactide monomer, resulting in polylactide being referred to both as
a lactic acid residue containing polymer and as a lactide residue
containing polymer. It should be understood, however, that the
terms "polylactic acid", "polylactide", and "PLA" are not intended
to be limiting with respect to the manner in which the polymer is
formed.
[0066] The polylactic acid polymers generally have a lactic acid
residue repeating monomer unit that conforms to the following
formula: 3
[0067] The polylactide polymers generally having lactic acid
residue repeating monomer units as described herein-above, or
lactide residue repeating monomer units that conform to the
following formula: 4
[0068] Typically, polymerization of lactic acid and lactide will
result in polymers comprising at least about 50% by weight of
lactic acid residue repeating units, lactide residue repeating
units, or combinations thereof. These lactic acid and lactide
polymers include homopolymers and copolymers such as random and/or
block copolymers of lactic acid and/or lactide. The lactic acid
residue repeating monomer units can be obtained from L-lactic acid
and D-lactic acid. The lactide residue repeating monomer units can
be obtained from L-lactide, D-lactide, and meso-lactide.
[0069] Suitable lactic acid and lactide polymers include those
homopolymers and copolymers of lactic acid and/or lactide which
have a weight average molecular weight generally ranging from about
10,000 daltons to about 600,000 daltons. An example of commercially
available polylactic acid polymers includes a variety of polylactic
acids that are available from the Chronopol Incorporation located
in Golden, Colorado. An example of commercially available
polylactide polymers includes the polylactides sold under the
tradename EcoPLA.RTM.. An example of commercially available "PLA"
polymers includes PLA 44D and PLA 62-50, both of which are
available from Cargill-Dow Polymers, LLC located in Minnetonka,
Minn. Other suitable polylactic acid polymers and copolymers
include polylactic acid prepared by direct polycondensation of
lactic acid (available from the Mitsui Chemical Incorporation under
the tradename LACEA), and a block copolymer comprising a polylactic
acid hard segment and a polyoxyalkylene dialkanoate soft segment
(available from the Dainippon Ink and Chemicals Incorporation and
the Shimadzu Corporation, both of which are located in Japan).
[0070] Specific examples of other suitable biodegradable polymers
include polycaprolactone polyesters having a number average
molecular weight of from about 10,000 daltons to about 80,000
daltons. Commercially suitable polycaprolactone polymers are the
polycaprolactones available from the Union Carbide Corporation sold
under the TONE tradename, examples of which include Tone P-767,
Tone P-787, and Tone P-303. Tone P-767 has a number average
molecular weight of about 43,000 daltons. Tone P-787 has a number
average molecular weight of about 80,000 daltons. Tone P-303 is an
A-B-A block polymer of Tone P-767 polycaprolactone and polyethylene
oxide, and has a number average molecular weight of from about
30,000 daltons to about 35,000 daltons.
[0071] The biodegradable polymers described herein, in addition to
thermoplastic compositions containing these polymers, will
physically and biologically decompose using known degradation
procedures such as aerobic, anaerobic, and microbial digestion
processes. One such method of evaluating the decomposition of
biodegradable materials includes an anaerobic disintegration
procedure which involves measuring the percent weight loss of
thermoplastic compositions containing biodegradable polymers.
Typically, thermoplastic compositions containing biodegradable
polymers are exposed to anaerobic sludge that can be obtained from
a municipal wastewater treatment plant (e.g., sludge that has a pH
of or between about 7 and 8, and about 1% total solids). The
sludge-exposed thermoplastic compositions are allowed to
disintegrate or decompose for 7, 14, and 28 days at 35.degree. C.
under controlled incubator conditions. After the 7, 14, or 28 day
incubation period, the sludge-exposed thermoplastic compositions
are evaluated for percent weight loss by recovering any
undisintegrated portions of the compositions, drying these
undisintegrtaed portions at 40.degree. C. for at least 2 hours
after a tap water rinsing, and determining the weight of the dried
undisintegrated portions. The percent weight loss is calculated
based on the weight of the thermoplastic compositions before and
after exposure to sludge for a given time period. It has been found
that the biodegradable polymer containing-thermoplastic
compositions described herein lose their structural integrity by
breaking apart into smaller pieces and/or by shrinking into smaller
fragments after being exposed to sludge for only 7 days. Anaerobic
biodegradation of these biodegradable polymer
containing-thennoplastic compositions increased after the
compositions were exposed to sludge for periods of 14 and 28
days.
[0072] Filler Components
[0073] In addition to the water-dispersible and biodegradable
thermoplastic materials, the flushable tampon applicators of the
present invention preferably comprise one or more fillers which can
aid in the applicators having an opaque appearance and provide for
applicators that have a smooth, soft texture and improved
water-dispersibility. The filler can be added by compounding the
filler with the thermoplastic polymers and any optional ingredient
described herein, and processing this compounded mixture according
to the disclosed methods of constructing flushable tampon
applicators of the present invention. Preferably, the flushable
tampon applicators are constructed such that the filler is melt
blended with the thermoplastic polymers to form a composite of
thermoplastic material and discrete filler particles that are
uniformly dispersed throughout the composite, flushable tampon
applicator structure.
[0074] Suitable fillers include inorganic and organic filler
materials. Nonlimiting examples of suitable inorganic fillers
include clays, silica, mica, wollastonite, calcium hydroxide,
calcium carbonate, sodium carbonate, magnesium carbonate, barium
sulfate, magnesium sulfate, kaolin, calcium oxide, magnesium oxide,
aluminum hydroxide, magnesium silicates including talc, titanium
dioxide, and mixtures thereof. Nonlimiting examples of suitable
organic fillers include wood flour, walnut shell flour, alpha
cellulose floc, cellulose fibers, chitin, chitosan powders,
organosilicone powders, nylon powders, polyester powders,
polypropylene powders, starch granules, and mixtures thereof.
Filler components such as calcium carbonate, talc, barium sulfate,
starch granules, and wood flour are preferred.
[0075] The fillers are typically included at total filler
concentrations ranging from 0% to about 70%, preferably from about
5% to about 65%, more preferably from about 8% to about 60% by
weight of the applicator. The inclusion of filler components within
the defined concentration ranges have been found to provide the
flushable tampon applicators with improved disintegration rate for
spontaneous flushability in addition to the flushable tampon
applicators being shelf stable, nonsticky when wet, nontacky when
wet, and smooth to the touch. The filler components can be included
in the construction of the flushable tampon applicators as an
individual filler or a combination of filler components provided
that the total filler concentration is within these defined
concentration ranges.
[0076] Specific examples of calcium carbonates suitable for use of
a filler herein, include but are not limited to, the calcium
carbonates commercially available from Specialty Minerals
(Bethlehem, Pa.) under the Vicron 15-15, Vicron 10-25, and Vicron
25-11 tradenames.
[0077] Specific examples of magnesium silicates such as talc which
are suitable for use as a filler herein include, but are not
limited to, ABT 2500 talc and OPTIBLOC 10 talc, both of which are
available from Specialty Minerals.
[0078] Specific examples of starch granule materials suitable for
use as a filler herein include, but are not limited to, the corn
starch materials sold under the Staley STAR-DRI.RTM. 1 and Staley
Pure Food Powdered tradenames, both of which are commercially
available the A. E. Staley Manufacturing Company (Decatur, Ill.);
Clinton 290 which is commercially available from ADM Corn
Processing (Decatur, Ill.); and National Starch Melojel which is
commercially available from National Starch & Chemical
(Bridgewater, N.J.).
[0079] Specific examples of wood flour materials suitable for use
as a filler herein include, but are not limited to, Maple Wood
Flour, Grade 10010 and Pine Wood Flour, Grade 10020, both of which
are commercially available from American Wood Fibers (Columbia,
Md.).
[0080] A specific example of a nylon powder suitable for use as a
filler herein is Morton Corvel White Nylon 11 powder which is
commercially available from the Morton International Incorporation
located in Chicago, Ill.
[0081] A specific example of a polyester powder suitable for use as
a filler herein is Morton Corvel H RF polyester powder which is
commercially available from the Morton International
Incorporation.
[0082] A specific example of a titanium dioxide material suitable
for use as a filler herein is Titanium Dioxide Grade R102 17145T-43
which is commercially available from Dupont White Pigment &
Mineral Products located in Wilmington, Del.
Preferred Embodiments
[0083] The flushable tampon applicators of the present invention
preferably comprise a blend of water-dispersible and biodegradable
materials, wherein this blend can be defined as a combination of
one or more high molecular weight polyethylene oxides, one or more
low molecular weight polyethylene glycols, and one or more
aliphatic/aromatic copolyesters. In this context, the term "blend"
refers to a composition of thermoplastic materials that has been
formed by melt processing two or more thermoplastic materials to
result in a homogenous, heterogeneous, or mixture thereof, of these
materials. It has been found that a thermoplastic blend comprising
a combination of high molecular weight polyethylene oxides, low
molecular weight polyethylene glycols, and aliphatic/aromatic
copolyesters provides a flushable tampon applicator that readily
disintegrates in water, that has improved aesthetics such as
non-sticky, non-slimy, air-laden moisture resistance, softness,
flexibility, and that is of little or no environmental concern for
disposal.
[0084] The combination of the high molecular weight polyethylene
oxides, low molecular weight polyethylene glycols, and
aliphatic/aromatic copolyesters results in a thermoplastic
composition comprising a total of from about 1% to about 90% by
weight of high molecular weight polyethylene oxides, a total of
from about 1% to about 4 0% by weight of low molecular weight
polyethylene glycols, and a total of from about 9% to about 59% by
weight of aliphatic/aromatic copolyesters. Therefore, the
thermoplastic compositions can comprise blended ratios of
water-dispersible materials such as high 20 molecular weight
polyethylene oxides and low molecular weight polyethylene glycols
to biodegradable materials such as aliphatic/aromatic copolyesters
of from about 10:1 to about 1:6, preferably of from about 4:1 to
about 1:3. The ratio of water-dispersible materials, such as a
ratio of high molecular weight polyethylene oxide to low molecular
weight polyethylene glycol, typically ranges from about 9:1 to
about 1:4, preferably from about 3:1 to about 1:2.
[0085] The flushable tampon applicators of the present invention
can also comprise other blends of water-dispersible and
biodegradable thermoplastic polymers, nonlimiting examples of which
include a blend of one or more high molecular weight polyethylene
oxides, one or more low molecular weight polyethylene glycols, and
one or more diacid/diol-based aliphatic polyesters; a blend of one
or more high molecular weight polyethylene oxides, one or more low
molecular weight polyethylene glycols, and one or more aliphatic
polyesteramides; and a blend of one or more high molecular weight
polyethylene oxides, one or more low molecular weight polyethylene
glycols, and one or more polylactic acid polymers. These blends as
well as the above-described preferred thermoplastic polymer blend
and any other blend or structure of thermoplastic materials are
suitable for forming the outer tubular member and plunger
components of the flushable tampon applicators of the present
invention.
[0086] The flushable tampon applicators of the present invention
can also comprise a composite of thermoplastic materials. In this
context, the term "composite" refers to a structure of
thermoplastic polymeric materials that are intermingled together or
joined such that each thermoplastic polymer forms at least one unit
of the total composite structure. For example, a thermoplastic
composite can contain one or more units of water-dispersible
polymers intermixed or joined with one or more units of
biodegradable polymers such that within the overall composite
structure the water-dispersible polymer units create structural
discontinuities between the biodegradable polymer units. In this
context, the term "structural discontinuities" refers to discrete
or separate components that are joined or intermingled to provide
adjacent or alternate units of individual components. Preferably, a
thermoplastic composite is constructed such that it comprises less
than about 99% of water-dispersible polymers and more than about 1%
of biodegradable polymers, more preferably less than about 95% of
water-dispersible polymers and more than about 5% of biodegradable
polymers, even more preferably less than about 90% of
water-dispersible polymers and more than about 10% of biodegradable
polymers, by weight of the composite. However, the thermoplastic
composites can be any composite combination of water-dispersible
and biodegradable polymers described herein provided that the
water-dispersible polymers allow for rapid dispersion of the
biodegradable polymers into separate components so that the overall
composite structure readily disintegrates upon contact with water.
The thermoplastic composite tampon applicators can be constructed
using known procedures such as injection molding and co-injection
molding which eliminate the need to assemble separate composite
pieces for producing a final tampon applicator product.
Alternatively, the thermoplastic composite tampon applicators can
be constructed by molding separate composite pieces and assembling
or joining the pieces into a final tampon applicator product,
wherein means of assembling or joining the composite pieces include
adhesive bonding, heat sealing, ultrasonic welding, solvent
welding, dielectric sealing, and mechanical attachment. The
flushable tampon applicators of the present invention made from
thermoplastic composites have been found to be readily disposed of
by flushing down a sewage system such as a toilet and by the
disclosed biodegradation procedures. The composite tampon
applicators can also be made from a composite structure of
thermoplastic polymers combined with paper, cellulose, cellophane,
rayon fiber, woven, nonwoven materials, or combinations
thereof.
[0087] It is contemplated that the flushable tampon applicators of
the present invention can be constructed 30 in any other blend,
composite, shape, or configuration using the water-dispersible
and/or biodegradable thermoplastic polymers, and any other desired
or optional ingredient described herein. Another nonlimiting
preferred embodiment includes spiral shaped flushable tampon
applicators made from spirally wound thermoplastic materials that
are held together using water-soluble adhesives. The water-soluble
adhesive materials may be any known or otherwise effective
water-soluble adhesives, but preferably are polyethyloxazoline and
methyl cellulose adhesives.
[0088] The flushable tampon applicators of the present invention
can also comprise a composite of thermoplastic material and a
non-thermoplastic material wherein the non-thermoplastic material
is selected from the group including paper, starch, cellulose,
cellophane, rayon fiber, natural fiber fabrics either woven or
nonwoven, and combinations thereof. The thermoplastic material may
be combined with the non-thermoplastic material by various
techniques such as overmolding or insert molding. In overmolding,
the non-thermoplastic material, for example a paper tube, is placed
into an injection mold cavity, the mold clamped shut, and a molten
thermoplastic resin is injected into the cavity such that the
non-thermoplastic material is encapsulated or partly encapsulated
by the thermoplastic material. In a tampon applicator, overmolding
can provide, for example, a means of providing plastic-like
features to a paper tube, or providing the look and feel of a
plastic applicator to a paper tube, or providing a means of
minimizing the amount of thermoplastic material needed to form the
applicator components. Both inner and outer tube members may be
fabricated from a composite of thermoplastic material and a
non-thermoplastic material. In insert molding, the
non-thermoplastic material is typically provided in a roll,
unwound, and then trimmed or formed to a proper preform size and
shape appropriate to insertion into the injection mold. The perform
(or performs) is placed, along the wall of the mold cavity. The
mold is then clamped shut, and the thermoplastic material injected
into the mold cavity. Heat and pressure conditions in the mold
cavity bond the perform to the thermoplastic resin. Bonding between
the thermoplastic material perform may occur through mechanical
entanglement, adhesion, or via melt bonding or fusion if the
surface of the non-thermoplastic material has been pre-treated with
a meltable surface coating. The preform comprising the
non-thermoplastic material, generally becomes the surface or part
of the surface of the finished molded part. In a tampon applicator,
insert molding can provide, for example, a means of attaching a
thin, water-insoluble, biodegradable surface layer to a
water-softenable or water-dispersable, or water-degradable, or
water-soluble thermoplastic resin.
[0089] Still yet another nonlimiting embodiment of flushable tampon
applicators include a composite flushable tampon applicator made
from a combination of water-dispersible thermoplastic polymers,
biodegradable thermoplastic polymers, and filler. These composite
applicator structures are less tacky when wet, non-sticky when wet,
softer, and more flexible than plastic tampon applicators made
without filler components. The filler-containing composite
applicators also result in reduced manufacturing cost with improved
processibility of the applicators. Any suitable inorganic and/or
organic filler component can be included in the construction of the
composite applicator, provided that during the processing of the
applicator the filler does not melt and remain in its particle
form. Typically, the processing temperatures are lower than the
melting temperature and decomposition temperature of the fillers,
and during processing the water-dispersible and biodegradable
thermoplastic polymers are melted and the filler particles are
uniformly dispersed in the matrix of polymer blends of the
water-dispersible and biodegradable polymers to result in the
formation of a composite structure. The fillers suitable for use
herein generally are water insoluble which help to reduce the
stickiness of the applicators upon contact of the applicators with
water, and which help to increase the shelf stability of the
applicators. Also, because the fillers are in the dispersed phase
of the composite, they accelerate the disintegration rate when the
matrix of polymer blends of water-dispersible and biodegradable
polymers start to disintegrate after flushing into a sewage system
such as a toilet.
[0090] It is preferred that the flushable tampon applicators of the
present invention be constructed from thermoplastic materials that
are typically in the form of polymer films. It should be
understood, however, that these thermoplastic materials are also
suitable for use as fibrous materials in the construction of
absorbent articles such as tampon pledgets or any other fibrous or
nonwoven material.
Composition Morphology
[0091] Thermoplastic compositions suitable for use in the
manufacture of flushable tampon applicators of the present
invention can be a blend or other configuration of polymeric
materials which will result in the compositions exhibiting
amorphous and crystalline properties that can be characterized in
terms of compositional morphology. It has been found that a
particular blend of water-dispersible and biodegradable polymers
described herein results in a thermoplastic composition having a
defined morphology which provides for individual components of the
composition to have melt profiles that allows for the creation of
crystalline structures in the form of separate regions or domains
within the blended nmixture of thermoplastic materials.
Specifically, it has been found that a thermoplastic composition
comprising a blend of high molecular weight polyethylene oxides,
low molecular weight polyethylene glycols, and aliphatic
polyesteramides or aliphatic/aromatic copolyesters exhibits a
morphology such that the polyethylene oxides and polyethylene
glycols form a homogenous blend of water-dispersible polymers that
surrounds or encloses microdomains of the aliphatic polyesteramides
or aliphatic/aromatic polyesters. In this context the term
"microdomain" refers to polymer crystalline structures that have
particle sizes in the submicron to micron sized region. It has also
been found that a thermoplastic composition comprising a blend of
water dispersible polymers such as high molecular weight
polyethylene oxides and/or low molecular weight polyethylene
glycols in combination with biodegradable polymers such as
diacids/diols aliphatic polyesters forms a homogeneous one-phase
polymer morphology.
[0092] The two phase crystalline structure of a continuous phase of
water-dispersible polymers and a discontinuous phase of
biodegradable polymer microdomains are especially effective in
forming thermoplastic compositions that can be melt processed into
flushable tampon applicators of the present invention which are
readily disposed of without creating any environmental concerns for
their disposal. The two-phase crystalline structure has a
morphology profile of water-dispersible and biodegradable polymers
wherein in the liquid state (temperature above the melting point of
the individual polymers), the polymers exhibit a heterogeneous
phase morphology, but can be melt processed to result in a solid
flushable tampon applicator exhibiting homogenous properties.
Therefore, as used herein the term "homogenous" refers to a uniform
mixture of materials, whereas the term "heterogeneous" refers to a
nonuniform mixture of materials. The phase morphology can be
determined using optical and scanning electron microscopes, for
example a convenient optical microscopy instrument that can be used
to determine the phase morphology of the thermoplastic compositions
described herein is the Zeiss Axioplan 2 Mot-Imaging Microscope
that is equipped with a Linkham MDS-BCS-600 hot stage and that is
available from the Carl Zeiss Incorporation located in Thornwood,
N.Y.
[0093] The phase morphology of the water-dispersible and
biodegradable polymers defined herein can further be described in
terms of the polymers glass transition temperatures (T.sub.g). The
glass transition temperature of polymers or any other materials is
typically identified as the area on the line where a distinct
change in slope occurs, and can be determined using a thermal
analysis instrument such as the 2980 Dynamic Mechanical Analyzer
(DMA) in combination with Thermal Analyst Data Collection software
program (Thermal Solutions version 2.5) and Data Analysis software
program (Universal Analysis version 2.5H), all of which are
available from T. A. Instruments Incorporation of New Castle,
Delaware. It has also been found that combinations of
water-dispersible and biodegradable polymers exhibit one or two
glass transition temperatures, providing further support of
polymers having one- or two-phase morphology profiles. As
exemplified in Table 1 hereinbelow, polymer blends of
water-dispersible polymers and aliphatic polyesteramides exhibit
two different glass transition temperatures indicative of a
two-phase morphology wherein polymer blends of water-dispersible
polymers and diacids/diols aliphatic polyesters exhibit one glass
transition temperature indicative of a one-phase morphology.
[0094] It is believed that these morphology properties will also be
exhibited in thermoplastic compositions made from a composite or
any other configuration of water dispersible and biodegradable
polymers described herein.
1TABLE 1 Glass Transition Behavior of
Water-Dispersible/Biodegradable Polymers and Polymer Blends
Tg.sub.1 Tg.sub.2 Tg.sub.3 Polymers (.degree. C.) (.degree. C.)
(.degree. C.) PEO.sup.1 -41 -- -- PEO.sup.1/PEG.sup.2-40/30 blend
-33 -- -- aliphatic polyesteramide (BAK 404).sup.3 -- -7 --
aliphatic-aromatic copolyester (Eastar 14776).sup.4 -- -25 --
diacid-diol aliphatic polyester (Bionolle 3001).sup.5 -- -31 --
PEO.sup.1/BAK 404.sup.3-75/25 blend -43 8 -- PEO.sup.1/Eastar
14776.sup.4-60/40 blend -42 -24 -- PEO.sup.1/Bionolle
3001.sup.5-70/30 blend -- -- -36 PEO.sup.1/Bionolle
3001.sup.5-50/50 blend -- -- -28 PEO.sup.1/Bionolle
3001.sup.5-15/85 blend -- -- -30 PEO.sup.1/PEG.sup.2/BAK
404.sup.3-40/30/30 blend -31 -10 -- PEO.sup.1/PEG.sup.2/Eastar
14776.sup.4-40/30/30 blend -41 -27 -- PEO.sup.1/PEG.sup.2/Bionolle
3001.sup.5-40/30/30 blend -- -- -31 Tg.sub.1-glass transition
temperature of water-dispersible polymer(s) Tg.sub.2-glass
transition temperature of biodegradable polymer Tg.sub.3-combined
glass transition temperature of water-dispersible and biodegradable
polymers .sup.1polyethylene oxide available as POLYOX .RTM. WSR-80
from the Union Carbide Corporation .sup.2polyethylene glycol
available as PEG-8000 from Union Carbide .sup.3aliphatic
polyesteramide available as BAK 404 from Bayer Aktiengesellschaft
.sup.4aliphatic-aromatic copolyester available as Eastar
Biodegradable Copolyester 14776 from Eastman Chemical
.sup.5diacid-diol aliphatic polyester available as BIONOLLE 3001
from the Showa Highpolymer Company, Ltd.
Physical Properties
[0095] The flushable tampon applicators of the present invention
are made from thermoplastic compositions having physical properties
of tensile strength at break, percent elongation at break, elastic
modulus, and hardness. The thermoplastic compositions can include
ingredients such as fillers, plasticizers, processing aids,
dispersing agents, lubricants, resin modifiers,
clarifying/nucleating agents, viscosity modifiers, and the like.
Preferred thermoplastic compositions comprise water-dispersible
thermoplastic polymers, biodegradable thermoplastic polymers,
plasticizers, and/or lubricants, and/or fillers in various
combinations.
[0096] The tensile strength at break, percent elongation at break,
and elastic modulus of thermoplastic materials, especially blends
of thermoplastic materials, are determined according to methods
known in the art. One such method is the ASTM D882-95a test method
described in "Standard Test Method for Tensile Properties of Thin
Plastic Sheeting", pages 159-167. This procedure involves testing
blends of thermoplastic materials for achieving desired properties
of flexibility, elasticity, durability, unbrittleness, resilency,
distensibility, tenacity, and so forth. Typically, blends of
thermoplastic materials are injection molded to form
"dogbone-shaped" test samples having dimensions of 1/2 inch length
(L).times.1/8 inch width (W).times.{fraction (1/16)} inch height
(H), then the "dogbone-shaped" test samples are evaluated for
tensile strength at break, percent elongation at break, and elastic
modulus using an Instron Tensile Tester (Model 1122 from Instron
Corporation located in Canton, Mass.) equipped with a 50 pound load
cell, grip separation of 1 inch, a gage length of 1/2 inches, 5
millimeter (mm) jaw gap, and a crosshead speed of 2 inches/minute.
For each analysis, the "dogbone-shaped" test sample is stretched
until breakage occurs, and a load-versus-extension plot is
generated for determining the tensile strength at break, percent
elongation at break, and elastic modulus properties. The tensile
strength at break is the load at break divided by the
cross-sectional area of the test sample, and is defined in units of
mega-Pascal or MPa (newton/square meter). The percent elongation at
break is determined by dividing the length of the extension at the
point of rupture by the gage length, and then multiplying by 100.
Elastic modulus is the slope of the initial linear portion of the
load-extension curve, and is defined in units of MPa.
[0097] The thermoplastic compositions described herein preferably
have a harness property such that the compositions exhibit a firm
resistance to stress or strain, yet are not brittle or too soft for
processing into flushable tampon applicators of the present
invention. The hardness properties are determined according to ASTM
D2240-97 test method described in "Standard Test Method for Rubber
Property-Durometer Hardness, pages 388-391. Typically,
thermoplastic materials are injected molded into bars that are
stacked in groups of two bars per stack wherein each bar stack has
a total thickness of 1/8 inches. The hardness value is measured at
various points of the bar stack using a hardness instrument such as
Model 307 L Shore D Durometer from PTC Instruments, and a mean
hardness measurement is determined.
[0098] The preferred thermoplastic compositions for constructing
the flushable tampon applicators of the present invention have
physical properties similar to or superior to physical properties
of known thermoplastic materials that are used in the manufacture
of tampon applicators. For example, polyethylene-based
thermoplastic polymers typically have elastic modulus properties of
from about 80 MPa to about 200 MPa, wherein other thermoplastic
polymers such as polypropylene-based polymers have elastic modulus
of from about 1000 MPa to about 1500 MPa. It has been found that
the thermoplastic compositions described herein exhibit desirable
properties of an elastic modulus value of less than 1000 MPa, and
this elastic modulus attribute in addition to the other described
physical properties result in thermoplastic compositions having
flexibility, elasticity, durability, resilency, distensibility,
tenacity, and the like. The physical properties of the preferred
thermoplastic compositions are exemplified hereinbelow in Table
2.
2TABLE 2 Thermoplastic Compositions Physical Properties Tensile
Percent Strength Elongation Elastic at break at break Modulus
Hardness Sample (MPa) (%) (MPa) (Shore D)
PEO.sup.1/PEG.sup.2/Biomer 209H.sup.6 (40/30/30 blend) 6 20 310 58
PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 (40/30/30 blend) 8 460 220
51 PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 (66/17/17 blend) 5 80
270 52 PEO.sup.1/PEG.sup.2/Eastar 14776.sup.4 (40/30/30 blend) 6 80
230 51 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/30/30 blend) 11 20 250
57 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/40/20 blend) 9 20 340 60
PEO.sup.1/PEG.sup.2/BAK.sup- .3/P-645.sup.7 (36/27/27/10 blend) 8
46 190 51 PEO.sup.1/PEG.sup.2/BAK.sup.3/P-4141.sup.8 (36/27/27/10
blend) 7 48 180 51 PEO.sup.1/PEG.sup.2/PLA 44D.sup.9 (40/30/30
blend) 19 13 530 67 PEO.sup.1/PEG.sup.2/PLA 62-50D.sup.9 (40/30/30
blend) 22 10 510 67
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.sup- .10
(11/9/20/10/50 blend) 3 27 90 43 PEO.sup.1/PEG.sup.2/Eastar.su-
p.4/P-645.sup.7/CaCO.sub.3.sup.10 (24/18/18/10/30 blend) 5 60 166
49 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.sup.10
(29/21/10/10/30 blend) 4 18 227 52 PEG.sup.2/PEG.sup.11/Eastar.sup-
.4/P-645.sup.7/CaCO.sub.3.sup.10 (20/5/40/5/30 blend) 6 12 174 48
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.sup.10
(16/12/12/10/50 blend) 5 13 184 47 PEO.sup.1/PEG.sup.2/Eastar.sup.-
4/P-645.sup.7/Talc.sup.12 (17/13/10/10/50 blend) 5 16 173 43
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/Talc.sup.12
(24/18/18/10/30 blend) 4 40 303 47
PEO.sup.1/PEG.sup.2/Eastar.sup.4/AB.sup.13/wood
flour.sup.14/TiO.sub.2.sup.15/Kemamide E.sup.16 17 5 640 61
(17/17/25/5/30/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/Starch.-
sup.17/P-645.sup.7/Kemamide E.sup.16 2 22 98 34 (18/13/13/50/5/1
blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/Starch.sup.18/P-645.sup.7/-
Kemamide E.sup.16/MgSt.sup.19 4 180 160 46 (15/10/37/30/5/1/2
blend) PEO.sup.1/Eastar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7
(18/15/65/4 blend) 7 58 230 53 PEO.sup.1/PEG.sup.2/Eastar.sup.4/Ca-
CO.sub.3.sup.10/P-645.sup.7/Kemamide E.sup.16 6 95 180 49
(15/10/29/40/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.-
3.sup.10/P-645.sup.7/MgSt.sup.19/Loxiol G33.sup.20 5 310 160 43
(15/10/26/40/5/2/2 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.su-
b.3.sup.10/P-645.sup.7/Kemamide E.sup.16 8 450 180 49
(15/10/39/30/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.-
3.sup.10/P-645.sup.7/Kemamide E.sup.16/Paraffin 5 340 140 42
wax.sup.21 (15/10/34/30/5/1/5 blend) PEO.sup.1/Eastar.sup.4/CaCO.s-
ub.3.sup.10/P-645.sup.7/Kemamide E.sup.16 10 640 83 44
(25/39/30/5/1 blend) PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/MgSt-
.sup.19 (17.5/64/17.5/1 blend) 6 650 150 46
PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/MgSt.sup.19/P-643.sup.22/DC4-705-
1.sup.25 10 1040 68 37 (15/62/15/1/5/2 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7/MgSt.sup.1-
9/DC9506.sup.23 5 130 150 44 (15/10/26/40/5/2/2 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO3.sup.10/P-645.sup.7/MgSt.sup.19/Lox-
iol 5 130 150 44 G33.sup.20/Kraton G 1652.sup.24
(14.5/9.5/25.5/39.5/5/2/2/2 blend) .sup.6polyhydroxyalkano- ate
available as Biomer 209H from Biomer, Frost-Kasten-Str., Krailling,
Germany .sup.7adipate polyester plasticizer available as Plasthall
645 from C. P. Hall .sup.8triethylene glycol caprate-caprylate
plasticizer available as Plasthall 4141 from C. P. Hall
.sup.9polylactic acids available as PLA 44D grade and PLA 62-50D
grade from Cargill-Dow Polymers, LLC .sup.10calcium carbonate
available as Vicron 15-15 from Specialty Mineral
.sup.11polyethylene glycol available as PEG-600 from Union Carbide
.sup.12talc available as ABT 2500 from Specialty Mineral .sup.13AB
anti-block processing aid available from Eastman Chemical
.sup.14pine wood flour available as Pine Wood Flour Grade 10020
from American Wood Fibers .sup.15titanium dioxide available from
DuPont White Pigment & Mineral Products .sup.16euracamide
available as Kemamide E Ultra from Crompton Corpration .sup.17Food
grade corn starch available as Staley Pure Food Powdered from A. E.
Staley Manufacturing Co. .sup.18Food grade corn starch available as
National Starch Melojel from National Starch & Chemical
.sup.19Magnesium Stearate available from Aldrich Chemical Company
.sup.20ester wax of fatty acid and fatty alcohol available as
Loxiol G33 from Cognis Plastics Technology .sup.21paraffinic
hydrocarbon wax available as Paraflint H-1 from Moore & Munger
Inc .sup.22adipate polyester plasticizer available as Plasthall 643
from C. P. Hall .sup.23silicone elastomer powder available as DC
9506 from Dow Corning .sup.24SEBS, tri-block copolymer of styrene
and ethylene-butylene with poly(ethylene-butylene) in the center
available as Kraton G 1652 from Kraton Polymers .sup.25silicone
resin modifier available as DC4-7051 from Dow Corning
[0099] The thermoplastic compositions also have physical properties
of dry and wet flexural modulus. The dry flexural modulus is
determined according to ASTM D5943-96 test method described in
"Standard Test Method for Determining Flexural Properties of
Plastics", pages 708-712. This procedure involves injection molding
thermoplastic materials into "beams" of test samples having 5 inch
L.times.1/2 inch W.times.1/8 inch H. Generally, the test samples
are pre-loaded with 0.01 pounds of force, thereafter a force
loading is applied at a rate of 0.1 inches per minute, and a
stress-versus-strain curve is generated to determine the dry
flexural modulus property. The dry flexural modulus is the slope of
the stress-strain curve as calculated in the linear region of from
about 0.05% to about 0.25% of the flexural strain. The wet flexural
modulus is determined by submerging the dry "beams" of test samples
in water at time intervals of 5 minutes, 15 minutes, and 60
minutes, and observing the softening of the test samples. As used
herein, the term "softening" refers to materials that readily lose
their stiffness or undergo a decrease in flexural modulus property
upon contact with water. It has been found that the preferred
thermoplastic compositions described herein undergo a significant
decrease in flexural modulus upon contact of the composition with
water. This decrease in flexural modulus property provides for
thermoplastic compositions that are manufactured into flushable
tampon applicators that readily lose their structural integrity in
water for easy disposal down a sewage system such as a toilet. Dry
and wet flexural modulus properties of preferred thermoplastic
compositions are exemplified hereinbelow in Table 3.
3TABLE 3 Flexural Modulus Physical Properties Wet Wet Wet Dry
Flexural Flexural Flexural Flexural Modulus Modulus Modulus Modulus
(MPa) (MPa) (MPa) Sample (MPa) at 5 min. at 15 min. at 60 min.
PEO.sup.1/PEG.sup.2/Biomer 209H.sup.6 (40/30/30 blend) 700 290 140
40 PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 (40/30/30 blend) 540 180
140 30 PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 (66/17/17 blend) 450
190 150 50 PEO.sup.1/PEG.sup.2/Eastar 14776.sup.4 (40/30/30 blend)
610 180 120 20 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/30/30 blend)
720 210 100 40 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/40/20 blend)
840 450 300 60 PEO.sup.1/PEG.sup.2/BAK.sup.3/P-645.sup.7
(36/27/27/10 blend) 360 230 150 30 PEO.sup.1/PEG.sup.2/BAK.sup.3/P-
-4141.sup.8 (36/27/27/10 blend) 350 220 120 40
PEO.sup.1/PEG.sup.2/PLA 44D.sup.9 (40/30/30 blend) 1280 700 430 260
PEO.sup.1/PEG.sup.2/PLA 62-50D.sup.9 (40/30/30 blend) 1220 660 450
220 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO3.sup.10
(11/9/20/10/50 blend) 206 154 106 42 PEO.sup.1/PEG.sup.2/Eastar.su-
p.4/P-645.sup.7/CaCO3.sup.10 (24/18/18/10/30 blend) 377 211 181 61
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO3.sup.10
(29/21/10/10/30 blend) 549 211 163 28
PEG.sup.2/PEG.sup.11/Eastar.sup.4/P-645.sup.- 7/CaCO3.sup.10
(20/5/40/5/30 blend) 292 257 226 210
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO3.sup.10
(16/12/12/10/50 blend) 473 243 182 72
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7- /Talc.sup.12
(17/13/10/10/50 blend) 554 280 246 77
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/Talc.sup.12
(24/18/18/10/30 blend) 745 434 320 140
PEO.sup.1/PEG.sup.2/Eastar.sup.4/AB.sup.13- /wood
flour.sup.14/TiO.sub.2.sup.15/Kemamide E.sup.16 2050 1120 -- 260
(17/17/25/5/30/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/-
Starch.sup.17/P-645.sup.7/Kemamide E.sup.16 330 130 -- 12
(18/13/13/50/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/Starch.su-
p.18/P-645.sup.7/Kemamide E.sup.16/MgSt.sup.19 360 308 211 120
(15/10/37/30/5/1/2 blend) PEO.sup.1/Eastar.sup.4/CaCO.sub.3.sup.10-
/P-645.sup.7 (18/15/65/4 blend) 430 278 177 52
PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7/Kemamide
E.sup.16 390 270 206 83 (15/10/29/40/5/1 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7/MgSt.sup.1-
9/Loxiol G33.sup.20 410 271 203 81 (15/10/26/40/5/2/2 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7/Kemamide
E.sup.16 380 302 234 125 (15/10/39/30/5/1 blend)
PEO.sup.1/Eastar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7/Kemamide
E.sup.16 200 184 179 99 (25/39/30/5/1 blend)
PEO.sup.1/PEG.sup.2/Eas-
tar.sup.4/CaCO.sub.3.sup.10/P-645.sup.7/Kemamide E.sup.16/Paraffin
300 205 187 94 wax.sup.21 (15/10/34/30/5/1/5 blend)
PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/MgSt.sup.19
(17.5/64/17.1/1 blend) 320 263 245 228
PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/M-
gSt.sup.19/P-643.sup.22/DC4-7051.sup.25 140 128 133 116
(15/62/15/1/5/2 blend)
[0100] The thermoplastic compositions also have physical properties
of weight loss in water which can be determined by the percent
weight loss of a dry specimen sample of a thermoplastic composition
that has been submerged in water for time intervals of 5 minutes, 1
hour, 24 hours, and 1 week. For example, dry injection molded
thermoplastic compositions having a thickness of about 1/8 inches
are weighed to ascertain the dry specimens dry weight. The dry
specimens are then soaked in water for a duration of 5 minutes, 1
hour, 24 hours, or 1 week, wherein dependent on the type of
thermoplastic composition dissolution of the water-soaked specimen
occurs. The water-soaked specimens are recovered for drying in a
Blue M oven for 16 hours at 40.degree. C. to obtain a final weight
loss. The percent weight loss is calculated by subtracting the
weight of dried water-soaked specimens minus the dry specimens
initial weight, divided by the dry specimens initial weight, and
multiplied by 100. The percent weight loss values of thermoplastic
compositions described herein are exemplified hereinbelow in Table
4. A negative percent weight loss value is indicative of the
thermoplastic composition being able to readily dissolve or
disintegrate in water, and a positive percent weight loss value is
indicative of the thermoplastic composition being able to maintain
its structural integrity in water and not readily break apart into
unrecognizable pieces. It has been found that the preferred
thermoplastic compositions described herein can be molded into
flushable tampon applicators of the present invention that exhibit
a weight loss in water such that after being submerged for a period
of 5 minutes the tampon applicators are capable or readily breaking
apart, an observation of such tampon applicators being suitable for
disposal by flushing down a toilet. These flushable tampon
applicators exhibited a significant weight loss in water over a
time period of 24 hours.
4TABLE 4 % Weight (Wt.) Loss Physical Property % Wt. % Wt. % Wt. %
Wt. loss loss loss loss (5 min, (1 hour (24 hours (1 week Sample
soaking) soaking) soaking) soaking) PEO.sup.1/PEG.sup.2/Biomer
209H.sup.6 (40/30/30 blend) -4 -22 -69 -87
PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 (40/30/30 blend) -8 -16 -63
-67 PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 (66/17/17 blend) -4 -66
-76 -80 PEO.sup.1/PEG.sup.2/Eastar 14776.sup.4 (40/30/30 blend) -3
-15 -69 -73 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/30/30 blend) -6
-19 -73 -77 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/40/20 blend) -12
-61 -100 -100 PEO.sup.1/PEG.sup.2/BAK.sup.3/P-645.sup.7
(36/27/27/10 blend) 6 -22 -61 -67
PEO.sup.1/PEG.sup.2/BAK.sup.3/P-4141.sup.8 (36/27/27/10 blend) 1
-18 -60 -65 PEO.sup.1/PEG.sup.2/PLA 44D.sup.9 (40/30/30 blend) 3 -7
-51 -56 PEO.sup.1/PEG.sup.2/PLA 62-50D.sup.9 (40/30/30 blend) 1 -11
-52 -56
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.sup.10
(11/9/20/10/50 blend) -2 -8 -11 -21 PEO.sup.1/PEG.sup.2/Eastar.su-
p.4/P-645.sup.7/CaCO.sub.3.sup.10 (24/18/18/10/30 blend) -1 -6 -37
-39 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.sup.10
(29/21/10/10/30 blend) -2 -22 -- -77 PEG.sup.2/PEG.sup.11/Eastar.s-
up.4/P-645.sup.7/CaCO.sub.3.sup.10 (20/5/40/5/30 blend) -3 -6 -18
-20 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.sup.10
(16/12/12/10/50 blend) -2 -10 -34 -35 PEO.sup.1/PEG.sup.2/Eastar.s-
up.4/P-645.sup.7/Talc.sup.12 (17/13/10/10/50 blend) -3 -8 -29 -30
PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/Talc.sup.12
(24/18/18/10/30 blend) 0 -5 -40 -41
Disintegration Rate
[0101] The flushable tampon applicators of the present invention
are constructed of water-dispersible and biodegradable components
to provide for applicators that readily lose their structural
integrity and disintegrate in water, especially in water from a
waste disposal system. It has been shown that the flushable tampon
applicators of the present invention can soften and disintegrate
into unrecognizable pieces in about an hour of exposure to
wastewater. Prolonged exposure which is indicative of municipal
waste disposal means results in further disintegration of these
flushable tampon applicators.
[0102] To test the disintegration rate of a flushable tampon
applicator comprising thermoplastic materials, the applicator is
initially weighed to obtain an initial dry weight, and then the
applicator is exposed to wastewater at time intervals of 1 hour, 6
hours, 24 hours, and 48 hours. Suitable wastewater that can be used
in the disintegration test include influent wastewater that can be
obtained from a municipal waste treatment plant.
[0103] Thermoplastic tampon applicator products and control samples
are each submerged in about one liter of wastewater and allowed to
shake using any suitable rotary floor shaker capable of shaking the
control/wastewater and applicator/wastewater test samples at a
shaker rate of 150 revolutions per minute (rpm). Control samples
which can be used for this disintegration test include about 3-5
grams of fluted or folded Whatman #41 filter paper (i.e., about 3-4
pieces of the filter paper for each control sample).
[0104] After a shaking period of one hour, visual observations of
the test sample are recorded for any noticeable structural
differences in the tampon applicator. After shaking periods of 6
hour, 24 hours, and 48 hours the test sample is filtered using
sieves arranged from top to bottom in the following order: 8
millimeter (mn) sieve, 4 mm sieve, 2 mm sieve, 1 mm sieve, and a
0.5 mm sieve. The remaining solids of the test sample captured on
the 8 mm sieve is then gently rinsed for 5 minutes using a
hand-held showerhead spray nozzle while minimizing the passage of
retained remaining solids to the next smaller sieve. The 8 mm sieve
is removed, and the remaining solids on the next smaller sieve is
rinsed for 5 minutes. The 5 minute rinsing cycle is performed on
each sieve containing retained remaining solids.
[0105] After rinsing, the retained test sample from each sieve is
transferred using forceps or commercial paint brushes to individual
aluminum pans, and the aluminum pans are placed in a Blue M oven at
40.degree. C. to dry overnight. The dried test sample is weighed,
and the retained fraction of each control and applicator product is
determined using the following calculation: 1 % of Retained
Fraction = Dried retained fraction on sieve ( gm ) Initial weight
of sample ( gm ) .times. 100
[0106] It has been found that the tampon applicators of the present
invention readily soften and disintegrate after being submerged in
wastewater for one hour with substantially increased disintegration
after only 6 hours of exposure. These tampon applicators are
suitable for flushing in a sewage system such as a toilet due to
their ability to readily break apart and dissolve in wastewater
produced from toilet septic tanks. Data showing the disintegration
rate of flushable tampon applicators of the present invention is
exemplified hereinbelow.
5 PEO.sup.1/PEG.sup.2/Eastar.sup.4 (40/30/30 blend) 8 mm 4 mm 2 mm
1 mm 0.5 mm Disintegration Rate sieve sieve sieve sieve sieve %
Initial Fraction 100 -- -- -- -- 6 hour % Retained Fraction 40.79
0.00 0.00 0.03 0.08 24 hour % Retained Fraction 30.71 0.19 0.00
0.00 0.10 48 hour % Retained Fraction 32.31 0.00 0.03 0.03 0.07
[0107]
6 PEO.sup.1/PEG.sup.2/BAK 404.sup.3 (40/30/30 blend) 8 mm 4 mm 2 mm
1 mm 0.5 mm Disintegration Rate sieve sieve sieve sieve sieve %
Initial Fraction 100 -- -- -- -- 6 hour % Retained Fraction 10.61
3.89 0.25 0.08 2.33 24 hour % Retained Fraction 7.63 1.91 0.36 0.50
3.43 48 hour % Retained Fraction 4.48 2.09 0.89 0.91 2.62
[0108]
7 PEO/PEG/Bionelle 3001.sup.5 (40/30/30 blend) 8 mm 4 mm 2 mm 1 mm
0.5 mm Disintegration Rate sieve sieve sieve sieve sieve % Initial
Fraction 100 -- -- -- -- 6 hour % Retained Fraction 56.35 0.00 0.00
0.00 0.00 24 hour % Retained Fraction 51.40 0.00 0.00 0.00 0.00 48
hour % Retained Fraction 42.46 0.00 0.00 0.00 0.11
[0109]
8 PEO.sup.1/PEG.sup.2/PLA 44D.sup.9 (40/30/30 blend) 8 mm 4 mm 2 mm
1 mm 0.5 mm Disintegration Rate sieve sieve sieve sieve sieve %
Initial Fraction 100 -- -- -- -- 6 hour % Retained Fraction 2.06
2.96 3.82 5.58 0.07 24 hour % Retained Fraction 1.39 3.58 2.25 3.93
5.06 48 hour % Retained Fraction 2.82 6.56 5.44 5.16 5.32
[0110]
9 PEO.sup.1/PEG.sup.2/Biomer 209H.sup.6 (40/30/30 blend) 8 mm 4 mm
2 mm 1 mm 0.5 mm Disintegration Rate sieve sieve sieve sieve sieve
% Initial Fraction 100 -- -- -- -- 6 hour % Retained Fraction 0.00
0.08 0.00 0.08 0.52 24 hour % Retained Fraction 0.00 0.10 0.04 0.25
0.66 48 hour % Retained Fraction 0.00 0.00 0.00 0.27 1.36
[0111]
10 PEO.sup.1/PEG.sup.2/Eastar.sup.4/AB.sup.13/wood
flour.sup.14/TiO.sub.2.sup.15/Kemamide E.sup.16 (17/17/25/5/30/5/1
blend) 8 mm 4 mm 2 mm 1 mm 0.5 mm Disintegration Rate sieve sieve
sieve sieve sieve % Initial Fraction 100 -- -- -- -- 6 hour %
Retained Fraction 23.54 0.00 0.83 1.26 1.87 24 hour % Retained
Fraction 6.31 2.39 3.34 3.11 3.31 48 hour % Retained Fraction 0.00
3.71 2.75 2.73 3.63
[0112]
11 PEO.sup.1/PEG.sup.2/Eastar.sup.4/Starch.sup.17/P-645.sup-
.7/Kemamide E.sup.16 (18/13/13/50/5/1 blend) 8 mm 4 mm 2 mm 1 mm
0.5 mm Disintegration Rate sieve sieve sieve sieve sieve % Initial
Fraction 100 -- -- -- -- 6 hour % Retained Fraction 4.36 1.56 7.65
4.77 4.53 24 hour % Retained Fraction 0.00 0.64 3.37 6.72 10.88 48
hour % Retained Fraction 0.00 0.00 2.18 5.36 9.14
[0113]
12 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/Talc.sup.12
(24/18/18/10/30 blend) 8 mm 4 mm 2 mm 1 mm 0.5 mm Disintegration
Rate sieve sieve sieve sieve sieve % Initial Fraction 100 -- -- --
-- 6 hour % Retained Fraction 66.68 0.00 0.00 0.00 0.00 24 hour %
Retained Fraction 57.24 0.00 1.17 0.47 0.30 48 hour % Retained
Fraction 55.44 0.19 1.86 1.03 0.97
[0114]
13 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.- sup.10
(11/9/20/10/50 blend) 8 mm 4 mm 2 mm 1 mm 0.5 mm Disintegration
Rate sieve sieve sieve sieve sieve % Initial Fraction 100 -- -- --
-- 6 hour % Retained Fraction 5.25 5.41 21.32 12.08 3.94 24 hour %
Retained Fraction 2.73 2.51 7.09 16.71 10.51 48 hour % Retained
Fraction 0.00 0.89 4.67 8.83 11.53
[0115]
14 PEO.sup.1/PEG.sup.2/Eastar.sup.4/P-645.sup.7/CaCO.sub.3.- sup.10
(24/18/18/10/30 blend) 8 mm 4 mm 2 mm 1 mm 0.5 mm Disintegration
Rate sieve sieve sieve sieve sieve % Initial Fraction 100 -- -- --
-- 6 hour % Retained Fraction 9.72 12.69 20.19 4.17 2.35 24 hour %
Retained Fraction 2.17 3.90 16.02 12.87 3.53 48 hour % Retained
Fraction 0.00 13.41 11.36 9.52 3.19
Optional Components
[0116] The flushable tampon applicators of the present invention
can comprise optional ingredients in combination with the
water-dispersible and biodegradable components wherein the optional
ingredients provide benefits to the final product or to the
thermoplastic materials used in making the final product. Such
benefits include, but are not limited to, stability including
oxidative stability, brightness, flexibility, resiliency,
toughness, workability, odor control, improved strength, improved
modulus, improved melt flow characteristics, and/or distensibility
of the thermoplastic compositions. The flushable tampon applicators
typically comprise from about 0.05% to about 25% of optional
ingredients by weight of the applicator. The optional ingredients
include plasticizing agents, antioxidants, slip agents, optical
brighteners, crystallization accelerators or retarders, flow
promoters, processing aids, pigments or colorants, mold release
agents, nucleating agents, coating agents, gelling agents,
antistatic agents, dispersing agents, compatibilizers, lubricants,
surfactants, heat stabilizers including magnesium stearate, odor
masking agents, opacifying agents such as aluminum oxide, dyes,
viscosity modifiers, ester waxes, elastomers, and mixtures thereof.
The optional plasticizing agents, coating agents, viscosity
modifiers, and lubricants, are described in detail hereinbelow.
[0117] A specific example of a slip agent is Kemamide E Ultra which
is commercially available from the Crompton Corporation (Taft, Los
Angeles).
[0118] pecific examples of optional processing aids include, but
are not limited to, the acrylic polymers commercially available
from the ATOFINA Chemicals Incorporation (Philadelphia, Pa.) under
the Metablen P-550, Metablen P-710 SD, and Metablen C-303
tradenames.
[0119] Specific examples of optional nucleating agents include, but
are not limited to, Licomont CaV 102 and Licomont NaV 101, both of
which are commercially available from the Clariant Corporation
(Coventry, R.I.); and Millad 3988 which is commercially available
from Milliken Chemical (Inman, S.C.).
[0120] A specific example of an optional heat stabilizer is
Thermolite 890S which is commercially available from the ATOFINA
Chemicals Incorporation.
[0121] Specific examples of optional elastomers include, but are
not limited to, Kraton L207, Kraton L1203, Kraton L2203, and Kraton
G 1652, all of which are commercially available from Kraton
Polymers (Houston, Tex.).
[0122] Optional Plasticizing Agent
[0123] If a plasticizing agent is included with thermoplastic
polymers for making the flushable tampon applicators of the present
invention, the plasticizer is included at concentrations ranging
from about 1% to 20 about 25% by weight of the applicator. In this
context, the term "plasticizing agent" refers to any organic
compound that, when added to a thermoplastic polymer, can provide
modification to the polymer's morphology to result in increased
ease of processing of the polymer and increased toughness and
flexibility of the polymer after processing. Examples of optional
plasticizing agents include glycerin, glycerin derivatives such as
triacetin and glycerol monostearate, sorbitol, eritol, glucidol,
mannitol, sucrose, ethylene glycol, propylene glycol, diethylene
glycol, triethylene glycol, diethylene glycol dibenzoate,
dipropylene glycol dibenzoate, triethylene glycol
caprate-caprylate, butylene glycol, pentamethylene glycol,
hexamethylene glycol, diisobutyl adipate, oleic amide, erucic
amide, pannitic amide, dimethyl acetamide, dimethyl sulfoxide,
methyl pyrrolidone, tetramethylene sulfone, oxa monoacids, oxa
diacids, polyoxa diacids, diglycolic acids, triethyl citrate,
acetyl triethyl citrate, tri-n-butyl citrate, acetyl tri-n-butyl
citrate, acetyl tri-n-hexyl citrate, alkyl lactates, phthalate
polyesters excluding the aromatic terephthalate polyesters suitable
for use as a biodegradable polymer herein, adipate polyesters,
glutate polyesters, diisononyl phthalate, diisodecyl phthalate,
dihexyl phthalate, alkyl alylether diester adipate,
dibutoxyethoxyethyl adipate, and mixtures thereof.
[0124] Examples of commercially available plasticizers include the
adipate polyesters sold under the Plasthall P-645, Plasthall P-643,
Plasthall HA7A, Paraplex G-54, and Paraplex G-50 tradenames;
triethylene glycol caprate-caprylate sold under the Plasthall 4141
tradename; the polyesters sold under the Paraplex A-8200 and
Paraplex A-8040 tradenames; the polyester glutarate sold under the
Plasthall P-550 tradename; diisononyl phthalate sold under the
Plasthall DINP tradename; dibutoxyethoxyethyl adipate sold under
the Plasthall 226 tradename; and the Supermix Plasthall 226 and
Supermix Paraplex G-50; all of which are available from the C. P.
Hall Corporation (Chicago, Ill.).
[0125] Optional Coating Agent
[0126] The flushable tampon applicators of the present invention
preferably comprise from about 0.05% to about 10% of a coating
agent by weight of the applicator. The coating agent provides
stability to the final applicator product by serving as a moisture
barrier, and is considered to be effective in reducing or
eliminating the sticky or slippery film feel that can occur when
the applicator comes in contact with air-laden or human moisture.
The coating agent can be applied using any suitable coating
technique known in the art for effectively applying a coating
material on the outer or exterior surface of a thermoplastic
material used to form a flushable tampon applicator. Some known
effective coating methods can be typically described as tumbling
coating, spray coating, brushing, dip coating, slot coating,
gravure coating, extrusion coating, co-extrusion coating, and the
like.
[0127] While the coating material can be applied directly to the
outer or exterior surface of a thermoplastic material described
herein, the coating material can also be applied as a coating
solution. The coating solution comprises the coating solubilized in
a volatile solvent, wherein suitable volatile solvents include
saturated and unsaturated hydrocarbons such as heptane,
cyclohexane, and toluene; halogenated hydrocarbons such as
chlorobenzene, chloroform, and methylene chloride; hydrocarbon
alcohol ethers; and mixtures thereof.
[0128] Optional preferred coating agents suitable for use herein
include waxes, hydrogenated vegetable oils, food grade shellac,
epoxy resins, vinylidene chloride copolymer latexes, polysiloxanes,
sucrose fatty acid esters, and mixtures thereof. A specific example
of a vinylidene chloride copolymer latex is Daran SL 143 which is
commercially available from the Hampshire Chemical Corporation.
[0129] Specific nonlimiting examples of waxes suitable for use as
an optional preferred coating agent include animal waxes (e.g.,
beeswax, spermaceti, lanolin, and shellac wax); vegetable waxes
(e.g., carnauba, candelilla, bayberry, and sugar cane); mineral
waxes (e.g., fossil or earth waxes such as ozokerite, ceresin, and
montan, or petroleum waxes such as paraffin, microcrystalline,
petrolatum, slack and scale wax); chlorinated naphthalenes (e.g.,
"Halowax"); and mixtures thereof. A specific example of a paraffin
wax is Paraflint H-1 which is commercially available from the Moore
& Munger Incorporation located in Shelton, Conn.
[0130] Optional Viscosity Modifiers
[0131] The flushable tampon applicators of the present invention
can optionally comprise viscosity modifiers to increase the
viscosity of the water-dispersible and biodegradable thermoplastic
polymers described herein so that they can be molded using a
preferred injection molding or any other molding technique
described herein. Such viscosity modifiers are typically included
at concentrations ranging from about 0.1% to about 5%, preferably
from about 0.1% to about 2% by weight of the applicator. Nonlimitng
examples of suitable viscosity modifiers include trifunctional
alcohols such as trimethylolpropane, tetrafunctional alcohols such
as pentaerythritol, trifunctional carboxylic acids such as citric
acid, and the like.
[0132] Optional Lubricants
[0133] The flushable tampon applicators of the present invention
can optionally comprise lubricants to increase the overall rate of
processing and to improve surface properties. Therefore, lubricants
are also referred to as mold release agents and slip/anti-blocking
agents, and provide for improved product properties such as
brightness, heat stability during processing, light stability,
better dispersion of additives, and improved optical and mechanical
properties). It is believed that the optional lubricants provide
these processing and product surface properties due to the
migration of the lubricants to the surface of the processed
products where they resist adhesion to processing equipment.
[0134] Examples of optional lubricants suitable for use herein
include, but are not limited to, metal soaps (e.g., stearate
soaps), hydrocarbon waxes including polyethylene wax, fatty acids,
long-chain alcohols, fatty acid esters (e.g., ester waxes), fatty
acid amides, silicones, fluorochemicals, acrylics, and mixtures
thereof.
[0135] Specific examples of metal soaps suitable for use as an
optional lubricant herein include, but are not limited to, calcium
stearate commercially available from the Ferro Corporation
(Cleveland, Ohio,) under the Synpro Calcium Stearate 392A
tradename; magnesium stearate commercially available from the
Aldrich Chemical Company (Milwaukee, Wis.); and the stearates
commercially available from the Norac Incorporation (Helena, Ark.)
such as calcium stearate commercially available under the COAD10
and COAD10LD tradenames, zinc stearate commercially available under
the COAD21 and COAD23 tradenames, and magnesium stearate
commercially available under the MATBHE magnesium stearate
tradename.
[0136] Specific examples of fatty acid esters suitable for use as
an optional lubricant herein include, but are not limited to, the
fatty acid esters commercially available from Cognis-Plastics
Technology (Amber, Pa.) under the Loxiol G33, Loxiol G60, Loxiol
G71S, and Loxiol HOB7111 tradenames; the ester waxes commercially
available from the Clariant Corporation under the Licowax E,
Licolub WE 4, and Licowax OP tradenames; and the ester waxes
commercially available from the Fanning Corporation under the
Natralube 120 and Natralube 125 tradenames.
[0137] Specific examples of silicones suitable for use as an
optional lubricant herein include, but are not limited to, the
silicones commercially available from the Dow Corning Corporation
(Midland, Mich.) under the Dow Corning MB50-002, Dow Corning
MB50-010, Dow Corning 4-7051, and Dow Corning 9506 tradenames.
[0138] Specific examples of fluorochemicals suitable for use as an
optional lubricant herein include, but are not limited to, the
fluoropolymers commercially available from the AG Fluoropolymers
Incorporation (Downingtown, Pa.) under the Whitcon Tl-5 and Whitcon
TL-155 tradenames; and the fluoropolymers commercially available
from Dyneon LLC (Oakdale, Minn.) under the Dynamar FX 9613, Dynamar
FX 5920A, Dynamar FX 5911X, Dynamar FX 5912X, Dynamar PPA 790, and
Dynamar PPA 791 tradenames.
[0139] A specific example of an acrylic suitable for use as an
optional lubricant herein is the white powder acrylic commercially
available from the ATOFINA Chemicals Incorporation under the
Metablen L-1000SD tradename.
[0140] Method of Manufacture
[0141] The flushable tampon applicators of the present invention
may be prepared by any known or otherwise effective technique for
providing a disposable tampon applicator provided that the article
is made to contain water-dispersible and biodegradable materials
described herein, preferably a blend of water-dispersible and
biodegradable materials. Typically, the flushable tampon
applicators are molded in a desired shape or configuration using a
variety of molding techniques to provide a thermoplastic applicator
comprising an outer tubular member and a plunger. Such molding
techniques include injection molding, extrusion molding, blow
molding, compression molding, and cast film. These molding
techniques can be used alone or in combination to make the
flushable tampon applicators of the present invention. For example,
the outer tubular member and plunger components of the flushable
tampon applicators herein can be made using an injection molding
apparatus, or the outer tubular member and plunger can be made
using an extrusion molding apparatus, or the outer tubular member
can be made using injection molding and the plunger made using
extrusion molding, or the outer tubular member made by extrusion
molding and the plunger made by injection molding, or the outer
tubular member and/or plunger are made using a combination of
extrusion and injection molding.
[0142] Generally, the process of making flushable tampon
applicators of the present invention involves charging one or more
high molecular weight polyethylene oxides, one or more low
molecular weight polyethylene glycols, one or more
aliphatic/aromatic copolyesters, and any other ingredients such as
plasticizers and/or filler into an injection molding apparatus, and
molding the melt blended mixture comprising uniformly dispersed
filler into the desired flushable tampon applicator. Alternatively,
a blend of the thermoplastic materials, optional plasticizer, and
uniformly dispersed filler can be compounded into pellets by means
of an extruder, and the pellets are then constructed into flushable
tampon applicators using an injection molding apparatus.
[0143] One example of a procedure of making flushable tampon
applicators of the present invention involves mixing the
thermoplastic polymers, optional plasticizer, and filler in a
variable speed, high intensity blender, extruding the mixture at a
temperature above the melting temperature of the thermoplastic
polymers to form a rod, chopping the rod into pellets, and
injection molding the pellets into the desired flushable tampon
applicator form.
[0144] The extruders which are commonly used to melt process
thermoplastic compositions into compounded pellets are generally
single-screw extruders, twin-screw extruders, and kneader
extruders. Examples of commercially available extruders suitable
for use herein include the Black-Clawson single-screw extruders,
the Werner and Pfleiderer co-rotating twin-screw extruders, the
HAAKE Polylab System counter-rotating twin screw extruders, and the
Buss kneader extruders. A typical extrusion process can be
described as compounding blended components using a twin-screw
extruder having a screw diameter of 30 mm, a feed section, and a
die tip. The blend is compounded at about 100 revolutions per
minute (rpm) at a temperature ranging from about 60.degree. C. at
the feed section to about 130.degree. C. at the die tip. The final
product is a compounded rod that is chopped into pellets suitable
for molding into desired flushable tampon applicators using an
injection molding apparatus. General discussions of extrusion
molding are disclosed in the Encyclopedia of Polymer Science and
Engineering; Volume 6, pp. 571-631, 1986, and Volume 11, pp.
262-285, 1988; John Wiley and Sons, New York; which disclosures are
incorporated by reference herein.
[0145] Injection molding is the most commonly used process for
constructing and configuring tampon applicators into a desired
shape of form. This process is typically carried out under
controlled temperature, time, speed and pressure, and involves melt
processing pellets or blends of thermoplastic compositions wherein
the melted thermoplastic composition is injected into a mold,
cooled, and molded into a desired plastic object.
[0146] An example of a suitable injection molding machine is the
Engel Tiebarless ES 60 TL apparatus having a mold, a nozzle, and a
barrel that is divided into zones wherein each zone is equipped
with thermocouples and temperature-control units. The zones of the
injection molding machine can be described as front, center, and
rear zones whereby the pellets are introduced into the front zone
under controlled temperature. The temperature of the nozzle, mold,
and barrel components of the injection molding machine can vary
according to the melt processing temperature of the pellets and the
molds used, but will typically be in the following ranges:
15 Component Temp (.degree. C.) Nozzle 135-230 Front Zone 70-200
Center Zone 100-225 Rear Zone 120-225 Mold 20-50
[0147] Other typical processing conditions include an injection
pressure of from about 300 pounds per square inch (psi) to about
3000 psi (about 2 MPa to about 21MPa), a holding pressure of about
400 psi to about 2000 psi (about 3 Mpa to about 14MPa), a hold time
of about 2 seconds to about 25 seconds, and an injection speed of
from about 0.98 inches per second (in/sec) to about 8 in/sec.
[0148] Other suitable injection molding apparatus are the injection
molding machines made by Battenfeld, Brabender, Killion, Demag and
Arburg, Windsor, Hesas, Boy, Van Dorn, Engel, and the Fischer
companies. Specific examples of other suitable injection molding
machines include the Van Dom Model 150-RS-8F, the Battenfeld Model
1600, and the Engel Model ES80. A general discussion of injection
molding is disclosed in the Encyclopedia of Polymer Science and
Engineering, Volume 8, pp. 102-138, John Wiley and Sons, New York,
1987, which disclosure is incorporated by reference herein.
[0149] The flushable tampon applicators of the present invention
are generally made using the extrusion and injection molding
techniques described hereinabove. These techniques involve melt
processing the thermoplastic polymers, filler, and any optional
ingredients wherein the thermoplastic polymers, filler, and
optional ingredients have melting temperatures typically ranging
from about 25.degree. C. to about 350.degree. C., more typically
from about 40.degree. C. to about 300.degree. C., even more
typically from about 50.degree. C. to about 200.degree. C.
Therefore, the thermoplastic polymers suitable for use in making
the flushable tampon applicators of the present invention desirably
have individual melt flow rates of from about 0.1 gram/10 minutes
to about 600 grams/10 minutes, preferably from about 1 gram/10
minutes to about 400 grams/10 minutes, more preferably from about 5
grams/10 minutes to about 200 grams/10 minutes, even more
preferably from about 10 grams/10 minutes to about 150 grams/10
minutes, as determined according to the ASTM Test Method
D1238-E.
[0150] The final products of flushable tampon applicators of the
present invention are packaged in moisture-proof wrappers for
storage prior to use. The moisture-proof wrappers prevents moisture
from contacting the applicator or tampon pledget, and therefore
aids in the assurance of shelf-stabilily for the tampon and
provides an asethetically pleasing and acceptable tampon product
prior to actual use. The flushable tampon applicators of the
present invention can be packaged in any suitable wrapper provided
that the wrapper is soil proof and disposable with dry waste.
Preferred wrappers are those made from biodegradable materials
which create minimal or no environmental concerns for their
disposal. It is contemplated, however, that the tampon applicators
of the present invention can be packaged in flushable wrappers made
from paper, nonwoven, cellulose, thermoplastic, or any other
suitable flushable material, or combinations of these
materials.
EXAMPLES
[0151] The following examples further describe and demonstrate
embodiments within the scope of the present invention. The examples
are given solely for the purpose of illustration and are not to be
construed as limitations of the present invention, as many
variations thereof are possible without departing from the spirit
and scope of the invention. All exemplified concentrations are
weight-weight percents, unless otherwise specified.
Example 1
[0152] Flushable tampon applicators of the present invention are
made by a melt extrusion process of blending water-dispersible
polymers, biodegradable polymers, fillers, and any optional
ingredient using a Werner Pfleiderer ZSK-30 co-rotating twin screw
extruder having a screw diameter of 30 mm, six heating zones, a
four hole die plate, two feeding hoppers, and a liquid pump which
is connected to the extruder through a hole located between heating
zones 3 and 4. For example, powder ingredients are dry blended
together wherein the powder ingredients include water-dispersible
polymers such as high molecular weight polyethylene oxide
commercially available as POLYOX.RTM. WSR-80 and low molecular
weight polyethylene glycol commercially available as PEG-8000;
fillers such as calcium carbonate (commercially available as Vicron
15-15), talc (commercially available as ABT 2500), starch granule
materials (commercially available as Staley Pure Food Powdered
Starch and National Starch Melojel), and wood flours (commercially
available as Pine Wood Flour Grade 10020); and optional ingredients
such as ester wax (commercially available as Loxiol G33), magnesium
stearate, and Kemamide E. Likewise, ingredients in pellet form are
dry blended together such as a dry blend pellet mixture of
biodegradable polymers. Any ingredients added in liquid form are
mixed with other liquids prior to extrusion, for example, any
liquid plasticizes and any other liquid optional ingredient are
mixed together. Next, the powder dry blend mixture is fed into the
extruder through one feeding hopper while the pellet formed mixture
is fed into the extruder through the other feeding hopper. The
optional liquid mixture is pumped into the extruder through the
liquid pump. During the extrusion process, the water-dispersible
polymers, biodegradable polymers, optional plasticizers and any
other optional ingredient form a melt-blended mixture. The fillers
including inorganic and organic fillers are not melted and remain
in their particle forms during the extrusion process and, therefore
are uniformly dispersed throughout the melt blend mixture. Then,
the melt blend mixture containing uniformly dispersed filler
particles is extruded to the end of the extruder to the die to form
four rods. The rods are carried on a conveyor, air cooled, and
pelletized using a pelletizer for injection molding into a desired
flushable tampon applicator. Compositions for forming flushable
tampon applicators of the present invention and extrusion settings
are further described hereinbelow in Table 5 and Table 6.
16TABLE 5 Extrusion Molded Thermoplastic Compositions Zone 1 Zone 2
Zone 3 Zone 4 Zone 5 Zone 6 Die Screw Speed Composition (.degree.
C.) (.degree. C.) (.degree. C.) (.degree. C.) (.degree. C.)
(.degree. C.) (.degree. C.) (rpm) PEO.sup.1/PEG.sup.2/BAK 404.sup.3
Off 80 101 128 141 114 120 100 (40/30/30 blend)
PEO.sup.1/PEG.sup.2/BAK 404.sup.3 60 70 110 118 122 103 105 250
(40/40/20 blend) PEO.sup.1/PEG.sup.2/Eastar 14776.sup.4 Off 80 99
130 140 115 120 100 (40/30/30 blend) PEO.sup.1/PEG.sup.2/Bionolle
3001.sup.5 60 70 110 113 122 109 103 300 (66/17/17 blend)
PEO.sup.1/PEG.sup.2/Bionolle 3001.sup.5 Off 50 125 130 145 125 116
100 (40/30/30 blend) PEO.sup.1/PEG.sup.2/Biomer 209H.sup.6 75 85 98
146 161 148 130 300 (40/30/30 blend) PEO.sup.1/PEG.sup.2/BAK
404.sup.3/ Off 80 101 128 141 114 120 100 P-645.sup.7 (36/27/27/10
blend) PEO.sup.1/PEG.sup.2/BAK 404.sup.3/ Off 80 101 128 141 114
120 100 P-4141.sup.8 (36/27/27/10 blend)
PEO.sup.1/PEG.sup.2/Eastar- .sup.4/ 75 80 96 148 164 113 91 275
P-645.sup.7/CaCO.sub.3.sup.10 (11/9/20/10/50 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 100 125 145 89 90 275
P-645.sup.7/CaCO.sub.3.sup.10 (24/18/18/10/30 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 100 125 145 100 95 275
P-645.sup.7/CaCO.sub.3.sup.10 (29/21/10/10/30 blend)
PEG.sup.2/PEG.sup.11/Eastar.sup.4/ 75 80 99 121 144 106 84 275
P-645.sup.7/CaCO.sub.3.sup.10 (20/5/40/5/30 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 100 125 144 100 93 275
P-645.sup.7/CaCO.sub.3.sup.10 (16/12/12/10/50 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 99 148 162 50 90 300
P-645.sup.7/Talc.sup.12 (17/13/10/10/50 blend) rpm --revolutions
per minute .sup.1polyethylene oxide available as POLYOX .RTM.
WSR-80 from the Union Carbide Corporation .sup.2polyethylene glycol
available as PEG-8000 from Union Carbide .sup.3aliphatic
polyesteramide available as BAK 404 from Bayer Aktiengesellschaft
.sup.4aliphatic-aromatic copolyester available as Eastar
Biodegradable Copolyester 14776 from Eastman Chemical
.sup.5diacid-diol aliphatic polyester available as BIONOLLE 3001
from the Showa Highpolymer Company, Ltd. .sup.6polyhydroxyalkanoate
available as Biomer 209H from Biomer Frost-Kasten-Str., Krailling,
Germany .sup.7adipate polyester plasticizer available as Plasthall
645 from C. P. Hall .sup.8triethylene glycol caprate-caprylate
plasticizer available as Plasthall 4141 from C. P. Hall
.sup.10calcium carbonate available as Vicron 15-15 from Specialty
Mineral .sup.11polyethylene glycol available as PEG-600 from Union
Carbide .sup.12talc available as ABT 2500 from Specialty
Mineral
[0153]
17TABLE 6 Extrusion Molded Thermoplastic Compositions Zone 1 Zone 2
Zone 3 Zone 4 Zone 5 Zone 6 Die Screw Speed Composition (.degree.
C.) (.degree. C.) (.degree. C.) (.degree. C.) (.degree. C.)
(.degree. C.) (.degree. C.) (rpm)
PEG.sup.2/PEG.sup.11/Eastar.sup.4/ 75 80 99 121 144 106 84 275
P-645.sup.7/CaCO3.sup.10 (20/5/40/5/30 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 100 125 144 100 93 275
P-645.sup.7/CaCO3.sup.10 (16/12/12/10/50 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 99 148 162 50 90 300
P-645.sup.7/Talc.sup.12 (17/13/10/10/50 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 75 80 100 125 145 90 91 275
P-645.sup.7/Talc.sup.12 (24/18/18/10/30 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/AB.sup.13/ 70 70 90 115 135 135 95
60 wood flour.sup.14/TiO.sub.2.sup.15/ Kemamide E.sup.16
(17/17/25/5/30/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 70 75
90 115 135 110 100 150 Starch.sup.17/P-645.sup.7/Kemamide E.sup.16
(18/13/13/50/5/1 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 50 70 102
122 134 110 92 260 Starch.sup.18/P-645.sup.7/Kemamide
E.sup.16/MgSt.sup.19 (15/10/37/30/5/1/2 blend)
PEO.sup.1/Eastar.sup.4CaCO.sub.3.sup.10/ 50 70 115 137 153 91 114
250 P-645.sup.7 (18/15/65/4 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4- / 50 70 121 124 140 105 95 250
CaCO.sub.3.sup.10/P-645.sup.7/Kemami- de E.sup.16 (15/10/29/40/5/1
blend) PEO.sup.1/PEG.sup.2/East- ar.sup.4/ 50 70 110 133 137 115
105 250 CaCO.sub.3.sup.10/P-645.sup- .7/MgSt.sup.19/ Loxiol
G33.sup.20 (15/10/26/40/5/2/2 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 50 70 120 125 140 105 95 250
CaCO.sub.3.sup.10/P-645.sup.7/Kemamide E.sup.16 (15/10/39/30/5/1
blend) PEO.sup.1/Eastar.sup.4/CaCO.sub.3.sup.10/ 50 70 120 133 138
107 99 250 P-645.sup.7/Kemamide E.sup.16 (25/39/30/5/1 blend)
PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 50 70 115 128 141 112 95 250
CaCO.sub.3.sup.10/P-645.sup.7/Kemamide E.sup.16/Paraffin wax.sup.21
(15/10/34/30/5/1/5 blend)
PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/Mg 70 85 110 133 140 123
106 250 St.sup.19 (17.5/64/17.5/1 blend)
PEG.sup.2/Eastar.sup.4/CaC- O.sub.3.sup.10/ 70 85 110 135 157 118
114 252 MgSt.sup.19/P-643.sup.22/ DC4-7051.sup.25 (15/62/15/1/5/2
blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 50 70 110 134 139 121 105
250 CaCO.sub.3.sup.10/P-645.sup.7/MgSt.sup.19/ DC9506.sup.23
(15/10/26/40/5/2/2 blend) PEO.sup.1/PEG.sup.2/Eastar.sup.4/ 50 70
110 133 138 117 102 250 CaCO.sub.3.sup.10/P-645.sup.7/MgSt.sup.19/
Loxiol G33.sup.20/Kraton G 1652.sup.24 (14.5/9.5/25.5/39.5/5/2/2/2
blend) .sup.13AB anti-block processing aid available from Eastman
Chemical .sup.14pine wood flour available as Pine Wood Flour Grade
10020 from American Wood Fibers .sup.15titanium dioxide available
from DuPont White Pigment & Mineral Products .sup.16euracamide
available as Kemamide E Ultra from Crompton Corpration .sup.17Food
grade corn starch available as Staley Pure Food Powdered from A. E.
Staley Manufacturing Co. .sup.18Food grade corn starch available as
National Starch Melojel from National Starch & Chemical
.sup.19Magnesium Stearate available from Aldrich Chemical Company
.sup.20ester wax of fatty acid and fatty alcohol available as
Loxiol 033 from Cognis Plastics Technology .sup.21paraffinic
hydrocarbon wax available as Paraflint H-1 from Moore & Munger
Inc .sup.22adipate polyester plasticizer available as Plasthall 643
from C. P. Hall .sup.23silicone elastomer powder available as DC
9506 from Dow Corning .sup.24SEBS, tri-block copolymer of styrene
and ethylene-butylene with poly(ethylene-butylene) in the center
available as Kraton G 1652 from Kraton Polymers .sup.25silicone
resin modifier available as DC4-7051 from Dow Corning
Example 2
[0154] Flushable tampon applicators of the present invention are
made by dry blending a mixture of water-dispersible and
biodegradable polymers, and then feeding this dry blended mixture
of polymers into a HAAKE Polylab System counter-rotating twin screw
extruder. The extruder is equipped with a single hole die plate for
compounding the dry blended mixture into a single strand of molten
plastic that is air-cooled and then chopped into small discs having
a diameter of 20 mm and a thickness of 0.5 mm. The small discs are
grounded using an IMS LP-288SC Grinder for injection molding into a
desired flushable tampon applicator. The dry blended thermoplastic
compositions of water-dispersible polymers and biodegradable
polymers, in addition to the extrusion apparatus settings, are
described hereinbelow in Table 7.
18TABLE 7 Extrusion Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/PLA 44D.sup.9 PEO.sup.1/PEG.sup.2/PLA
62-50D.sup.9 Extruder Settings (40/30/30 blend) (40/30/30 blend)
Zone 1 (.degree. C.) 80 80 Zone 2 (.degree. C.) 200 200 Zone 3
(.degree. C.) 210 210 Die (.degree. C.) 130 120 Screw Speed 30 25
(rpm) .sup.9polylactic acids available as PLA 44D grade and PLA
62-50D grade from Cargill-Dow Polymers, LLC
[0155] Injection Molding
[0156] An Engel Tiebarless ES 60 TL injection molding machine is
suitable for manufacturing the final product of thermoplastic
pellets of Examples 1 and 2 into flushable tampon applicators of
the present invention. The injection molding process involves using
a 25 mm screw and controlled processing conditions of controlled
temperature, time, speed, and pressure, wherein the pellets are
melt processed, injected into a mold, cooled, and then molded into
the desired flushable tampon applicator.
[0157] The Engel injection molding machine is also suitable for
manufacturing composite paper flushable tampon applicators.
Typically, spiral-wound paper is formed into paper tubes having a
length of about 35 mm, inside diameter of about 10.8 mm, outside
diameter of about 11.2 mm, and a weight of about 0.25 grams. The
paper tube is positioned over a mold core pin, the mold is clamped
shut, and a thermoplastic composition is injected into the mold.
The paper tube is positioned over the mold core pin such that the
thermoplastic composition is melt processed to flow over the entire
length of the outer surface of the paper tube. Therefore, the
resultant composite paper tampon applicator comprises a paper inner
surface, thermoplastic resin outer surface, and thermoplastic
petals and grip components.
[0158] Examples of thermoplastic compositions and injection molding
settings are described hereinbelow in Table 8 through Table 15.
19TABLE 8 Injection Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/
PEO/PEG/ Injection Molding BAK 404.sup.3 BAK 404.sup.3 Eastar
14776.sup.4 Bionolle 3001.sup.5 Settings (40/30/30 blend) (40/40/20
blend) (40/30/30 blend) (66/17/17 blend) Nozzle (.degree. C.) 177
163 149 135 Zone 1 (.degree. C.) 149 107 127 74 Zone 2 (.degree.
C.) 160 135 138 107 Zone 3 (.degree. C.) 168 149 143 121 Mold
(.degree. C.) 21 21 21 21 Screw Speed (rpm) 120 192 120 192
Injection Speed (in/sec) 4 4 4 4 Injection Pressure (psi) 843 418
1562 1302 Hold Time (sec) 4 12 8 5 Hold Pressure (psi) 500 800 650
1250 Cool Time (sec) 30 30 25 30 psi--pounds per square inch
in/sec--inches per second sec--seconds
[0159]
20TABLE 9 Injection Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/
PEO.sup.1/PEG.sup.2/ BAK 404.sup.3/P-645.sup.7 BAK
404.sup.3/P-4141.sup.8 Injection Molding Bionolle 3001.sup.5 Biomer
209H.sup.6 (36/27/27/10 (36/27/27/10 Settings (40/30/30 blend)
(40/30/30 blend) blend) blend) Nozzle (.degree. C.) 221 149 149 149
Zone 1 (.degree. C.) 193 65 65 65 Zone 2 (.degree. C.) 216 79 79 79
Zone 3 (.degree. C.) 216 143 121 121 Mold (.degree. C.) 21 21 21 21
Screw Speed (rpm) 120 192 192 192 Injection Speed (in/sec) 4 4 4 4
Injection Pressure (psi) 641 388 405 564 Hold Time (sec) 4 15 8 8
Hold Pressure (psi) 1100 500 500 500 Cool Time (sec) 35 60 40
40
[0160]
21TABLE 10 Injection Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/ PLA 44D.sup.9 PLA
62-50D.sup.9 Composite Paper Injection Molding (40/30/30 (40/30/30
with 40/30/30 blend of Settings blend) blend)
PEO.sup.1/PEG.sup.2/BAK 404.sup.3 Nozzle (.degree. C.) 199 199 163
Zone 1 (.degree. C.) 149 149 121 Zone 2 (.degree. C.) 149 149 140
Zone 3 (.degree. C.) 177 177 152 Mold (.degree. C.) 32 32 24 Screw
Speed 120 120 160 (rpm) Injection Speed 4 4 3 (in/sec) Injection
Pressure 348 315 400 (psi) Hold Time (sec) 5 5 5 Hold Pressure 800
800 300 (psi) Cool Time (sec) 30 30 4
[0161]
22TABLE 11 Injection Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/
PEG.sup.2/PEG.sup.11/ Eastar.sup.4/P-645.sup.7/
Eastar.sup.4/P-645.sup.7/ Eastar.sup.4/P-645.sup.7/
Eastar.sup.4/P-645.sup.7/ CaCO.sub.3.sup.10 CaCO.sub.3.sup.10
CaCO.sub.3.sup.10 CaCO.sub.3.sup.10 Injection Molding
(11/9/20/10/50 (24/18/18/10/30 (29/21/10/10/30 (20/5/40/5/30
Settings blend) blend) blend) blend) Nozzle (.degree. C.) 163 163
163 163 Zone 1 (.degree. C.) 121 121 121 121 Zone 2 (.degree. C.)
135 135 135 135 Zone 3 (.degree. C.) 149 149 149 149 Mold (.degree.
C.) 24 24 24 24 Screw Speed (rpm) 192 192 192 192 Injection Speed
(in/sec) 4 4 4 4 Injection Pressure (psi) 700 510 576 410 Hold Time
(sec) 7.5 5 5 7.5 Hold Pressure (psi) 500 500 500 500 Cool Time
(sec) 45 45 45 45
[0162]
23TABLE 12 Injection Molded Thermoplastic Compositions
PEG.sup.2/PEG.sup.11/ PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/
PEO.sup.1/PEG.sup.2/ Eastar.sup.4/AB.sup.13/wood
Eastar.sup.4/P-645.sup.7 Eastar.sup.4/P-645.sup.7/
Eastar.sup.4/P-645.sup.7/ flour.sup.14/TiO.sub.2.sup.15/
CaCO.sub.3.sup.10 Talc.sup.12 Talc.sup.12 Kemamide E.sup.16
Injection Molding (16/12/12/10/50 17/13/10/10/50 24/18/18/10/30
17/17/25/5/30/5/1 Settings blend) blend) blend) blend) Nozzle
(.degree. C.) 163 163 163 174 Zone 1 (.degree. C.) 121 121 121 149
Zone 2 (.degree. C.) 135 135 135 168 Zone 3 (.degree. C.) 149 149
149 171 Mold (.degree. C.) 21 24 24 38 Screw Speed (rpm) 192 192
192 192 Injection Speed (in/sec) 4 4 4 2 Injection Pressure (psi)
744 410 451 1750 Hold Time (sec) 10 7.5 5 20 Hold Pressure (psi)
750 500 500 750 Cool Time (sec) 30 45 45 70
[0163]
24TABLE 13 Injection Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/ PEO.sup.1/PEG.sup.2/ PEG.sup.2/PEG.sup.11/
Eastar.sup.4/Starch.sup.17/ PEO.sup.1/Eastar.sup.4/
Eastar.sup.4/CaCO.sub.3.sup.10/ Eastar.sup.4/CaCO.sub.3.sup.10/
P-645.sup.7/ CaCO.sub.3.sup.10/ P-465.sup.7/ P-645.sup.7/ Kemamide
E.sup.16 P-645.sup.7 Kemamide E.sup.16 Kemamide E.sup.16 Injection
Molding (18/13/13/50/5/1 (18/15/65/4 (15/10/29/40/5/1
(15/10/39/30/5/1 Settings blend) blend) blend blend) Nozzle
(.degree. C.) 149 171 135 182 Zone 1 (.degree. C.) 93 104 93 104
Zone 2 (.degree. C.) 121 160 121 171 Zone 3 (.degree. C.) 141 166
127 177 Mold (.degree. C.) 22 19 21 24 Screw Speed (rpm) 192 240
240 360 Injection Speed (in/sec) 2 3 3 3 Injection Pressure (psi)
1880 2820 625 1530 Hold Time (sec) 20 15 5 15 Hold Pressure (psi)
750 2000 500 1000 Cool Time (sec) 60 40 30 30
[0164]
25TABLE 14 Injection Molded Thermoplastic Compositions
PEO.sup.1/PEG.sup.2/ PEO.sup.1/Eastar.sup.4
Eastar.sup.4/CaCO.sub.3.sup.10/ CaCO.sub.3.sup.10/ P-645.sup.7/
PEG.sup.2/Eastar.sup.4/ P-645.sup.7/ Kemamide E.sup.16/
CaCO.sub.3.sup.10/ Injection Kemamide E.sup.16 Paraffin wax.sup.21
MgSt.sup.19 Molding (25/39/30/5/1 (15/10/34/30/5/1/5
(17.5/64/17.5/1 Settings blend) blend) blend) Nozzle (.degree. C.)
135 135 163 Zone 1 (.degree. C.) 93 93 82 Zone 2 (.degree. C.) 121
121 121 Zone 3 (.degree. C.) 127 127 143 Mold (.degree. C.) 24 18
18 Screw Speed 240 360 360 (rpm) Injection Speed 3 4 5 (in/sec)
Injection Pressure 898 566 640 (psi) Hold Time (sec) 15 10 10 Hold
Pressure 1500 500 1000 (psi) Cool Time (sec) 20 20 35
[0165]
26TABLE 15 Injection Molded Thermoplastic Compositions
PEG.sup.2/Eastar.sup.4/
PEO.sup.1/PEG.sup.2/Eastar.sup.4/CaCO.sub.3.sup.10/
CaCO.sub.3.sup.10/MgSt.sup.19/ P-645.sup.7/MgSt.sup.19/Loxiol
G33.sup.20/ Injection P-643.sup.22/DC4-7051.sup.25 Kraton G
1652.sup.24 Molding (15/62/15/1/5/2 (14.5/9.5/25.5/39.5/5/2/2/2
Settings blend) blend) Nozzle (.degree. C.) 163 163 Zone 1
(.degree. C.) 82 99 Zone 2 (.degree. C.) 121 143 Zone 3 (.degree.
C.) 143 157 Mold (.degree. C.) 18 18 Screw Speed 360 360 (rpm)
Injection Speed 5 5 (in/sec) Injection Pressure 567 714 (psi) Hold
Time (sec) 10 5 Hold Pressure 1000 500 (psi) Cool Time (sec) 35
45
* * * * *