Note: Descriptions are shown in the official language in which they were submitted.
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CODISPENSING OF PHYSICALLY SEGREGATED DEI~TIFRIC~S AT CONSISTANT RATIOS
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BACKGROUND OF THE rNVENTION
1. Field of the Invention
The present invention is directed to a p~CI~ging system for storing and
simultaneously dispensing physically separated components of a multicomponent
dentifrice at constant predetermined ingredient ratios in a multilayer unmixed relationship.
2. Prior Art
Multicomponent dentifrice compositions are known to the art wherein the
individual components cont~ining reactive ingredients are physically segregated during
storage and are simultaneously dispensed as viscous paste or liquid materials which
interact when mixed with each other, as during brushing, the components being dispensed
at specific predetermined ingredient ratios for optimum efficacy and performance.
For example, it has long been known to include fluoride releasing compounds in
dentifrices as anticaries agents, and it has been established that these compounds are
effective to reduce the incidence of dental caries. The effectiveness of the dispensed
fluoride is dependent upon the amount of fluoride ion which is available for deposition on
the dental tissue being treated. It is, therefore, desirable to formulate dentifrice
compositions which provide maximum fluoride ion availability in brushing solutions
formed using the dentifrice.
One effective way of depositing fluoride on teeth is to use a two-component
dentifrice composition comprised of a calcium cont~ining component and the other a
fluoride containing component to precipitate calcium fluoride on teeth.
For example, US 5,045,305 teaches a two component dentifrice for fluoridating
teeth in which one component contains CaC12 and the other contains fluoride ions in the
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form of NaF, the separate components being admixed immediately prior to introduction in
the mouth to effect precipitation of CaF2
US. Patent No. 5,145,668 discloses a method of fluoridating teeth wherein there is
mixed during toothbrushing a first component comprising a soluble calcium salt such as
CaC12 and a second component cont~ining a hydrolyzable complex fluoride compoundsuch as sodium fluorosilicate (Na2SiF6) the mixing of the components resulting in
hydrolysis of the complex fluoride compound and precipitation of calcium fluoride and its
deposition on tooth surfaces.
US 5,476,647 discloses a two-component fluoride deposition system wherein the
first component of the system contains a soluble calcium source and a soluble Ca-
complexing anion such as ethylene diaminetetraacetic acid, the calcium being partially
bound to the Ca-complex agent. The second component contains a fluoride salt such as
l ~ sodium fluoride or stannous fluoride. When the two components are combined,
precipitation of calcium fluoride (CaF2) removes free Ca2+ from the solution releasing of
additional free Ca2+ from the calcium complexing agent, which, in turn, causes additional
CaF2 to precipitate.
In copending U.S. patent application Serial No. filed
1996 there is disclosed a dentifrice for fluoridating teeth utili7ing
two separate physically segregated semi-solid dentifrice components which contain
fluoride salt and calcium ion containing abrasive ingredients which are reactive when
mixed together upon application to teeth, the first component being an aqueous, semi-
solid dentifrice composition co~ g a fluoride ion releasing salt such as an alkali metal
salt such as sodium fluoride in a vehicle in which the ingredients thereof are non-reactive
with the fluoride salt, and the second component is comprised of a vehicle cont~ining a
calcium ion containing abrasive such as hydrated dicalcium phosphate wherein theindividual dentifrice components are substantially rheologically equivalent and are
simultaneously extruded from a dual compartmented container. When the ingredients in
the dispensed components are at the proper reactant ratio maximum fluoride availability is
provided as precipitated calcium fluoride upon mixing of the dentifrice components during
application to the teeth as by brushing.
3 5 The most convenient and least cost way to dispense physically separated
components of multi-component dentifrices is from a collapsible, compartmented plastic
tube. Dual compartmented collapsible tubes for the simultaneous coextrusion of two
.. . .. .
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physically separated dentifrice components are known to the art whereby compression of
the tube, as by squeezing, dispenses a single banded multilayer ribbon product. The
bodies of these dual compartmented tubes are typically sealed at one end and arem~nllf~ctured from plastic sheet. The structure of the dual compartmented tube further
includes a partition within the tube body for defining separate compartments therein and a
relatively rigid neck portion is provided at the unsealed end having a discharge opening
extending therethrough, the outer peripheral surface of the neck portion being threaded or
otherwise constructed to enable a cap to be threaded or otherwise attached thereon to seal
the tube. Examples of such dual compartmented tube structures for dispensing
multicomponent dentifrices are disclosed in U.S. Patents 4,481,757 and 4,687,663.
U.S. 4,487,757 discloses a dual compartmented collapsible tube separated into
two compartments by a partition which extends to the dispensing nozzle which physically
segregates and dispenses a dual component toothpaste containing reactive ingredients,
wherein one component contains an alkali metal bicarbonate salt (e.g., NaHCO3) and the
other contains an acid or acid salt (e.g., citric acid) which is reactive with the bicarbonate
salt to produce effervescence (carbon dioxide) upon .simlllt~neous dispensing of unmixed
layers of both components and intimate mixing thereof during toothbrushing.
U.S. 4,687,663 discloses a dual compartmented tube in which the dual component
dentifrice dispensed is composed of a first hydrogen peroxide containing gel and a sodium
bicarbonate containing second component. The tube is separated into two compartments
by a partition extending into the dispensing nozzle.
A disadvantage experienced by the prior art with two component dispensing
systems such as are disclosed in the above discussed patents is that efforts to utilize such
systems using semi-solid, extrudable oral care products such as toothpastes and gels
containing reactive ingredients which require constant predetermined ingredient ratios to
achieve optimum performance is that unequal dispensing of the dentifrice components
from plastic compartmented tubes occurs so that optimum interaction of the reacted
ingredients when the two components are mixed during brushing of the teeth, is not
achieved. For example, U.S. 5,137,178 discloses (col. 1, lines 29-39) that a common
problem of the known art in dispensing dual component reactive products is the inability
.to control.the relative flow of each component from its respective compartment in a dual
3 5 compartmented container, there being a particular problem in extruding equal volumes of
the two components. U.S. 5,020,694 (col. 1, line 64 to col. 3, line 3) discloses that the
dual compartmented tubes ofthe prior art as represented by previously discussed U.S.
... . . .
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4,487,757 and U.S. 4,687,663 suffer from the disadvantage that the tubes tend to dispense
dual component dentifrice materials in uncontrolled, varying proportions even though the
rheologies of the components are similar.
Unequal dispensing of the components of a multi-component dentifrice causes a
variation in the component layers in the multilayer dentifrice portion which is next
dispensed, so that a3though the components which are next dispensed are dispensed
synchronously, the ingredients in the dispensed components are not matched at the correct
reactant ratios for optimum interaction of the reactive ingredients. ln the case of
multicomponent dentifrices of the type disclosed in S.N. used for the
fluoridation of teeth, maximum fluoride availability as precipitated calcium fluoride is not
achieved when the unequally dispensed components are mixed during brushing.
U.S. Patents 5,020,694 and U.S. 5,038,963 describe rigid piston type
multicompartmented dispensing containers for simultaneous coextrusion of two or more
dentifrice components in a predetermined proportion. These rigid containers have the
advantage of control over the coextrusion process. However a considerable amount of
plastic material is involved in their construction. For environmental and cost reasons,
packaging with less plastic material is commercially desirable. Therefore, there is a need
in the art for a non-rigid plastic compartmented container or tube for storing and
simultaneously dispensing physically separated dentifrice components containing reactive
ingredients at constant predetermined ingredient ratios whereby optimum interaction
between reactive ingredients is obtained, such container requiring considerably less plastic
material for its manufacture.
2~
SUMMARY OF THE INVENTION
ln accordance with the present invention there is provided a means for the
constant codispensing in predetermined proportions of physically separated dentifrice
components containing different reactive ingredients from a multicompartmented, non-
rigid, container having collapsible sidewalls, the container including (1) a collapsible body
portion formed from a plastic web material which deforms under a deflective force of
about 1.0 pound or greater applied thereto and (2) a moveable partition within the
~ontainer body defining separate compartments, the partition being a membrane which has
a thickness less than that of the body sidewalls which deforms under a deflective force of
less than 0.5 pounds and is displaced in response to a pressure di~enlial developed
thereacross upon compression of the container sidewalls, the displacement of the
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membrane substantially vitiating the pressure di~èl ell~ial and equalizing the compressive
forces exerted on the dentifrice components housed in the container compartments,
whereby substantially constant codispensing of the components in predetermined
proportions is attained when the components are formulated such that the compression
forces required to extrude the individual dentifrice components are substantially
equivalent.
DESCRIll'TION OF T~ PREFER~ED EMBODIMENTS
The Dentifrice Components
The term "substantially equivalent Compressive Force" as used herein means that
the individual components of the multicomponent dentifrice of the present invention are
formulated so that the force required to actuate the flow and extrusion of an individually
i 5 housed dentifrice component from the container outlet does not differ by more than 20%
from any other separately housed component so that correctly proportioned interaction
between the dirrer~nl reactive ingredients of the components is achieved when the
components are ultimately mixed together.
It has been determined that individual dentifrice components when they contain
different reactive ingredients encounter di~e~ ~n~ surface forces with respect to the plastic
sidewalls of the collapsible, non-rigid container in which they are housed as they are
extruded from the container compartments and therefore to provide for ~imlllt~neous
coextrusion of the individual components wherein the reactive ingredients contained
therein are in a predetermined proportion, the vehicles used to prepare the individual
dentifrice components must be adjusted to account for the different surface forces
encountered by the dentifrice components being extruded so that the compressive force
necessary for controlled coextrusion is substantially equivalent.
It has been further determined that substantially constant codispensing of dentifrice
components cont~ining different reactive ingredients is achievable with the codispensing
system of the present invention when the individual dentifrice components are formulated
to be extrudable under a Compressive Force of about 0.5 to about 20 pounds and
--preferably about I to about 10 pounds.
The term "Compressive Force" measured in pounds (Ibs), as used herein, and in
the appended claims, means the force required to extrude 1-2 grams of a dentifrice
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component housed in a stainless steel container, a distance of 5 millimeters (mm) through
an aperture opening of 3.8mm diameter at a temperature of 23~C at a fixed rate of 150
millimeters/minute (mm/min). To measure such a compressive force, the dentifricecomponent is placed in a stainless steel container having a 2.0 centimeter (cm) inside
S diameter. The bottom of the stainless steel container is equipped with an orifice which is
20mm in length and has an inside orifice diameter of 0.38cm. A friction1ess teflon piston
with an outside diameter which is equal to the inside diameter of the stainless steel
container is placed on top of the dentifrice. An Instron~ compression tester is operated
to measure the force required to move the teflon piston down a Smm distance at 150
mm/min. The Compressive Force required for extrusion is obtained at the inflection point
(change in slope) in a force vs. distance curve; the force applied by the piston causing the
dentifrice component to flow increasing linearly until there is a change in the slope
indicating the initiation of dentifrice component extrusion. To obtain equal dispensing of
the separately housed dentifrice components it is critical to the practice of the present
invention, that the compression force measured at the inflection point for each component
be within + 20% of the other.
The compressive force required to effect extrusion of the dentifrice components of
the present invention may be adjusted by the selection and concentration of the ingredients
of the dentifrice vehicle in which the reactive ingredients are incorporated.
The dentifrice vehicle used in the practice of the invention is adjusted to impart to
the dentifrice component the pasty consistency, body and non-tacky nature which is
characteristic of conventional toothpastes or gels. The vehicle is non-reactive with the
reactive ingredients of the dentifrice and includes water, a suitable humectant such as
glycerin, sorbitol, propylene glycol, polyethylene glycol, or any suitable mixture thereof
and a thickening agent.
The humectant typically comprises about 10 to about 70% by weight of the
dentifrice component and preferably about 20 to about 50% by weight of the dentifrice
component Water may be included in the vehicle at a concentration of about 6 to about
70% by weight of the component and preferably about 15 to about 40% by weight.
Thickening agents incorporated in the dentifrice components of the present
3 5 invention include natural and synthetic gums and colloids examples of which include iota
carrageenan, kappa carrageenan, lamda carrageenan and mixtures thereof, xanthan gum,
carboxymethyl cellulose, sodium carboxymethyl cellulose, starch, polyvinylpyrrolidone,
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hydroxyethylpropylcellulose, hydroxybutyl methyl cellulose, hydroxypropyl methylcellulose, hydroxyethyl cellulose, laponites and magnesium aluminum silicates. Preferred
thickening agents are thickeners which impart elastic structure to the dentifrice
components so that progressive, variable thickening of the dentifrice component on
storage is avoided. When such thickeners are used in the preparation of the dentifrice
- components used in the practice of the present invention the compressive force required
for extrusion of the dentifrice component does not substantially change during storage.
Examples of thickeners which impart elastic structure include the different types of
carrageenan, laponites, magnesium all]min-lm silicates available commercially under the
tradename Veegum and polyoxyethylene-polyoxypropylene block copolymers availableunder the trademark "Pluronic".
A thickener which imparts the desired elastic structure to dentifrice componentswhich is most is preferred in the practice of the present invention is a cellulose gel formed
from a dried, spray dried or bulk dried, co-processed, mixture of a microcrystalline
cellulose and a cellulose gum such as carboxymethylcellulose, xanthan gum or sodium
alginate. An example of such cellulose gels are those sold by the FMC Corporation under
the tradename Avicel which generally contain about 80 to about 90% by weight
microcrystalline cellulose and about 10 to about 20% by weight cellulose gum. The
particle size range of the gel is from submicron, that is, less than 0.2 micron to about 100
microns, and preferably about 0.2 to about 20 microns. A cellulose gel particularly
preferred for use in the practice ofthe present invention is Avicel RC-591-F which is a
spray dried cellullose gel having the following composition and properties:
% Microcrystalline Cellulose 88
% Colloidal (0.2 micron) 70
% Carboxymethyl cellulose 12
Initial Viscosity* 39-175 at 1.2%
Set Up Viscosity** 1250 cps at 1.2%
* Initial Viscosity: 120 secs. using a BrookfieldO RVT Viscometer #l spindle at
20 rpms (revolutions per minute).
** Set-up Viscosity: 24 hours using a Brookfield~) RVT
Vi.ccomPtcr #3 spindle at 20 rpms.
Thickening agents such as Avicel RC-S91-F may be incorporated in the dentifrice
components of the present invention at a concentration of about 0.05 to about 2% by
weight and preferably about 0.1 to about 1.5% by weight.
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Surfactants are used in the preparation of dentifrice components of the present
invention to aid in the thorough dispersion of the dentifrice components throughout the
oral cavity when applied thereto as well as to improve the cosmetic acceptability and
detersive and foaming properties of the combined components. The surfactant is included
in the dentifrice vehicle of the individual components of the present invention at a
concentration of about 0.5 to about 3.0% by weight and preferably about 1.0 to about
2.0% by weight.
Among the surfactants useful in the practice of the present invention are salts of
the higher alkyl sulfates, such as sodium lauryl sulfate or other suitable alkyl sulfate having
8 to 18 carbon atoms in the alkyl group; sodium lauryl sulfoacetate, salts of sulfonated
monoglycerides of higher fatty acids, such as sodium coconut monoglyceride sulfonate or
other suitable sulfonated monoglycerides of a fatty acids of 10 to 18 carbon atoms; salts of
amides of higher fatty acid, e.g., 12 to 16 carbon atom acids, with lower aliphatic amino
acids, such as sodium-N-methyl-N-palmitoyl tauride, sodium N-lauroyl-, N-myristoyl- and
N-palmitoyl sarcosinates; salts of the esters of such fatty acids with isotonic acid or with
glycerol monosulfate, such as the sodium salt of monosulfated monoglyceride of
hydrogenated coconut oil fatty acids; salts of olefin sulfonates, e.g. alkene sulfonates or
alkene sulfonates or mixtures thereof having 12 to 16 carbon atoms in the carbon chain of
the molecule; and soaps of higher fatty acids, such as those of 12 to 18 carbon atoms, e.g.,
coconut fatty acids. The cation of the salt may be sodium, potassium or mono-. di or
triethanol amine.
The practice of the present invention applies generally to dentifrice componentswhich must be physically segregated from the other when each individually contains an
ingredient reactive with the other. For example, peroxide compounds are very reactive
ingredients and need to be separated from many dentifrice ingredients such as flavor
compounds, vitamins (A, C, E), antibacterial agents such as triclosan, and polyphosphates
such as sodium tripolyphosphate. Cationic compounds such like stannous ion,
chlorhexidine digluconate, and cetyl pyridinium chloride also must be separated from
anionic components of dentifrices such as tartar control agents (sodium tripolyphosphate),
calcium and silica abrasives, and the like.
.
3 5 By way of more specific example, when it is desired to fluoridate teeth by
precipitation of calcium fluoride, the first component of the dual component dentifrice
composition contains a water soluble, fluoride releasable salt such as an alkali metal
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fluoride such as NaF, KF, sodium monofluorophosphate or SnF2. The preferred fluoride
salt for the purposes of the present invention is NaF. The fluoride salt is incorporated hl
the first component of the dentifrice composition at a concentration of about 0.1 to about
1% by weight, and preferably at about 0.25 to about 0.5% by weight. At these preferred
concentrations, about 750 ppm to about 1500 ppm, fluoride ion will be available to teeth
when the combined first and second components of the dentifrice composition are
admixed when applied to the teeth.
Other specific examples of reactive ingredients which may be incorporated in thefirst dentifrice component include peroxide compounds such as hydro~en peroxide and
calcium peroxide or organic acidic ingredients such as citric acid or salts thereof which
may be included in the first dentifrice component at a concentration of about 0. 5 to about
5% by weight of the component.
The second component of the dentifrice composition of the present invention
includes a reactive polishing or abrasive ingredient such as dicalcium phosphate or an
alkali metal bicarbonate salt. When the second component of the dentifrice composition
contains a hydrated dicalcium phosphate abrasive or a dicalcium orthophosphate
dihydrate, the abrasive is incorporated in the second component of the dentifrice
composition of the present invention at a concentration of about I to about 60% by
weight and preferably at about 20 to about 50% by weight of the second component.
When the abrasive is an alkali metal bicarbonate salt such as sodium bicarbonate, the
bicarbonate salt is incorporated in the second component at a concentration of about 5 to
about 25% by weight.
Other specific examples of two component dentifrice compositions which may be
used in the practice of the present invention include dentifrice components Cont~ining
ingredients which are normally reactive and incompatible with each other such as calcium
cont~inin~ abrasives and polycarboxylated polymers (e.g., Gantrez) or potassium nitrate.
The reactive abrasive is contained in a vehicle formul~ted to have a compositionsimilar to the vehicle of the first dentifrice component, so that the two components will be
of similar physical characteristics, which will permit them to be more readily formulated to
~be coextrudable at substantially equivalent compressive forces. For example, in order that
the compressive force is substantially equivalent to extrude both components at a precise
predetermined ratio to effect optimum precipitation of calcium fluoride, the vehicle
composition of the second component, specifically the humectant content, is adjusted to
.
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accommodate the difference in component ingredients. Thus, in the exemplary two
component dentifrice in which one component contains fluoride and the other calcium
abrasive, the humectant content of the second component is adjusted to accommodate the
inclusion of the dicalcium phosphate abrasive. The abrasive is included in the second
S dentifrice component at a concentration of about 10 to about 30% by weight and
preferably at a concentration of about 15 to about 25% by weight. At these abrasive
levels, the humectant concentration ranges from about 15 to about 70% by weight and
preferably about 20 to about 40% by weight.
Similar adjustments in sodium bicarbonate concentrations in the second dentifrice
component of the multicomponent dentifrice used in the present invention can be made so
that the compressive forces required to extrude both components are substantially
equivalent to provide component dispensing at a predetermined ratio to effect optimum
reaction and effervesce between the bicarbonate ingredient in the second component and
the organic acid or peroxide ingredient in the first component.
A striped dentifrice product is obtained in accordance with the practice of the
present invention wherein colorants of contrasting colors are incorporated in each of the
dentifrice components used in the practice of the present invention, the colorants being
pharmacologically and physiologically non-toxic when used in the suggested amounts.
Colorants used in the practice of the present invention include both pigments and dyes.
Pigments used in the practice of the present invention include non-toxic, water
insoluble inorganic pigments such as titanium dioxide and chrornium oxide greens,
ultramarine blues and pinks and ferric oxides as well as water insoluble dye lakes prepared
by ext~n-ling calcium or ~h1mimlm salts of FD&C dyes on alumina such as FD&C Green
# 1 lake, FD&C Blue #2 lake, FD&C R&D #30 lake and FD&C # Yellow 15 lake. The
pigments have a particle size in the range of 5-1000 microns, preferably 250-500 microns,
and are present at a concentration of 0.5 to 3% by weight.
The dyes used in the practice of the present invention are distributed uniformlythroughout the dentifrice component and are generally food color additives presently
certified under the Food Drug & Cosmetic Act for use in food and ingested drugs,including dyes such as FD&C Red No. 3 (sodium salt of tetraiodofluorescein). FD&C
Yellow No. 5 (sodium salt of 4-p-sulfophenylazo-1 -p-sulfophenyl-5-hydroxypyrazole-3
carboxylic acid), FD&C Yellow No. 6 (sodium salt of p-sulfophenylazo-B-naphtol-6-
monosulfonate), FD&C Green No. 3 (disodium salt of 4-{~4-(N-ethyl-p-
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sulfobenzylamino)-phenyl]-(4- hydroxy-2-sulfoniumphenyl)-methylene}-[1-(N-ethyl-N-p-
sulfobenzyl)-~-3,5-cyclohexadienimine], FD~C Blue No. 1 (disodium salt of
dibenzyldiethyl-diaminotriphenylcarbinol trisulfonic acid anhydrite), FD&C Blue No.
2(sodium salt of disulfonic acid of indigotin) and mixtures thereof in various proportions.
The concentration of the dye for the most effective result in the present invention is
present in the dentifrice composition in an amount from about 0.0005 percent to about 2
percent by weight.
It is preferred that the colorant included in one of the dentifrice components be a
pigment such as TiO2 and that colorant distributed throughout the body of the other
dentifrice component be a dye and the dye be of a different color than the pigment
included in the first dentifrice component.
Any suitable flavoring or sweetening material may also be employed. Examples of
suitable flavoring constituents are flavoring oils, e.g., oils of spearmint, peppermint,
wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon, and orange,
and methyl salicylate. Suitable sweetening agents include sucrose, lactose, maltose,
sorbitol, sodium cycl~m~tf~, perillartine, and sodium saccharin. Suitably, flavor and
sweetening agents may together comprise from 0.01% to 5% or more ofthe preparations.
Various other materials may be incorporated into the dentifrice components of this
invention. Non-limiting examples thereof include preservatives, silicones and chlorophyll
compounds, antibacterial agents such as chlorohexidene, halogenated diphenyl ethers such
as triclosan, desensitizing agents such as potassium nitrate and potassium citrate and
mixtures thereof. These adjuvants are incorporated in the dentifrice components in
amounts which do not substantially adversely affect the properties and characteristics
desired, and are selected and used in proper amounts, depending upon the particular type
of dentifrice component involved.
To prepare the individual dentifrice components of the present invention, the
humectants e.g. glycerin, polyethylene glycol ingredients and sweetener are dispersed in a
conventional mixer until the mixture becomes a homogeneous gel phase. lnto the gel
phase are added the fluoride salt or dicalcium phosphate abrasive. These ingredients are
mixed until a homogeneous phase is obtained. Thereafter the thickener, flavor and
3 5 surfactant ingredients are added and the ingredients mixed at high speed under vacuum of
about 20-100 mm Hg. The resultant product is a homogeneous, semi-solid, extrudable
paste product.
11
.
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The Dispensing Container
The material from which the body side walls of the multicompartmented container
used in the practice of the present invention is manufactured is a flexible, resilient plastic
material which is deflected when a force is applied to the web. In the practice of the
present invention plastic web materials which deflect upon the application of a Deflective
Force of about 1.0 to about 3.0 pounds applied thereto have been found to be particularly
suitable for codispensing dentifrice components from collapsible compartmented tubes in
constant predetermined proportions in accordance with the practice of the present
invention.
The term "Deflective Force" as used herein and in the appended claims means the
maximum force expressed in pounds required to deflect a plastic web bent in the form of
an inverted U by a shaped adapter fitted to a compression table such as an lnstron~
Tensile Testing Machine? the force being applied axially downward on the arcuate section
of the U-shaped web at a rate of 12 inches per minute.
The adapter installed on the Instron~ Machine is 5.5 inches high and consists of a
0.25 inch thick stainless steel block, I inch square, with a 0.125 inch diameter stainless
steel wire curving downwardly to an open rectangular section 5 inches wide and 2.5
inches high. The adapter is fitted into the jaws of the Instron~ Machine and is moved
downwardly to contact and deflect the surface web being tested.
The plastic web being tested is held in a specimen holder consisting of a stainless
steel base 0.125 inches in thickness having a slot I inch wide, 4 inches long and 2 inches
high. A lower mount for this base, one inch in length, mounts the base to the work
platform of the lnstron~) Machine. A specimen brace fits into the base to hold the plastic
web in the base, the brace consisting of a channel 4 inches in length, 0.975 inches wide
and 2 inches high having a wall thickness of 0.625 inches. The specimen brace holds the
web in the base in an inverted U shape.
When making a measurement of Deflective Force, six plastic web specimens cut in
.the machine direction and six plastic web specimens cut in the cross direction, each
specimen being 4 inches X 4 inches, are tested. Each specimen being tested is placed in
the specimen holder and held in place by the brace so that it forms an inverted U shape.
No specimen sample is reused. The specimen holder with the sample is placed in the
12
. . ~
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Instron~ Machine and the adapter lowered to just above the specimen and then lowered
at the rate of 12 inches per minute to effect a web deflection of 0.35 inches. The force in
pounds to deflect the web in this manner is recorded as the Deflection Force.
The plastic sheet material from which the body sidewalls are manufactured may bemade of any suitable plastic material such as polyethylene (both low and high density)
polypropylene, ethylene and propylene copolymers and polyethylene terephthalate. The
plastic sheet material may have a l~min~te structure wherein a gas barrier material such as
ethylene vinyl alcohol, nylon or polyvinylidene chloride is sandwiched between layers of
polyethylene or polypropylene or copolymers thereof. The gas barrier materials prevent
the loss of certain ingredients of the dentifrice components which enter the gas phase and
permeate through the plastic materials of non-gas barrier structures.
The multicompartment container of the present invention has collapsible outer
sidewalls and a moveable partition dividing the container into a plurality of compartments
whereby the outer sidewalls of the compartments are collapsed to eject, under a
compressive force applied to the outer walls, the dentifrice components from theindividual compartments with the moveable partition compen.~ating for the deformation of
the outer walls of the tube whereby the compressive forces applied to the individual
dentifrice components for extrusion thereof from the container are equalized.
rN THE DRAWlrNG
Referring to the accompanying drawing in which corresponding and like parts are
decign~ted throughout the several views by the same reference characters.
Fig. I is a side elevation of one embodiment of the multicompartment container, a
collapsible tube, used in the practice of the present invention.
Figure 2 is a vertical longitudinal sectional view taken along line 2-2 of Figure I of
the multicompartmented tube.
Figure 3 is a transverse sectional view, along line 2-2 of Figure 2 with the tube in
uncollapsed condition.
Figure 4 is a view of the tube section shown in Fig. 3 in a collapsed condition.
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In Figure 1 there is illustrated a multicompartmented tube useful for storing and
physically segregating dentifrice components which contain reactive ingredients. The tube
shown in Figs. 2-4 includes a tubular body ] 0 which is shown with a circular section but
it could have another shape for example, oval. The tube has a body 10 which is of a type
S that is easily squeezable, compressible or collapsible and is comprised of a sidewall 12
formed from a resilient plastic material that can be deflected by Deflective Force of about
1.0 to about 3.0 pounds as hereinbefore described. One end 20 ofthe body 10 is sealed
while the opposing end 22 is open and is provided with a neck 22a through which the
components of the multicomponent dentifrice are discharged through aperatures 23 and
23a. The neck 22a is provided with eng~ging means to accept a closure cap (not shown).
The thickness of sidewall 12 will typically be in the range of about 0.25 to about
1.20 mm. In a preferred embodiment ofthe invention, the thickness ofthe sidewall 12 is
about 0.25 to about 0.35 mm in thickness.
ln the embodiment illustrated, the interior of the body 10 is segmented
longitudinally into two compartments 14 and 16 by means of a membrane or partition 18.
The partition 18 is flaccid and laterally moveable. Depending upon the construction of the
body 10, the partition 18 may be integrally formed with walls of the body 10 as a uniform
part of the body 10. Alternatively, the partition 18 may be a separately formed member
appropriately retained within the container body. In particular, when the body 10 and
partition 18 are fabricated from a thermoplastic material such as polyethylene, heat or
adhesive sealing may be used to join the two halves of the body 10 together with the
partition 18 joined to the peripheral margins ofthe sidewall 12. The peripheral edges of
the partition 18 are held permanently m~int~ined to the internal surface sidewall 12 by a
suitable thermal fusion bond or adhesive bond.
In Figure 2, the partition 18 is shown longitudinally in a corrugated or pleatedconfiguration so that as the outer walls of the tube are compressed or deformed, the
partition 18 will be caused to move laterally.
ln Fig. 3, the partition 18 is shown in its original, resting position prior to the
compression of the container sidewalls 12 and Fig. 4 shows partition 18 displaced laterally
to a position shown in phantom lines when the collapsible container sidewalls 12 are
compressed to codispense the individual dentifrice components from compartments 14
and 16.
14
.
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The partition 18 is comprised of a very flexible and flaccid thermoplastic film
material such as low density polyethylene or polypropylene or may be a laminate in which
a gas barrier layer is sandwiched between opposed polyethylene or polypropylene layer.
The partition 18 has a thickness substantially less than that of the plastic material from
S which the sidewalls 12 are formed and generally has a thickness of from 0.005 to 0.20 mm
and preferably about 0.075 to about 0.15 mm.
The bottom 20 of the body 10 may have any suitable configuration. The bottom
of the body 10 is sealed by crimping or squeezing together with the walls of the body 10
being adhesively or thermally bonded together and to the internal partition 18.
The compartments 14 and 16 of the container body 10 are filled with the dentifrice
components in the usual manner before the end 20 of the body 10 is sealed i.e., the
container is provided with a sealing cap (not shown); then inverted and filled through the
bottom end. The dentifrice components containing different reactive ingredients will
exhibit di~erel,~ flow characteristics when a compressive force is applied to the sidewall
12, as the dentifrice components as they flow over the interior sidewall surfaces encounter
dirrel enl, i.e., greater or lesser resistance to flow when compared to the other. To
compensate for this difference in flow in response to the compressive force applied, the
dentifrice components are formulated to account for this difference so that the
compressive force required to cause both components to flow is substantially equivalent,
the Compressive Force required typically being in the range of about 0.5 to about 20 Ibs
and preferably about I to about 10 Ibs. When a compressive force in this range is applied
to the container sidewalls 10, as by squeezing the container sidewalls, the individual
dentifrice components are caused to ~imlllt~neously flow. The partition 18 will move
laterally from its fixed position in response to any pressure differential existing in the tube
interior whereby the differences in compressive force are equalized. In the event that the
difference in Compressive Force required to extrude the individual components is in
excess of 20% and cannot be compensated for dentifrice formulation modification, the
difference in compressive force required for extrusion may be adjusted by modification of
the geometry of the aperture 23, 23a through which the individual components areextruded.
After the multicompartmented container has been filled, partition 18 is, as shown
3 5 in Figs. 2 and 3, substantially collapsed so that it can be displaced in either direction by a
pressure differential across it. In Fig. 4, the partition 18 is shown as shifting laterally to
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W097/46462 PCT~US97/08622
the right in response to a compressive displacement of the left side of the tube which is
greater than the compressive displacement of the opposite sidewall.
As the components are extruded out of neck 22a through apertures 23, 23a from
compartments 14 and 16, the individual components converge to form a single, banded
stream of material. The single stream is convenient and easy to direct with accuracy upon
a limited surface area, which in the case of toothpaste components can be neatly and easily
applied onto the narrow width of a toothbrush in proportions predetermined to provide
optimum therapeutic delivery of the reacted ingredients when the component layers are
mixed by brushing the teeth or other dental tissue in the oral cavity.
In operation, container 10 may be squeezed intermittently to dispense small
portions of the components of a two component dentifrice housed in compartments 14
and 16. When such containers are grasped by a variety of users having individual grips,
l S such squeezing can develop greater pressure on one component than the other. When this
occurs, the pressure differential across partition 18 displaces panition 18 until the
pressures equalize. Thus, partition 18 is a pressure responsive displaceable wall for
equalizing component pressures whereby a relatively constant proportion of a co-dispensed product components is achieved, as both dentifrice components are form~ ted
to be extrudable by the same compressive force, their relative extrusion rates will be
equalized by the moveable partition 18.
The diameter of the emerging single stream may be regulated according to
packaging specifications by adjusting the diameter of apertures 23 and 23 a . Generally the
stream is in the form of a cylindrical ribbon having a diameter of about 0.3 to about 2.0
cm. If different colorants are included in the individual dentifrice components, the
multilayer dentifrice component stream emerges from the neck outlet passage as an
attractive striped toothpaste.
The following example illustrates but does not limit the invention. Unless
otherwise indicated, all percentages are by weight and all temperatures are in ~C.
Example
3 S A series of 40 mm diameter dual compartmented tubes having a body length of
158 mm was formed from a l~min~ted sheet having the structure PE/EVOH/PE whereinPE is polyethylene and EVOH is an ethylene/vinyl alcohol copolymer, the sheet having a
16
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thickness of 0.3 mm. When tested, a Deflective Force of 1.6 Ibs was required to deflect
the sheet as determined using the Instron~ Machine in accordance with the procedure
previously described.
S The tube was segmented longitudinally into two compaltments of approximately
similar volume by means of a pleated partition film formed from polyethylene, having a
thickness of 0.12 mm which deflected upon the application of a Deflective Force of 0.077
Ibs.
The compartments of the dual compartmented tubes were filled with dentifrice
components dçcign~ted I and 2 of a multicomponent dentifrice designated "Dentifrice A"
which contained the ingredients listed in Table 1.
The viscosities of the two dentifrice components when measured in Brookfield
Units using a Brookfield(~) RVT Viscometer-E spindle at 5 rpms were substantially
equivalent, the viscosity of component 2 being 17% less than component I .
TABLE I
Dentifrice A
IngredientComponent l Component 2
Wt% Wt. %
Silica Fonnula Dical Formula
Sorbitol (70%) 36.36 --
Glycerine 10.00 22.0
Polyethylene ~Iycol-600 3.00 --
Carra~eenan gum 0.60 0.92
Avicel RC591-F 0.30 --
Tetrasodium pyrophospllate 0.50 0.25
TiO2 0.30 --
Sodium saccharin 0.25 0.20
NaF 0 510
Dicalcium P' ~cph~t~. 48.76
Silica abrasive 22.0 --
Silica thickener 2.50 --
Color o 03
Flavor oil 0.95 0.89
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Sodium laurvl sulfate 1.20 1.2(
Deionized water Q S. Q.S.
Viscosily~ Brookfield Units 42 3~,
The Compressive Force, as determined by the procedure previously described, to
cause components 1 and 2 of Dentifrice A was substantially equivalent, that is, the
Compressive Force required to extrude component I of Dentifrice A was 2.4% less than
component 2. The Compressive Forces required to extrude components I and 2 of
Dentifrice A are recorded in Table III below.
For purposes of comparison the procedure of the Example was repeated except a
comparative multicomponent dentifrice dçsi~n~ted "Component B" was used. The
ingredients of components I and 2 of col,lpal~live Dentifrice B and their viscosities are
recorded in Table Il below.
The Compressive Force required for extrusion of the individual components of
Dentifrice B were not within +20% of each other, namely component 2 of Dentifrice B
required a Compressive Force which was 45% lower than that of component 1. The
Compressive Force required for extrusion of the components of Dentifrice B are recorded
in Table III below.
The viscosity of component 2 of comparative Dentifrice B was substantially
equivalent to that of component 1, component 2 having a viscosity that was 12% lower
than that of component 1.
TABLE n
Dentifrice B
Ingredient Co~, 1G)~ 12
Wt.% Wt.%
NaF -- 0.486
S~cch~nn 0.20 0.20
Sorbitol -- 38.524
Glycerin 22.00 25.00
Polyeth~lene ~Iycol 600 -- 3 00
Dicalcium phl~cphn~e 48.76 --
Silica Abrasive -- 18.0
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Silica Thickener -- 5 :50
Flavor ().X9 0.89
Sodium lauryl sulfate 1.2() 1.2()
TiO2
CarboxYmetllyl cellulose 1.0() --
Water 25.75 --
Tetrasodium pyrophosphate 0.25 --
Viscosity. BrookfieldUnits 65 58
19
...... .....
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TABLE 111
Compressive Force
Required for Extrusion (Ibs)
Dentifrice A Dentifrice B
Component ] 2 53 5 5
Component 2 2 59 10 0
Components 1 and 2 of Dentifrice A were determined to dispense substantially
equally form the multicompartment tubes in which they were housed whereas components
I and 2 of Dentifrice B did not, although in both Dentifrices the viscosities of the
individual components were substantially equivalent.
