Note: Descriptions are shown in the official language in which they were submitted.
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MASTICATION ARTICLES POSSESSING
MICROBE-INHIBITING PROPERTIES
This application claims the benefit of provisional patent application Serial
No.
60/043,014 filed 4/15/97.
Field of Invention
This invention relates to a mastication article, principally for domestic
animals, and more particularly to a mastication article having a microbe-
inhibiting
agent or property that substantially inhibits the proliferation of microbes
on, within, or
around the mastication article. The term "microbe" herein refers broadly to
classes of
bacteria, viruses, germs, molds, mildew, fungi, allergens, and other
microorganisms.
An article of the present invention provides both comfort and health benefits
to both
pets and people involved with the use of such an article.
Description of the Related Art
Mastication articles are very popular with pets, and especially so with dogs.
There are two basic types of mastication articles: digestible and non-
digestible. The
prototypical digestible type is "rawhide" or rawhide-derived; but starch- or
seed-based
or other digestible materials may be used as well. The non-digestible type is
more
variegated, and may include alone or in part components comprised of molded
plastic,
rope, textile fabrics, fiber-fill, foam, as well as other components.
Mastication articles can provide therapeutic as well as amusement value to the
pets that chew on them. The mastication provides a degree of exercise and
cleans and
massages the teeth and gums of the pet; and, pets (especially dogs) seem to
enjoy
mastication on things. In addition, giving pets desirable articles on which to
chew
may preclude them from mastication on other things which may be harmful to
them or
would upset the pet's owner.
Mastication articles for pets tend to become messy and unsanitary as the pets
chew on them. There is also a risk of microbial proliferation on or within the
mastication articles during their storage. Both of these factors are
especially
problematic for digestible mastication articles, which provide ample
nutritional
resources for the abundant proliferation of microbes. It is therefore useful
and
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valuable to provide sanitary mastication articles which are resistant to the
proliferation
of microbes and optionally to odors. Because pets chew continually upon these
articles, and because pets can eventually digest these articles (even when
they are not
intended for digestion), toxicity considerations with regard to the microbe-
inhibiting
treatment are important.
Of the digestible type, rawhide is the most popular type of mastication
article.
Ready-to-use rawhide may be acquired commercially in a variety of forms and is
manufactured from animal (preferably cattle) hides by methods known in the Art
(see,
e.g., U.S. Patent No. 5,114,704). The manufacturing process generally consists
of
several steps. After the raw hides are obtained, they are usually treated in a
lime-
based solution (liming), the primary object of which is to loosen the hair on
the hide.
To the solution may be added ammonium salts, sodium sulfide, or other
additives.
After the liming treatment, the hair is removed from the hide, either by hand
or using
a dehairing machine. In the next step, known as "fleshing," tissue is removed
from
the flesh side of the hide. This may be performed with a special knife or with
a
fleshing machine. It is then necessary to ensure that all of the lime is
removed from
the hide. Washing in water can remove much of the lime, but it is generally
necessary
to use a more aggressive treatment with acids or acid salts to remove the
remainder.
After the hides are dehaired, fleshed, and cleaned, they may be cut into the
desired shapes and manipulated. Drying may be done in ambient air or
preferably in
an oven at elevated temperatures (usually less than 150°C).
U.S. Patent No. 5,310,541 discloses a rawhide animal chew intended to inhibit
oral pathogens from proliferating in a dog's mouth. The rawhide is treated
with
enzymes which are released into the dog's saliva upon mastication. Once in the
dog's
saliva, these enzymes set of a chain of reactions which attack oral pathogens
present
in the dog's mouth. Thiocyanate and iodide additives may optionally be added
to
enhance this effect.
U.S. Patent No. 5,476,069 discloses a molded rawhide mastication article, in
which rawhide is ground into small pieces and then injection molded at high
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temperature and pressure. The addition of casein and gelatin before injection
are said
to facilitate molding.
U.S. Patent No. 4,419,372 discloses a simulated rawhide mastication article in
which a mixture comprising an oil seed protein, a polyol plasticizer,
lecithin, and
water are extruded into a ribbon. The ribbon is then "sandblasted" (e.g.,
using ground
walnet) to impart a rawhide-like texture to the surface. The material is then
shaped or
cut in a manner similar to those for real rawhides.
U.S. Patent No. 5,407,661 discloses a non-rawhide digestible mastication
article for a pet in which a starch, a cellulosic fibrous material (e.g., corn
cob
fractions), a humectant, a proteinacious binder and a tarter-control oral care
additive
are mixed together and extruded in such a manner that the extrudate possesses
an
open, cellular structure.
U.S. Patent No. 5,419,283 discloses a molded mastication article for an animal
comprising a starch material and a biodegradable ethylene copolymer. Other
edible
materials can be added as plasticizers or as lubricants. These materials are
mixed in
the presence of water for subsequent injection molding into desired shapes
(e.g., a
bone).
Mastication articles of the non-digestible type are considerably more
variegated than are those of the digestible type. They may be comprised of
solid
molded plastic, hollow molded plastic, textile fabrics, rope-materials,
synthetic or
natural fiber-fill, foams, etc. They generally possess a texture and structure
which
combine to create a desirable "mouth-feel" for the pet (this is especially
important if
the article possesses no attractants (e.g., a meat scent).
U.S. Patent No. 4,557,219 discloses a molded polyurethane mastication article
for a pet in which has been incorporated a surface-migrating flavoring
extract.
U.S. Patent No. 5,477,815 discloses a mastication article for a dog comprising
a composite rope, where an inner core of the rope is comprised of brittle,
frangible,
and non-water absorbing threads (optionally with a flavoring extract), and the
outer
shell is comprised of soft, pliable cotton. The inner core is said to give the
article a
"crunchy" sound and texture and to aid in the dog's passing of the article if
it should
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be eaten. It is said that the non-water-absorbency of the inner core material
promotes
faster drying of the outer water-absorbing cotton material; and it thereby
inhibits
bacterial growth in the cotton. U.S. Patent No. 5,467,741 discloses a similar
invention, but includes the incorporation of therapeutic dental agents and/or
breath-
freshening agents in the inner core.
U. S. Patent No. 5,477,815 discloses a molded bone-shaped mastication article
for a dog which has relatively sharp, conically-shaped spikes distributed over
its
surface. The spikes serve to remove tartar or plaque from the dog's teeth as
the dog
chews on the toy. The material comprising the mastication articles is a rigid
polymer,
such as a rigid polyurethane or a rigid polyamide. A meat scent or flavor is
optionally
added to the article to increase its attractiveness to dogs.
U.S. Patent No. 5,477,815 discloses a molded mastication article for a dog
which is constructed from a synthetic thermoplastic material (e.g.,
polyurethane) in
which an animal meal (e.g., chicken meal, fish meal, etc.) has been
incorporated prior
the molding process.
U.S. Patent No. 5,477,815 discloses a molded mastication article for a dog
comprising water absorbing nylon in which at least a surface layer has been
incorporated with sugar.
Despite the desirability of effective microbe-inhibiting mastication articles
for
pets, no practical solutions have been proposed which would provide effective
and
continually present protection against microbial proliferation in or on the
articles. The
only two inventions which even remotely relate to microbe inhibition are given
in
U.S. Patent No. 5,477,815 (and its related continuations and divisions), which
only
claims to speed the drying of a rope-based article and thereby shorten the
period of
time it is most susceptible to microbial proliferation; and U.S. Patent No.
5,310,541,
in which the rawhide is a carrier for an enzyme to be released into a dog's
mouth. In
the latter invention, the rawhide is only a vehicle for delivering a reaction-
initiating
enzyme into the dog's mouth. The enzyme, which is inactive with respect to
microbes, reacts with the salivary solution in the dog's mouth, ultimately
resulting in
the temporary creation of ions in solution which attack oral pathogens in the
dog's
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mouth; and these ions can exist only in the dog's saliva. The rawhide article
itself
therefore contains no species which will inhibit subsequent microbial
proliferation in
and on the article (any such species which are transferred to the article from
the dog's
saliva will soon dry-up and thus become ineffective).
Thus, there is a need in the art for mastication articles for pets, where the
proliferation of microbes is prevented in and on the articles; where the
microbe-
inhibiting properties of the articles are continually active and durable;
where these
articles are desirable and attractive to the pets for which they are intended;
and where
these articles are safe for pets and humans.
I O SUMMARY OF THE INVENTION
According to the invention, mastication articles for pets have an effective of
amount of microbe-inhibiting agent or property that is effective in limiting
microbial
proliferation, and at the same time is not present in quantity, concentration,
or nature
whereby the articles may be harmful to the pets or humans who come into
contact
15 with the articles. The effective amount of the microbe-inhibiting agent or
property
limits the spread of the microbe-inhibiting chemicals or agents within and
about the
article, and takes into consideration the patterns of use and material
structure of the
article. The microbe-inhibiting agent or property can be at least one of a
microbe-
cidal, microbe-starving, and microbe-impenetrable agent. Furthermore, the
material
20 comprising the mastication article can be selected from a group consisting
of animal
skin, animal fat, vegetable, or some blend thereof, if a digestable
mastication article is
desired. Another embodiment of a mastication article is comprised of material
selected from a group consisting of polymeric resins or solutions, fibers or
threads,
textile materials, foams, or some blend thereof, if a non-digestable
mastication article
25 is desired.
Another embodiment of a mastication article includes a microbe-inhibiting
agent as a particulate incorporated into the material comprising core
particles over
which is coated with a microbe-inhibiting active layer. The core particles are
selected
from a group comprising zinc oxide, titanium. barium sulfate, or a blend
thereof. The
30 active layer is selected from a group comprising silver, copper oxide, zinc
silicate, or a
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blend thereof. In a further embodiment, the active layer includes a barrier
coating,
whereby the rate of release of the microbe-inhibiting agent or property can be
controlled. Also, the active layer may include a dispersion coating, whereby
the core
particles in the material are dispersed.
Another embodiment of the article is a mastication article comprising rope,
wherein the rope can be made of a material selected from a group, cotton,
sisal, hemp,
jute, henequen, or a blend thereof. Furthermore, the mastication article made
from
rope may include a core made of a hydrophobic material such as nylon.
Another embodiment is a mastication article made of a material selected from
the group including nylon, polyurethane, polyoleflns, or a blend thereof. Such
a
mastication article may include a nutritive attracting agent within the
material. Such a
nutritive attracting agent is selected from a group including animal meal,
meat broth,
dried meat, sugar, or a blend thereof.
Further, according to the invention, there is provided a method for producing
a
mastication article having a tough, chew resistant material and defining a
shape in the
form of a small article for enticing or being retrieved by a domestic animal,
the
method incorporating the step of applying an effective amount of a microbe-
inhibiting
agent to the material comprising the mastication article. The microbe-
inhibiting agent
can be applied to the mastication article by dissolving the agent in a
solution, which is
then applied to the article, either by soaking the mastication article in the
solution or
spraying the mastication article with the solution.
A further embodiment of the process for producing a mastication article
includes applying the microbe-inhibiting agent by coating the material with a
microbe-inhibiting active layer, wherein the microbe-inhibiting agent is a
particulate
incorporated into the material and comprising core particles. The core
particles are
selected from a group including zinc oxide, titanium oxide, barium sulfate, or
a blend
thereof. The process may include the additional step of incorporating the
particles
into a resin for plastic processing of the mastication article. Alternatively,
the
particles can be incorporated into a dope before fiber spinning the
mastication article.
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In a further embodiment, the particles are incorporated into a spray for
coating the
mastication article.
Another process according to the invention includes the step of applying the
microbe-inhibiting agent to a rawhide material during cleaning of the rawhide.
Alternatively, the microbe-inhibiting agent can be applied to the rawhide
material
during liming of the rawhide material.
In any of the processes described above, a nutritive attracting agent
imparting
a flavor or smell to the mastication article can be incorporated into the
material.
Furthermore, for any of the processes outlined above, the microbe-inhibiting
agent
can be applied to the material comprising the mastication article at a
temperature
between 40 - 100°Celsius.
For a mastication article comprising cotton rope, a process according to the
invention includes a step of applying moisture to the cotton rope as it is
being formed,
and then spraying the cotton rope with a solution including the microbe-
inhibiting
agent, whereby the cotton rope is more absorptive of the micro-inhibiting
agent.
Where the process according to the invention includes forming the mastication
article of a material including fibers, the application of the microbe-
inhibiting agent
can be accomplished by incorporating the agent into a portion of the fibers,
and then
dope spinning the fibers.
Where the process according to the invention includes molding the mastication
article, the step of incorporating the microbe-inhibiting agent can include
adding a
resin having a microbe-inhibiting agent therein to material for forming the
mastication
article.
Where the process of the invention includes a latex mixture for forming the
mastication article, the microbe-inhibiting agent can be added to the latex
mixture
before molding the article.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is perspective view of a first embodiment of a mastication article
according to the invention;
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FIG. 2 is perspective view of a second embodiment of a mastication article
according to the invention;
FIG. 3 is a sectional view the mastication article of FIG. 2;
FIG. 4 is a perspective view of a third embodiment of a mastication article
according to the invention; and
FIG. 5 is a sectional view of the mastication article of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1-5, several embodiments of a mastication article are
shown. In FIG. 1, a first embodiment of a mastication article 10 made of a
tough
chew-resistant rawhide material 12 is shown. The rawhide material 12 includes
a
microbe-inhibiting agent applied to or incorporated therein, as will be
discussed
further below. A second embodiment is a mastication article 20 made of a rope
material 22, as shown in FIG. 2. The rope material 22 preferably comprises
cotton,
and is treated with a microbe-inhibiting agent as will be described below. As
shown
in FIG. 3, the mastication article 20 may include a core 24 comprising a
different
material, usually a hydrophobic material such as nylon. FIG. 4 shows another
embodiment of a mastication article 30 made of a plastic material 32. The
mastication
article 30 may be hollow, having a open center 34, as shown in FIG. 5, or
solid (not
shown), and is treated with a microbe-inhibiting agent during formation, as
will be
described below.
The term "microbe-inhibiting" in the present disclosure subsumes all
characteristics (and the means for imparting these characteristics) which
cause the
mastication articles to be inhospitable to microbes. Distinctions may be made
between three types of microbe inhibition:
Microbe-cidal refers to a property whereby microbes are actively killed or
otherwise rendered ineffective. If a microbe comes within a sufficiently close
range
(direct contact, for some materials; within a "zone of inhibition" for others
) of a
microbe-cidal material, it will be killed or otherwise rendered ineffective.
Microbe-
cidal properties may be imparted to materials by a variety of means. A
preferred
means uses microbe-cidal agents during the manufacturing process of the
materials
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and/or treats the materials with microbe-cidal agents. A number of preferred
agents
are disclosed below. For the microbe-cidal property to be durable, it is often
preferred
that the agents be bonded in some manner to the materials comprising the pet
article.
Such materials exhibit smaller zones of inhibition than materials containing
non- or
weakly bonded agents, but the microbe-cidal property with regard to microbes
coming
directly into contact with the material can be more durable. Using agents
which are
insoluble or only sparingly soluble in water can also be a key element for
durability.
Microbe-starving refers to a property whereby microbes are controlled or
eliminated by deprivation of sources of nutrition. A material is said possess
microbe-
starving properties if microbes in contact with the material have difficulty
acquiring
the resources they need to survive. One can often provide or enhance a microbe-
starving characteristic to a material by changing or altogether eliminating
additives to
the materials (e.g., plasticizers, fillers, or processing aids). Since adhered
dust or
liquids can provide nutrition for microbes, it is preferred that the material
be provided
with anti-adhesion properties (e.g., anti-static, low surface energy, etc.).
Microbe-impenetrable refers to the property of a material or coating whereby a
microbe cannot pass through the material or coating. In this case, microbes
may
proliferate to some degree on a surface of the material, but such
proliferation will be
confined to the surface. Thus if an article is treated on its exterior by a
microbe-
impenetrable coating, microbes from the environment will not be able to pass
into the
interior of the article, will be limited in the degree to which they can
proliferate, and
can more readily be removed by washing. Appropriate placement of microbe-
impenetrable materials is important to their effectiveness in providing the
microbe-
inhibiting property.
It is often efficacious to fight the battle against microbial proliferation on
several fronts. Thus preferred microbe-inhibiting mastication articles for
pets will
often possess combinations of microbe-inhibiting behavior. For example, when a
particular component of a mastication article is most susceptible to microbial
attack,
this component may be treated with both a microbe-impenetrable layer and a
microbe-
cidal agent, while the remainder of the article is treated with only the
microbe-cidal
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agent. Further, an additive which serves as a resource for microbial growth
may be
important only for certain parts of the article. For example, plasticizers
often act as an
effective resource for microbial proliferation; and one can use the
plasticizer only
where the flexibility is needed, and then treat this area with an effective
combination
of microbe-inhibiting characteristics; and the remainder of the article, where
the
plasticizer was not used, may be less vigorously protected.
For durability, the microbe-inhibiting agents should not readily dissolve into
the fluids with which they come into contact. This includes fluids associated
with
their use (saliva, urine, or other bodily fluids) as well as washing and
cleaning fluids
(the microbe-inhibiting activity should be durable to repeated home
laundering). The
insolubility may be an intrinsic characteristic of the agent-fluid
combination, or it may
be due to the fact that the agents are well bonded to the materials comprising
the
article. Both types are included in the present invention.
Although both water-durable and non-water-durable microbe-inhibiting
components may be used with effectiveness in the present invention, if a non-
water-
durable microbe-inhibiting component is used, the exterior of the exposed
material
should desirably be provided with water-repellent or otherwise water-
insulating
qualities.
In a preferred class of embodiments, microbe-inhibiting properties are
conferred upon one or more of the materials comprising the pet article by
treating the
material with or otherwise incorporating into the material a microbe-
inhibiting agent.
This microbe-inhibiting agent is a chemical species or particle which imparts
to the
material an effective microbe-inhibiting property. The microbe-inhibiting
agents will
often function primarily through a microbe-cidal mechanism. The microbe-
inhibiting
agents are typically chemicals, polymers, solutions (solid or liquid), or
particulates
(which may possess their own microbe-inhibiting activity or may act as hosts
for other
microbe-inhibiting agents). These microbe-inhibiting agents may exist in a
variety of
forms and be held in a variety of hosts before being incorporated into the
mastication
article. For example, they may be dissolved in a liquid; they may be
incorporated in
or comprise the totality of a particulate phase, either dry or suspended in a
liquid; they
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may be included within a plasticizer compound; or they may be pre-incorporated
into
a material used in manufacturing the article (e.g., one may employ materials
which
already possess microbe-inhibiting properties).
Examples of chemical microbe-inhibiting agents for use in polymers may be
found in Plastics Additives and Modifiers Handbook, pp. 338-350, J. Edenbaum,
Ed.,
Chapman and Hall, Great Britain, 1996, and herein incorporated by reference.
The microbe-inhibiting treatment may be carried out at different points during
the process of manufacturing the article or its component materials. For
example, one
may incorporate microbe-inhibiting agents in fibers as they are being
manufactured,
which microbe-inhibiting fibers can be used as the filling of stuffed
mastication
articles or as the fabric used as the external covers of mastication articles.
One can
also manufacture a microbe-inhibiting elastomeric-like material for use in a
component of the mastication article which is comprised of (e.g., molded)
plastic.
One can also treat (as by spraying or soaking) some or all of the materials
after they
are partially or completely manufactured (e.g., one may soak rawhide sheets or
the
rope which will be later cut and formed into rope-bones in a microbe-
inhibiting
treatment solution; or one may treat the external cover andlor the filling or
some
component of the filling of a mastication articles before their final
assembly).
Alternatively or in addition, one may treat (as by spraying or dipping) the
pet article
when it is finished or nearly finished its manufacture. It is often preferred
to perform
soak treatments under elevated temperatures and/or pressures.
Microbe-inhibiting agents may be incorporated into the constituent materials)
of a mastication article by admixing the agent or a carrier for the agent with
the raw
ingredients to the material (e.g., add a liquid containing the agent to the
resin mix
before injection molded a plastic article). In this case, the microbe-
inhibiting agent is
usually dispersed relatively uniformly throughout the final material.
In cases where surface attachment is desired, the use of adhesion promoters is
preferred, particularly in conjunction with "raw" microbe-inhibiting agents,
i.e., those
which do not need to be in solution to work effectively.
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In cases where a bonding agent is not used to attach the microbe-cidal
functionality to the material of interest, or where such bonding is not
entirely
effective, it is often useful to diminish the rate at which the active microbe-
inhibiting
agent becomes de-activated. This may be done by inhibiting volatilization or
adding
stabilizers.
When the microbe-cidal agents are not bonded or are only weakly bonded to
materials comprising the mastication article, it is preferred to package the
articles such
that the effective shelf life of the antimicrobial character is enhanced. For
example,
when volatilization of the antimicrobial agent is a problem, the packaging
material
can be made impervious to the volatilizing material.
It is useful to have a microbe-inhibiting agent at the surface of the
mastication
article, as well as in the interior. The microbe-inhibiting agent at the
surface can be
effective in inhibiting the proliferation of microbes directly on the surface.
If suitable
microbe-inhibiting agents are present in the interior, they can migrate to the
surface as
the agent initially at the surface becomes displaced. This effectively
constitutes a
"time-release" of microbe-inhibiting agent. In this manner, the concentration
of the
agent may be maintained at a safe level, any odors associated with unduly high
concentrations of the agent are avoided, and the period of effective microbe-
inhibiting
protection can be considerably prolonged.
The microbe-inhibiting agent may be applied in a liquid form (as dissolved in
a solvent) and deposited on the surface of the mastication article material.
By
choosing properly the liquid, material, environmental conditions (e.g.,
temperature,
pressure) and optionally any additives, the agent can be made to penetrate the
material; and a "time-release" system may be obtained.
A "time-release" property may also be provided by incorporating the active
agent in a separate material, optionally particulate, which releases the agent
in a time-
controlled manner. For example, one can saturate a particulate zeolitic
material with a
microbe-inhibiting agent and incorporate the zeolitic material into the pet
article.
Alternatively, one can use a textile chosen specifically for its time-release
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characteristics for a particular microbe-inhibiting agent; and this textile
may be
incorporated in the mastication article.
If some form of heat-assisted disinfection of the articles is desired, it is
important to use material-agent systems which do not degrade in the
disinfection
environment (e.g., washers, microwave, thermal ovens, etc.). The softening or
decomposition temperatures of the polymers and chemical agents used, for
example,
must be higher than the disinfection temperature used.
Because the accumulation of undesired organic or inorganic matter may
reduce the efficacy of microbe-inhibiting protection, the articles may be
designed with
materials which reduce the tendency for such accumulation. This may be
accomplished by using low surface energy materials or applying a low surface
energy
coating; and/or by using anti-static materials or applying an anti-static
coating. Non-
hydrophilic materials (materials upon which water droplets form contact angles
greater than about 30 degrees) are generally preferred to prevent the adhesion
of such
undesired matter.
Pets, especially dogs, often tear or otherwise damage or digest the
mastication
articles which they use. It is therefore important that the materials be non-
toxic, non-
carcinogenic, and effectively non-allergenic at the levels used in the
articles. Some
agents are non-toxic even at relatively high concentrations (e.g., triclosan,
stabilized
chlorine dioxide); other agents are non-toxic at relatively low
concentrations, but
become toxic at high concentrations (e.g., many unbonded quaternary ammonium
compounds). If a mastication article employs a time release property, one must
ensure that the time-releasing materials do not contain concentrations of the
agents
which exceed those which can be safely eaten by the animal of interest. The
pet
should be able to eat the article without harm. Also, the treated materials
should be
non-skin-sensitizing, i.e., should not generally cause allergic or other
undesirable
reactions on the skin or other membranes of the pet or people who effectively
come
into contact with the materials.
Preparation of Materials
Unless otherwise stated, concentrations given herein are weight percent.
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Materials of the present invention may be made from natural animal products,
including skin and fat-based materials, natural vegetable products, polymeric
resins or
solutions, fibers or threads, textile materials, foams, and other materials.
At least
some fraction of the constituent materials are to be provided with microbe-
inhibiting
properties.
In preparing microbe-inhibiting synthetic materials derived from polymers, the
microbe-inhibiting agents are preferably added to the precursor material
(e.g., into the
resin mix for molded plastics or into the melt or spin dope from which fibers
are
spun). For natural materials, the microbe-inhibiting agents are preferably
either
impregnated into the materials via a spray or soaking treatment. Microbe-
inhibiting
agents or carriers with such agents can also be included in an admixture of
natural
and/or synthetic materials which are to be transformed into the finished
article.
Phenol derivatives, especially 2,4,4'-trichloro-2'-hydroxydiphenol (known as
Triclosan, Irgasan, Microban, etc.) are attractive and are preferred.
Organotins,
especially Tri-n-butyltin maleate (as in Ultra Fresh DM-50), are also
attractive and
preferred. Soak-treating in an aqueous solution containing stabilized chlorine
dioxide
is also preferred.
It is important to note that post-treatment methods involve importantly
different considerations when one is using a "strongly-bonded" type of agent.
In the
"diffusing" or "non-strongly-bonded" case, one immerses or otherwise exposes
the
materials to a solution containing a particular concentration of the agent.
Generally,
the agent diffuses into the material until its concentration in the material
is
comparable to the concentration in the solution, i.e., the treatment level of
the material
is essentially proportional to the concentration of the agent in solution; and
the agent
concentration in the solution is the primary controlling variable. In typical
treatments,
the agent in solution is not appreciably depleted; and the amount of material
exposed
to the treatment solution is not carefully monitored and is not considered a
primary
variable of the treatment process.
In the strongly-bonded case, however, the agent usually does not diffuse into
the material; rather, it chemically reacts with the surface of the material.
Here one
CA 02238122 1998-06-23
-15-
attempts to arrange conditions such that most of the "readable" agent present
in the
solution reacts with and bonds to the surface of the material being treated.
Knowledge of the amount of material being treated is thus crucial in
determining the
treatment level; and the material amount, along with the agent concentration
in
solution, are considered controlling variables of the treatment.
By the "amount of material," one really means the "amount of reactable
surface" of the material. For porous materials which can take up the solvent
in their
interiors (e.g., many natural materials such as cotton or rawhide, fabrics,
foams, etc.),
the mass of the material is often used as an indicator of the reactable
surface area -
i.e., one can specify an agent level in solution per unit weight of material
being
treated. For non-porous materials and/or materials which do not absorb the
solvent
being used (hard plastics, highly solvent-phobic materials), more direct
knowledge of
the reactable surface area is needed.
The preferred strongly-bonded agent for use in the present invention is 3-
trimethoxysilylpropyldimethyloctadecyl ammonium chloride (as in Dow Corning
5700).
For use in mastication articles which contain fabrics, microbe-inhibiting
fabrics may be constructed by weaving, knitting, or otherwise forming the
fabric from
fibers which possess the desired microbe-inhibiting properties. Alternatively,
the
fabrics can be post treated via spray-treating or by using a padding system
such as are
common in the art of textile finishing. For post treatment, Tri-n-butyltin
maleate (as
in Ultra Fresh DM-50) is a preferred diffusing microbe-inhibiting agent (at
fabric
pick-up about 0.1 %-.5%); and 3-trimethoxysilylpropyldimethyloctadecyl
ammonium
chloride (as in Dow Corning 5700) is a preferred strongly bonded microbe-
inhibiting
agent (at fabric pick-up about 0.08%-0.15%).
The preferred means for obtaining microbe-inhibiting foams is to include a
microbe-inhibiting agent in the formulation of one of the foam precursors
(i.e., before
the material is foamed). A preferred microbe-inhibiting foam is obtained by
adding
Ultra Fresh DM-50 to the polyurethane foam formulation before foaming
(typically in
amounts ranging from 0.04% to 0.6% relative to the total weight of the
formulation).
CA 02238122 1998-06-23
,., ~, , _16_
Another preferred means is to use Dow Corning 5701 (a reactive silane
quaternary
ammonium compound, which works much like Dow Corning 5700). This agent is
also added into the formulation of the foam before foaming (typically in
amounts
ranging from 0.1% to 1.2% relative to the amount of polyol).
Another preferable microbe-inhibiting agent is known by the trade name,
Intercept. It is a complex of polysubstituted imine salts and trialkyl
phosphate esters
with free alkylated phosphoric acid. It is relatively non-toxic; and it has
been used as
an antimicrobial finish on many building materials.
A further preferred type of microbe-inhibiting agent is typified by the
MicroFree brand of particulates (available from DuPont). These particulates
generally
comprise a core particle (zinc oxide, titanium oxide, or barium sulfate) over
which is
coated a microbe-inhibiting active layer (silver, copper oxide, and/or zinc
silicate). A
barrier layer (to control the rate of release of the active component) and a
dispersion
coating (to facilitate dispersion of the particles in host materials) are
included on top
of the active layer. The particles range from about 0.3~m to 1 ~m in size.
They can
be incorporated into many resin systems for plastics processing, into the dope
before
fiber spinning, and into many coating systems for post-treatment. Good microbe-
inhibiting efficacy can be imparted to various materials using these
particles; and the
resulting materials are generally non-toxic, very stable, and cost effective.
Other microbe-inhibiting agents may be used without departing from the spirit
of the present invention.
Rawhide Mastication Articles
For rawhide mastication articles, microbe-inhibiting characteristics may be
imparted to the rawhide by treating it with microbe-tidal agents (which are
discussed
herein) during the process of manufacture. This may be carried out during the
liming
or one of the cleaning phases; or an additional step may be added in which the
hides
are sprayed with or soaked in a microbe-tidal solution.
The rawhide may also be treated after it is essentially fully manufactured. In
its "hard" form, it may be sprayed with a microbe-tidal solution (which can be
allowed to soak-in), or it may be soaked in a microbe-tidal solution for a
time
CA 02238122 1998-06-23
.,, s, , _17_
sufficient for the microbe-cidal agents to infiltrate appreciably the rawhide.
In the
latter case, it will generally be necessary to dry the treated rawhide (in
ambient air or
in a furnace at elevated temperature).
It is necessary to ensure that the processing temperature, either during or
after
the microbe-inhibiting treatment, is not excessively high so as to inactivate
or
otherwise damage the microbe-inhibiting properties of the article.
Because dogs often eat rawhide, toxicity considerations are important. A
preferred agent for use with rawhide products is chlorine dioxide, which is
safe for
both animal and human consumption (e.g., it is used in mouthwashes,
toothpaste, and
as a drinking-water additive). An appropriate solution concentration is in the
range of
about 0.1-2%.
Also preferred is Ultrafresh DM-50. Water is the primary solvent for the
preferred treatment solution, which contains between 0.005%-0.4%, preferably
0.008%-0.1% ofthe DM-50 agent.
Also preferred is triclosan. It is generally desired to treat the rawhide so
that
the concentration of triclosan is between 0.01% and 1.2%, preferably between
0.05%
and 0.6%. An alcohol, preferably ethanol, is the primary solvent of the
preferred
treatment solution. When treating by soaking in a triclosan solution,
subsequent
rinsing in an aqueous solution is preferred.
It is generally preferred to treat the rawhide during its manufacture, i.e.,
before
the final drying step.
In some cases, it is preferred to post-treat finished rawhide. First, one must
"open-up" the rawhide structure. This is done by soaking the rawhide in water
or
other suitable non-toxic solvent (e.g., ethanol). The "opened" rawhide is then
placed
in the desired treatment solution for soaking. After sufficient time has
elapsed for the
rawhide to uptake an efficacious level of the microbe-inhibiting agent, it is
removed
from the treatment bath and dried. If the opening solvent and the treatment
solvent
are the same, one can combine the two steps (i.e., the treatment solution will
serve
also to open-up the rawhide).
CA 02238122 1998-06-23
. . . ~ . ' -1 g-
Adding an amount (typically 0.1-20%) of a soluble or dispersable polymer or
organic material to the treatment solution can assist in the retention of the
microbe-
inhibiting agent in the rawhide. For example, one can incorporate many
cellulose
ether materials (e.g., methyl cellulose, hydroxyethyl cellulose, or
carboxymethyl) or
poly (vinyl alcohol) in water-based solvents. Starches, agar, gelatin, casein,
lard, etc.
can also be useful. Butyl cellulose, among others, is soluble in ethanol, a
preferred
solvent for triclosan. Preferred microbe-inhibiting agents to be used with
retention-
assisting ingredients are triclosan, Ultra Fresh DM-50, and chlorine dioxide.
In retention aids in this manner, one must ensure that both the retention aid
and the microbe-inhibiting agent are sufficiently soluble or dispersable in
the solvent.
If it is desired to form molded rawhide articles, one typically begins by
cutting
or shredding conventional rawhide into small pieces. This process is often
facilitated
by first soaking the rawhide in a good solvent, such as water. It is often
preferred to
boil the rawhide in water before cutting it. The small pieces should then be
dried.
These dried small pieces can then be admixed with additives designed to give
the final product an improved "mouth feel." Casein, agar, gelatin, sugary
syrups (e.g.,
honey) are examples; they are typically added in an amounts such that there
total
fraction does not exceed about 10%.
The microbe-inhibiting agent is then added to this admixture. A preferred
agent is triclosan, added in a quantity such that its concentration in the
finished
product is between 0.001 % and 1 %, preferably between 0.004% and 0.1 %. It is
frequently preferably to dissolve the triclosan in a solvent before adding to
the
mixture; the preferred solvent is ethanol. Ultrafresh DM-SO is also preferred,
added in
a quantity such that its concentration in the finished product is between
0.001 % and
1 %, preferably between 0.004% and 0.1 %. It is frequently preferred that the
DM-50
be carried in a solvent, preferably water.
Chlorine dioxide dissolved in solvent is also preferred, added in a quantity
such that its concentration in the finished product is between 0.0001 % and
0.5%,
preferably between 0.001 % and 0.2%.
CA 02238122 1998-06-23
' ' -19-
The admixture is typically pre-heated to burn off a large part of the
remaining
solvents. The admixture is then fed into an inj ection molding machine under
elevated
temperature and pressure. It is desired that liquification occur. This
generally
requires pressures in excess of 60atm and temperatures in excess of 120C.
Pressures
and temperatures in the environs of 75atm and 145C, respectively, are
preferred.
Desired shapes are then molded.
Microbe-inhibiting molded rawhide can also be manufactured using other
techniques. For example, one can obtain finely divided rawhide by boiling the
rawhide; cutting it into small pieces; soaking the pieces in ethanol; drying
the pieces
in an oven; and grinding the rawhide in a coffee bean grinder. This finely
divided
rawhide can then be mixed with the desired microbe-inhibiting agent, a
solvent, agar
(or other degradable polymer), and optional flavoring additives. The mixture
can be
heated until it is quite thick, and then poured into a mold. Subsequent
heating will
further dry and congeal the product into a rawhide-based mastication article.
Articles
of this type, however, are generally much less tough than the injection-molded
type.
It is also useful to provide a spray bottle or the like containing microbe-
cidal
solution which the pet owner may apply periodically to the rawhide to refresh
its
microbe-inhibiting properties. In this case, an aqueous solution of chlorine
dioxide
(with concentration about 0.08-3%) is preferred. Ethanol solutions, used with
sufficiently low frequency and at sufficiently low concentrations so as not to
affect
adversely the animal, are also useful for this purpose. Other "natural
antimicrobials"
can also be used.
Rope-Based Mastication Articles
Cotton is a highly absorbent material and is particularly attractive for
constructing rope-based mastication articles; but when cotton becomes wet with
saliva, it tends to dry relatively slowly, which can lead to bacteria growth.
A "passive" approach includes limiting bacterial proliferation by limiting the
time for which the material is exposed to moisture is limited, such as by the
inclusion
of a nonabsorbent core for a cotton covered rope chew article. But the article
will
CA 02238122 1998-06-23
f . , _20_
frequently still be exposed to moisture for periods sufficiently long for
significant
bacterial proliferation to occur.
The present invention discloses an "active" and complete approach in which
microbe-cidal agents are incorporated into the article. In this way, the
article is
directly protected against the proliferation of a wide variety of bacteria, as
well as
other microbes, regardless of factors such as the specific environment or the
way the
dog uses the article.
A preferred means for treating cotton rope-based mastication articles for
pets,
or for treating rope-based mastication articles for pets in which cotton is a
major
component, is to soak the rope material in a solution containing Ultra Fresh
DM-50.
It is generally desired to treat the rope material in an aqueous solution such
that the
material pick-up of the agent is about 0.03%-1.2%, preferably between 0.08%
and
0.6%.
Another preferred means for treating cotton rope-based mastication articles
for
pets, or for treating rope-based mastication articles for pets in which cotton
is a major
component, is to treat in a solution containing Dow Corning 5700 strongly
bonded
microbe-inhibiting agent. It is desired that the material pick-up of the agent
be about
0.08%-0.15%.
Soak-treating in an aqueous solution containing stabilized chlorine dioxide
(concentration range about 0.1-4%) is also preferred. Also preferred is
triclosan. It is
generally desired to soak the rope material in solution in which the
concentration of
triclosan is between 0.01% and 1.2%, preferably between 0.05% and 0.6%. An
alcohol, preferably ethanol, is the primary solvent of the preferred treatment
solution.
The soaking (or spraying) solution can optionally contain ingredients which
will impart a desirable scent or flavor to the articles, such as meat broth,
meat meal,
gravy, etc.
It is generally preferred to that the treatment occur at elevated temperature,
typically between 40-100°Celsius. If a temperature higher than the
boiling
temperature of the primary solvent is used, however, increased pressured must
be
CA 02238122 1998-06-23
. , , r. , -21-
used. For example, the articles can be treated in an aqueous solution at
temperatures
exceeding 100C if an autoclave or pressure cooker is used.
Adding an amount (typically 0.1-20%) of a soluble or dispersable polymer or
organic material to the treatment solution can assist in the retention of the
microbe-
s inhibiting agent in the rope-material and is preferred. For example, one can
incorporate many cellulose ether materials (e.g., methyl cellulose,
hydroxyethyl
cellulose, or carboxymethyl) or poly (vinyl alcohol) in water-based solvents.
Starches, agar, gelatin, casein, lard, etc. can also be useful. Butyl
cellulose is an
example of a polymer which is soluble in ethanol, a preferred solvent for
triclosan.
Preferred microbe-inhibiting agents to be used with retention-assisting
ingredients are
triclosan, Ultra Fresh DM-50, and chlorine dioxide.
In retention aids in this manner, one must ensure that both the retention aid
and the microbe-inhibiting agent are sufficiently soluble or dispersable in
the solvent.
Many desired retention aids are easily digestible by microbes, and it is
therefore especially important to ensure that the microbe-inhibiting agents
are present
in the retention aids at concentrations sufficient to inhibit the
proliferation of
microbes.
The rope material may also be disinfected or sanitized prior to its treatment
by
soaking in a disinfecting solution (e.g., ethanol), optionally at elevated
temperature or
pressure.
The rope materials can also be sprayed with the treatment solutions.
After a soak or spray treatment, the rope material must be dried. Air-drying
and oven-drying are preferred, as is drying in a vacuum oven, optionally at
elevated
temperature.
Another preferred method for constructing a microbe-inhibiting cotton-rope-
based mastication article is to spray or otherwise expose the individual
filaments or
threads with the microbe-inhibiting agent (either in solution or carrier form)
as the
rope is being formed. In order to expand the threads and make them more open
to the
introduction of the microbe-inhibiting agents, it is preferable to expose the
threads to
moisture before the microbe-inhibiting agents are introduced. The microbe
inhibiting
CA 02238122 1998-06-23
r , _22_
agents may be introduced by spraying a solution containing the agent
(solutions with
concentrations similar to that of the soak-treatment solutions can be used)
onto the
filaments. The agents can be dissolved in solution or can be part of a
dispersion.
Other natural materials are useful in constructing rope-based mastication
articles for pets. These include sisal, hemp, jute, henequen, and others.
Ultra Fresh
DM-50 and Dow 5700 are the preferred agents for treating these materials.
Chlorine
dioxide and triclosan are also preferred.
Rope-based mastication articles can be made from a variety of synthetic
materials as well. They can be constructed, e.g., from fibers or threads
composed of
nylon, orlon or other acrylics, polyester, polypropylene, or other materials.
For these
materials, it is preferred to incorporate triclosan (or Microban or Irgasan)
at the time
of manufacture of the raw filaments. The agent is preferably incorporated into
the
melt or spin dope from which the filaments are drawn. It is preferred that the
concentration of triclosan in the finished filaments be between 0.01 % and
1.8%,
preferably between 0.05% and 1%.
A rope functionality may be combined with other functionalities to create an
improved mastication article. For example a hole can be punched through
microbe-
inhibiting rawhide articles of the present invention; and a microbe-inhibiting
rope of
the present invention may be threaded through the holes. The rope can then be
knotted at either end to secure the rawhide to the rope structure. Similarly,
a microbe-
inhibiting rope of the present invention may be threaded through a fiber-
filled plush
chew toy for a pet, where all or part of the fiber in the plush chew toy has
been
incorporated with triclosan microbe-inhibiting agent.
Plastic Mastication Articles
Plastic-based mastication articles for pets are becoming increasingly popular.
Except in some cases where degradable polymers are used, plastic-based
mastication
articles are not intended for digestion. Many non-digestible plastics possess
a
moderate natural microbe-starving quality - they provide little or no
nutritive material
for microbes to digest or metabolize and thereby thrive. Even with these
articles,
however, saliva and other fluids or materials deposit on the articles and
provide
CA 02238122 1998-06-23
r . . _23_
nutrition for the proliferation of microbes. In addition, many plasticizers
which are
often used to increase flexibility in the final plastic article or to
facilitate processing
are readily digestible by microbes (see below).
A greater source of nutrition in plastic-based mastication articles for pets
relates to the methods by which the articles are made desirable to pets.
Plastics are
generally not particularly attractive to pets, especially those plastics which
possess
good natural microbe-starving characteristics. For this reason, others have
incorporated elements into such plastic-based mastication articles to make
them more
attractive for pets, and these elements include animal meal, sugar, and
others.
Because these elements are also digestible by microbes, however, the natural
microbe
starving characteristics which the articles may have possessed can become
ineffectual.
The present invention allows for plastic-based mastication articles to be
constructed whereby the articles possess effective protection against the
proliferation
of microbes, even when digestible elements intended to make the articles more
attractive for pets have been incorporated into the articles.
Plastic mastication articles for pets are frequently made by molding (e.g.,
injection molding, blow molding), or dipping processes known in the plastics
fabrication art. One typically starts with the plastics in resin or latex
form.
Preferred plastic materials for the present invention, alone or in
combination,
are nylon and polyurethane, although many other types of plastics, e.g.,
polyolefins,
are suitable as well. It is generally preferred to us thermoplastics.
The preferred microbe-inhibiting agent for direct incorporation into the
plastic
material is 2,4,4'-trichloro-2'-hydroxydiphenol (e.g., microban). For
thermoplastics
processing, the agent is preferably contained in a resin fraction which is
compatible
with the base material being used to fabricate the article. It is preferred
that the resin
fraction be of the same base material being used to fabricate the article.
The microbe-inhibiting resin fraction is added to the base material resin in
an
amount such that the concentration of the agent in the final product is
between
0.001 % and 1.5%, preferably between 0.004% and 0.7%. The resin mix is then
well
blended to ensure homogeneity.
CA 02238122 1998-06-23
-24-
For injection molded products, the resin mix is poured into the hopper of the
injection molding machine. The blend is forced into a heating region and
ultimately
extruded into the appropriate mold shapes.
Another preferred agent is Ultra Fresh DM-50. It is added such that its
concentration in the final article is between 0.001 % and 1 %, preferably
between
0.05% and 0.6%.
In latex processing, the microbe-inhibiting agent in powder or liquid form or
suitably incorporated into a solid or liquid carrier is preferably added to
the latex
mixture before molding. Preferred microbe-inhibiting agents are triclosan,
Ultra
Fresh DM-50, and chlorine dioxide.
2,4,4'-trichloro-2'-hydroxydiphenol can also be obtained in a crystalline
powder form (e.g., from TRInternational, Inc.), and the powder can be added to
the
plastics formulation process. For example, the powder can be added directly to
the
latex mixture. It can also be incorporated directly into the molten form of
many
thermoplastics. In the latter case, however, one must be especially careful to
ensure
homogeneity by appropriate mixing methods.
Other desirable ingredients may be added to the plastic-based mastication
articles to impart a desirable flavor or scent. For example meat broths,
ground-up
dried meat products, etc. The use of such ingredients has been described in
the art.
The addition of such ingredients can, however, negate the natural microbe-
starving
quality of these base polymer materials. Unfortunately, ingredients which are
likely
to make the make the article more attractive to pets are generally of a
digestible nature
(meat-based products, sugars, etc), and are therefore likely to provide
nutrition for the
proliferation of microbes. This fundamental trade-off is circumvented by the
present
invention. In constructing plastics-based mastication articles with such
flavoring
ingredients, one can include a preferred microbe-inhibiting agent in the resin
mix or
the precursor solution of the base plastic material; the preferred
concentrations and
related considerations given above apply.
A preferred means for constructing plastics-based mastication articles with
such flavoring ingredients to pre-treat the flovoring ingredients themselves
with
CA 02238122 1998-06-23
-25-
microbe-inhibiting agents (which may be done alone or in combination with
providing
the base plastic material with microbe-inhibiting properties).
If one is incorporating a solid or solid-like flavoring ingredient into a
resin or
melt mixture, it is preferred to soak the flavoring ingredients in a solution
containing
one or more microbe-inhibiting agent before incorporating the ingredients
intro the
resin or melt mixture. The ingredients should be dried before incorporation
into the
resin or melt mixture.
A preferred agent for use in treating the flavoring ingredients is chlorine
dioxide, which is safe for both animal and human consumption. An appropriate
solution concentration is in the range of about 0.1-2%.
Also preferred is Ultrafresh DM-50. Water is the primary solvent for the
preferred treatment solution, which contains between 0.005%-0.4%, preferably
0.008%-0.1% of the DM-50 agent.
Also preferred is triclosan. The treatment solution has a concentration
between 0.01% and 1.2%, preferably between 0.05% and 0.6%. An alcohol,
preferably ethanol, is the primary solvent of the preferred treatment
solution. When
treating by soaking in a triclosan solution, subsequent rinsing in an aqueous
solution
is preferred.
If one is incorporating a flavoring agent by soaking the article in a solution
containing that agent (and possibly at elevated temperature and/or pressure),
it is
preferred to incorporate a preferred microbe-inhibiting agent in the treatment
solution.
A preferred agent in this case is chlorine dioxide (in the range of about 0.1-
2%).
Also preferred is Ultrafresh DM-50 (preferably with water as a primary
solvent, and in concentrations between 0.005%-0.4%, preferably 0.008%-0.1 %).
Also preferred is triclosan, preferably with ethanol as the primary solvent,
and
in concentrations between 0.01 % and 1.2%, preferably between 0.05% and 0.6%.
The microbe-starving quality of some synthetic polymers is often
unintentionally destroyed by processing with a plasticizer which contains
nutritive
elements which can support microbial proliferation. The plasticizers used in
processing many polymers axe digestible and/or degradable by microbes. If a
CA 02238122 1998-06-23
. . ~ . . _26_
plasticizer is to be used in processing materials used for constructing a
mastication
article for a pet, it is preferred to choose a plasticizer which does not
diminish the
natural microbe-starving and/or microbe-impenetrable property of the polymer.
Plasticizers which are particularly resistant to fungal growth include:
Abietic acid;
hydrog. methyl abietate; tri-n-butyl aconitate; triethyl aconitate; di-(2-
ethylhexyl)adipate; di-(2-ethylhexyl)acetate; ethyl-o-benzyl benzoate;
chlorinated
diphenyls; chlorinated paraffins; tri-n-butyl citrate; triethyl citrate; 2-
nitro-2 methyl-
1,3-propanediol diacetate; dimethyl phthalate; di-n-propyl phthalate;
diisopropyl
phthalate; dibutyl phthalate; diisobutyl phthalate; diisodecyl phthalate;
dihexyl
phthalate; dicapryl phthalate; di-(2 ethylhexel) phthalate; di-(2 ethylhexyl)
phthalate;
dicyclohexyl phthalate; dicyclohexyl phthalate; and dibenzyl phthalate.
Other Types of Plastic Articles
Plastics articles to be used for purposes other than as mastication articles
for
pets may be made under the purview of the present invention. Particularly
desirable
are feeding bowls. Injection molded thermoplastic bowls, made, e.g., of
polymers
such as polypropylene and polyethelene, fabricated by incorporating a resin
fraction
of Microban-containing resin, are preferred. The Microban agent should be
incorporated into the bowl at a concentration between 0.0005% and 0.1.2 %,
preferably between 0.001 % and 0.8%. Combs and other grooming aids can be
manufactured in a similar manner.
In support of the present invention, the following experiments were conducted:
Example 1
A treatment bath was prepared as follows: A chlorine dioxide starting solution
comprising 2% chlorine dioxide and 0.085% sodium carbonate was obtained (from
3R
Marketing Associates). 100 ml of this solution was mixed with 400m1 of water.
The
solution was heated to 90C. Four grams of agar was then added to this
solution.
Rawhide was acquired commercially in strip form. A strip with dimensions
approximately 6cm x 6cm, and about 1.6mm thick was cut using a knife.
The rawhide strip was placed in the treatment bath, which was then covered.
The strip was treated in the bath, with occasional stirring, for 2 hours.
CA 02238122 1998-06-23
. , t . . _27_
The strip was removed from the bath and allowed to air dry.
Example 2
A first treatment bath is prepared using 800 ml of water as the treatment
solution.
A second treatment bath was prepared as follows: A mixture of 1 gm of
triclosan crystalline powder (obtained from TRInternational, Inc.) was mixed
with
200m1 of grain alcohol (95% ethanol by volume); and the mixture was stirred.
A third treatment bath is prepared using 800 ml of water maintained at 80C.
Rawhide was acquired commercially in strip form. A strip with dimensions
approximately 6cm x 6cm, and about 1.6mm thick was cut using a knife.
The rawhide strip was placed in the first treatment bath, which was then
covered. The bath with the strip was allowed to sit at room temperature for
eight
hours
The rawhide strip was then removed from the first treatment bath and placed
into the second treatment bath, which was then covered. The bath with the
strip was
maintained, with occasional stirring, at room temperature for four hours.
The rawhide strip was then removed from the second treatment bath and
placed into the third treatment bath, which was then covered. The third
treatment bath
with the strip was allowed to sit at 80C for four hours.
The strip was removed from the bath and allowed to air dry.
_Example 3
A first treatment bath is prepared using 800m1 of a 0.9% saline solution (0.9%
Sodium Chloride Irrigation, USP, from Baxter Healthcare Corporation).
A second treatment bath was prepared as follows: A mixture of 0.3gm of
triclosan crystalline powder (obtained from TRInternational, Inc.) was mixed
with
200m1 of grain alcohol (95% ethanol by volume); and the mixture was stirred.
Rawhide was acquired commercially in strip form. A strip with dimensions
approximately 6cm x 6cm, and about 1.6mm thick was cut using a knife.
The rawhide strip was placed in the first treatment bath, which was then
covered. The bath with the strip was allowed to sit at room temperature for
six hours
CA 02238122 1998-06-23
r , . _28_
The rawhide strip was then removed from the first treatment bath and rinsed
with water. It was then placed into the second treatment bath, which was then
covered. The bath with the strip was allowed to sit at room temperature for
three
hours.
The strip was removed from the bath, rinsed generously with water, and
allowed to air dry.
Example 4
A treatment bath was prepared as follows: A mixture of 0.7 gm of triclosan
crystalline powder (obtained from TRInternational, Inc.) was mixed with 100m1
of
grain alcohol (95% ethanol by volume); and the mixture was stirred. 100 ml of
water
was added to the mixture, causing the solution to take on a white, milky
appearance.
Rawhide was acquired commercially in strip form. A strip with dimensions
approximately 6cm x 6cm, and about 1.6mm thick was cut using a knife.
The rawhide strip was placed in the treatment bath, which was then covered.
The bath with the strip was allowed to sit at room temperature for eight
hours.
The strip was removed from the bath and allowed to air dry.
Example 5
A first treatment bath is prepared by adding two ounces of sugar to 800 ml of
water, and stirring and heating until the sugar dissolves. The bath is then
placed on a
hotplate and maintained at 60C.
A second treatment bath was prepared as follows: A solution of 0.3% Ultra
Fresh DM-50 in water (Thomas Research Associates) is covered and heated at
35C.
Rawhide was acquired commercially in strip form. A strip with dimensions
approximately 6cm x 6cm, and about 1.6mm thick was cut using a knife.
The rawhide strip was placed in the first treatment bath, which was then
covered. The bath with the strip was allowed to sit at 60C for 3 hours.
The rawhide strip was removed from the first treatment bath, rinsed
generously, and placed into the second treatment bath, which was then covered.
The
bath with the strip was allowed to sit at 35C for four hours.
The strip was removed from the bath and dried in an oven for 1 hour at 85C.
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Example 6
An 8" length piece is cut from a roll of cotton rope. An aqueous treatment
solution
is prepared containing 0.2% Ultra Fresh DM-50 (Thomas Research Associates).
The
solution is kept covered and maintained at room temperature. The cut rope is
rope is
placed into the treatment solution, weighted down with a U-shaped piece of
glass.
The rope piece is periodically agitated in the treatment solution. After 2
hours, the
rope is removed from the treatment solution and dried in a vacuum oven at 60C.
Example 7
An 10" length piece is cut from a roll of cotton rope. A treatment solution is
prepared comprising an ethanol solvent with 0.2% triclosan (obtained from
TRInternational, Inc.) and 1 % butyl cellulose. The solution is heated to 40C
and kept
covered. The cut rope is rope is placed into the treatment solution and is
periodically
agitated. After 1.2 hours, the rope is removed from the treatment solution and
hung
from a clothes line for 40 minutes. The rope is then dried in a vacuum oven at
80C.
Example 8
An 8" length piece is cut from a roll of cotton rope. A knot is tied at either
end
to give the rope the appearance roughly of a bone. An aqueous treatment
solution is
prepared as follows: 300m1 of a chlorine dioxide starting solution comprising
2%
chlorine dioxide and 0.085% sodium carbonate (from 3R Marketing Associates)
was
mixed with 700m1 of water. The solution is maintained at 80C. 20gm of beef
flavor
bouillon (Herbox, from Hormel Foods) is added to the solution, which is
stirred until
the bouillon is dissolved. The solution is kept covered and maintained at 80C.
The
cut rope is rope is placed into the treatment solution and weighted down with
a U-
shaped piece of glass. The rope piece is periodically agitated in the
treatment
solution. After 2 hours, the rope is removed from the treatment solution and
dried in a
vacuum oven at 60C.
Example 9
An 8" length piece is cut from a roll of cotton rope. A knot is tied at either
end
to give the rope the appearance roughly of a bone. An aqueous treatment
solution is
prepared as follows: 300m1 of a chlorine dioxide starting solution comprising
2%
CA 02238122 1998-06-23
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chlorine dioxide and 0.085% sodium carbonate (from 3R Marketing Associates) is
mixed with 700m1 of water. The solution is heated to and maintained at 95C. l
Ogm
of agar is stirred into the solution. The cut rope is rope is placed into the
treatment
solution and weighted down with a U-shaped piece of glass. The rope piece is
periodically agitated in the treatment solution. After 2 hours, the rope is
removed
from the treatment solution and dried in a vacuum oven at 60C.
