CA2238122A1 - Mastication articles possessing microbe-inhibiting properties - Google Patents

Abstract

A mastication article for a domestic animal comprising tough chew-resistant material defining a shape in the forth of a small article for enticing or being retrieved by a domestic animal, and an effective amount of microbe-inhibiting agent applied to or incorporated in the material. The mastication articles may be fabricated in various shapes, designs, and styles. A process for applying the microbe-inhibiting agent to the material for forming the mastication article is provided. Application methods include spraying and soaking the article, and incorporating the agent within a resin for molding the article.

Description

_1_ 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 ' , ' ~ ~ _2_ 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 w ~ ' _3_ 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 -4_ 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 ni ~ J n 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 _6_ 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.

~ ~ , a ' _7_ 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;

' ' _g_ 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 .. r~
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 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 '' " ' " -11-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.

' -12-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 ' -13-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.

,, . , , ~ -14-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 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).

,., ~, , _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 .,, 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).

. . . ~ . ' -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 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%.

' ' -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 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 . , , 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 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 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.

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 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 . . ~ . . _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 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.

. , 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 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.

r , . _29_ 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%

r , . _30_ 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.

Claims (72)

1. A mastication article constructed for mastication by a domestic animal comprising:
a tough chew-resistant material defining a shape in the form of a small article for enticing or being retrieved by a domestic animal;
the chew-resistant material having an effective amount of a microbe-inhibiting agent.

2. A mastication article according to claim 1 wherein the material is made from a group consisting of animal skin, animal fat, vegetable, or some blend thereof.

3. A mastication article according to claim 1 wherein the material is selected from a group consisting of polymeric resins or solutions, fibers or threads, textile materials, foams, or some blend thereof.

4. A mastication article according to claim 1 wherein the microbe-inhibiting agent is 2,4,4'-trichloro-2'-hydroxydiphenol.

5. A mastication article according to claim 1 wherein the microbe-inhibiting agent is tri-n-butylin maleate.

6. A mastication article according to claim 1 wherein the microbe-inhibiting agent is chlorine dioxide.

7. A mastication article according to claim 1 wherein the microbe-inhibiting agent is 3-trimethoxysilylpropyldimethyloctadecyl ammonium chloride.

8. A mastication article according to claim 1 wherein the microbe-inhibiting agent is a complex of polysubstituted imine salts and trialkyl phosphate esters with free alkylated phosphoric acid.

9. A mastication article according to claim 1 wherein the microbe-inhibiting agent is a particulate incorporated into the material and comprising core particles over which is coated a microbe-inhibiting active layer.

10. A mastication article according to claim 9 wherein the core particles are selected from a group comprising zinc oxide, titanium oxide, barium sulfate, or a blend thereof.

11. A mastication article according to claim 9 wherein the active layer is selected from a group comprising silver, copper oxide, zinc silicate, or a blend thereof.

12. A mastication article according to claim 11 wherein the active layer further includes a barrier coating, whereby the rate of release of the microbe-inhibiting agent can be controlled.

13. A mastication article according to claim 11 wherein the active layer further includes a dispersion coating, whereby the core particles in the material are dispersed.

14. A mastication article according to claim 1 wherein the tough chew-resistant material is digestable.

15. A mastication article according to claim 14 wherein the digestable material is rawhide.

16. A mastication article according to claim 14 wherein the digestable material selected from a group consisting of animal skin, animal fat, vegetable, or some blend thereof.

17. A mastication article according to claim 1 wherein the tough chew-resistant material includes rope.

18. A mastication article according to claim 17 wherein the rope comprises a material selected from a group including cotton, sisal, hemp, jute, henequen, or a blend thereof.

19. A mastication article according to claim 18 wherein the microbe-inhibiting agent is tri-n-butylin maleate.

20. A mastication article according to claim 19 wherein the tri-n-butylin maleate is present from 0.03 to 1.2 percent by weight of the mastication article.

21. A mastication article according to claim 18 wherein the the tri-n-butylin maleate is 3-trimethoxysilylpropyldimethyloctadecyl ammonium chloride.

22. A mastication article according to claim 21 wherein the 3-trimethoxysilylpropyldimethyloctadecyl ammonium chloride is present from 0.08 to 0.15 percent by weight of the mastication article.

23. A mastication article according to claim 18 wherein the microbe-inhibiting agent is chlorine dioxide.

24. A mastication article according to claim 23 wherein the chlorine dioxide is present from 0.01 to 1.2 percent by weight of the mastication article.

25. A mastication article according to claim 18 wherein the microbe-inhibiting agent is 2,4,4'-trichloro-2'-hydroxydiphenol.

26. A mastication article according to claim 17 wherein the rope comprises a material selected from a group including nylon, acrylics, polyester, polypropylene, or a blend thereof.

27. A mastication article according to claim 26 wherein the microbe-inhibiting agent is 2,4,4'-trichloro-2'-hydroxydiphenol.

28. A mastication article according to claim 27 wherein the 2,4,4'-trichloro-2'-hydroxydiphenol is present from 0.01 to 1.8 percent by weight of the mastication article.

29. A mastication article according to claim 1 wherein the material is selected from a group including nylon, polyurethane, polyolefins, or a blend thereof.

30. A mastication article according to claim 29 wherein the microbe-inhibiting agent is 2,4,4'-trichloro-2'-hydroxydiphenol.

31. A mastication article according to claim 30 wherein the 2,4,4'-trichloro-2'-hydroxydiphenol is present from 0.001 to 1.5 percent by weight of the mastication article.

32. A mastication article according to claim 29 wherein the microbe-inhibiting agent is tri-n-butylin maleate.

33. A mastication article according to claim 32 wherein the tri-n-butylin maleate is present from 0.001 to 1 percent by weight of the mastication article.

34. A mastication article according to claim 29 wherein the microbe-inhibiting agent is chlorine dioxide.

35. A mastication article according to claim 29 wherein the material includes a nutritive attracting agent.

36. A mastication article according to claim 35 wherein the nutritive attracting agent is selected from a group including animal meal, meat broth, dried meat, sugar, or a blend thereof.

37. A mastication article according to claim 35 wherein the microbe-inhibiting agent or property is chlorine dioxide.

38. A plastic article for a domestic animal wherein the article being formed by molding a synthetic resin into a geometric shape;
the synthetic resin having an effective amount of a microbe-inhibiting agent incorporated therein.

39. A plastic article according to claim 38 wherein the material is non-digestable and selected from a group consisting of polymeric resins or solutions, fibers or threads, textile materials, foams, or some blend thereof.

40. A plastic article according to claim 38 wherein the microbe-inhibiting agent or property is 2,4,4'-trichloro-2'-hydroxydiphenol.

41. A mastication article according to claim 38 wherein the microbe-inhibiting agent or property is tri-n-butylin maleate.

42. A plastic article according to claim 38 wherein the microbe-inhibiting agent or property is chlorine dioxide.

43. A plastic article according to claim 38 wherein the microbe-inhibiting agent or property is 3-trimethoxysilylpropyldimethyloctadecyl ammonium chloride.

44. A plastic article according to claim 38 wherein the microbe-inhibiting agent or property is a complex of polysubstituted imine salts and trialkyl phosphate esters with free alkylated phosphoric acid.

45. A plastic article according to claim 38 wherein the microbe-inhibiting agent or property is a particulate incorporated into the material and comprising core particles over which is coated a microbe-inhibiting active layer.

46. A plastic article according to claim 45 wherein the core particles are selected from a group comprising zinc oxide, titanium oxide, barium sulfate, or a blend thereof.

47. A plastic article according to claim 46 wherein the active layer is selected from a group comprising silver, copper oxide, zinc silicate, or a blend thereof.

48. A plastic article according to claim 47 wherein the active layer further includes a barrier coating, whereby the rate of release of the microbe-inhibiting agent or property can be controlled.

49. A plastic article according to claim 47 wherein the active layer further includes a dispersion coating, whereby the core particles are dispersed in the material.

50. A plastic article according to claim 38 wherein the geometric shape is a bowl for containing pet food or drink.

51. A plastic article according to claim 50 wherein the material is a polymer and the microbe-inhibiting agent is 2,4,4'-trichloro-2'-hydroxydiphenol.

52. A plastic article according to claim 51 wherein the microbe-inhibiting agent or property is present from 0.0005 to 1.2 percent by weight of the plastic article.

53. A process for imparting microbe-inhibiting properties to 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, including the step of applying to or incorporating in the material an effective amount of a microbe-inhibiting agent.

54. A process according to claim 53 wherein the microbe-inhibiting agent is chlorine dioxide.

55. A process according to claim 53 wherein the microbe-inhibiting agent is 2,4,4'-trichloro-2'-hydroxydiphenol.

56. A process according to claim 53 wherein the microbe-inhibiting agent is tri-n-butylin maleate.

57. A process according to claim 53 wherein the application step includes applying or incorporating a solution including the microbe-inhibiting agent to the mastication article.

58. A process according to claim 57 wherein the application step includes soaking the mastication article in the solution including the microbe-inhibiting agent.

59. A process according to claim 57 wherein the application step includes spraying the mastication article with the solution including the microbe-inhibiting agent.

60. A process according to claim 53 wherein the application step includes 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.

61. A process according to claim 60 wherein the application step includes incorporating the particles into a dope before fiber spinning the mastication article.

62. A process according to claim 53 wherein the application step includes incorporating the particles into a spray for coating the mastication article.

63. A process according to claim 53 wherein the application step includes applying or incorporating the microbe-inhibiting agent to the material during cleaning, wherein the material is rawhide.

64. A process according to claim 53 wherein the application step includes applying or incorporating the microbe-inhibiting agent to the material during liming, wherein the material is rawhide.

65. A process according to claim 53 wherein the solution includes an attracting agent which will impart a flavor or a smell to the mastication article.

66. A process according to claim 53 wherein the application step includes applying the microbe-inhibiting agent at a temperature between 40 and 100 degrees Celsius.

67. A process according to claim 53 wherein the application step includes applying moisture to the material as it is being formed, and then spraying the material with a solution including the microbe-inhibiting agent, wherein the material includes cotton rope.

68. A process according to claim 53 wherein the material includes fibers and the applying or incorporating step includes adding the microbe-inhibiting agent to a dope for spinning a portion of the fibers.

69. A process according to claim 53 wherein the step of incorporating a microbe-inhibiting agent includes adding a resin having a microbe-inhibiting agent to the material before molding the mastication article.

70. A process according to claim 69 wherein the resin includes an attracting agent which will impart a flavor or a smell to the mastication article.

71. A process according to claim 53 wherein the step of incorporating a microbe-inhibiting agent includes adding the microbe-inhibiting agent to a latex mixture, which is then molded to form the article.

72. A process according to claim 69 wherein the resin includes an attracting agent which will impart a flavor or a smell to the mastication article.