CA2688496A1 - Non-dusting, odor control and clumping sodium bentonite/calcium carbonate-based cost effective animal litter - Google Patents

Description

NON-DUSTING, ODOR CONTROL AND CLUMPING SODIUM BENTONITE/CALCIUM
CARBONATE-BASED COST EFFECTIVE ANIMAL LITTER
FIELD OF THE INVENTION
The disclosure of this invention generally relates to a dust and odor control particular materiai and a process for making the same. The disclosure more particularly relates to disposable cat litter and a method of making the same. In one embodiment, this invention is directed to a process (FIG. 6) and a cat litter composition formed primarily from sodium bentonite and calcium carbonate in particulate form where the blend particles are treated, e.g. surface treated, first with preferably vegetable or synthetic oil and secondly with an inhibiting odor agent based on polyborate and a method of making the same. After treatment, the cost effective cat litter is dust-free and furthermore has significantly increased odor control properties.
BACKGROUND
Animal litters Animal and pet litters, such as cat litters, are typically mixtures of absorbent materials, odor controlling agents, clumping agents, and other functional or cosmetic enhancing additives. Absorbent materials cover a wide range of materials and can include recycled newsprint, paper sludge, corn cob granules, rice hulls, peanut hulls, alfalfa, cedar sawdust, and various clays such as calcium and sodium montmorillonites (including sodium bentonite), attapulgites, kaolins, and opal clay mixtures. Currently, clay-based litters which provide a clumping property allowing removal of liquid waste from the litter container without excessively contaminating the remaining litter have become popular.
Clumps are created when the composition of the swells during the absorption of pet urine, creating a localized rigid clump. Typical additives for litter which provide this swelling and urine absorption property include montmorillonite clays.
Clay particles have long been used for providing small animals with dry, sanitary, dustless and relatively odorless litter and bedding. The clay-based litters are now widely used. However, the quality of the cat litters on the market wopuld benefit from improvement; they are often dusty, develop urine odors and attach to the animal's fur or paw and will be tracked throughout the house. The dry clay in the house may become a source of dust that may carry microorganisms and/or cause allergic reactions.
Also, when the animal licks its paws, the clay will be ingested by the animal and may cause the animal health problems.
The animal litter nevertheless is dusty during manufacture, as well as dispensing.
What is needed is a relatively dust-free clumping animal litter that can be periodically disposed. Also needed is a cat or animal litter composition that retards the formation of odiferous substances and eliminates the malaise odor of common litter boxes.
Odor control is generally achieved by adding ingredients to the litter that either mask the odor or add compounds that are anti-bacterial, or other compounds that exhibit pleasant smell. The uririe odor is created by the formation of amine containing compounds produced by decomposition of urine and by urine decomposing gram-positive bacteria.
Many approaches have been tried to produce a litter that is humane and animal safe and acceptable.
U.S. Pat. No. 5,329,880 to Pattengill, et al. discloses clumpable animal litter. This waterproof litter contains a mixture of non-smectitic, hydrophilic shale aggregate with a fraction of coarse material with a size less than about 5 mesh (4000 microns).
The

2 mixture has the property of agglomerating into a clump upon contact with urine. The agglomerated clump of shale and urine is removable with a perforated scoop.
The shale may contain up to 10 weight percent clumping agent selected from the group of water absorbent polymers, corn starch, gelatin, gluten and dried plants of the Plantago family.
In addition 5 to 25 wt % ammonia absorbing zeolite may be added for odor control. The odor control agent is an absorbent for ammonia and does not provide odor control since ammonia is not immediately formed.
U.S, Pat. No. 5,806,462 to Parr discloses clumping animal litter. The animal litter is particularly for cats and has a gelatin solution and a dry adhesive sprayed onto the granules. The gelatin solution provides enough dampening to adhere the adhesive particles to the clay particles. Because the gelatin sets quickly, it does not provide so much wetting as to activate the adhesive. Therefore, the adhesive retains its adhesive properties ancl, together with the gelatin, causes the litter to clump when wetted by an animal. This clumping cat litter formulation provides no odor control.
U.S. Pat. No. 3,675,625 to Miller et al. teaches a litter which is "activated"
by heating and then contacted with an odor control agent, such as pine oil, citrus oil, camphor or the like.
U.S. Pat. No. 4,129,094 to Stockel discloses the use of fly ash, bottom ash and/or boiler slag as cat litter materials. The composition of fly ash, as determined by the ASTM
includes silicon dioxide, alumina, ferric oxide, calcium oxide, magnesium oxide, sodium oxide and potassium oxide. This is a complex chemically reacted composition and absorbs urine but does not eliminate the odor.
U.S. Pat. No. 4,203,388 to Cortigene et al. teaches the use of a deodorant such as sodium bicarbonate, in amounts of between about 1% and about 10% of the dry weight of the litter. Such large amounts of deodorizer are necessitated since the litter itself is also used as an absorbent for urine, requiring the deodorizer to be homogeneously dispersed throughout the particles of the litter.
U.S. Pat. No. 4,405,354 to Thomas et al. discloses the use of buffering agents to prevent gaseous ammonia from escaping into the air. However, such buffering agents serve only to prevent the formation of gaseous ammonia; they are ineffective against other unpleasant odors. Further, the amounts of such agents range from about 0.5% to about 25% by weight, since all of the absorbent litter must be treated with the agent to provide sufficient contact with the urine.
U.S. Pat. No. 4,494,482 to Arnold discloses an animal litter composition. This solid absorbent material has about 25 ppm to about 500 ppm of a halogenated aromatic hydrocarbon bacteriostat that effectively prevents the development of urine odors. The bacteriostat is selected from the group consisting of p-chloro-m-cresol;
hexachlorophane, 2,4,4'-trichloro-2'-hydroxydiphenyi ether, trichlorocarbanilide, 2,4-dichloro-m-xylenol, 3,4,5-tribromosalicylanilide, 3,5,3',4'-tetrachlorosalicylanilide or

3,5,3',5'-tetrachlorodiphenyl sulfide. These chlorinated or brominated compounds kill odor-producing bacteria.
U.S. Pat. No. 5,097,799 discloses odor control agents selected from the group consisting of guanidine salts, alkali metal fluorides, alkali metal bisulfites, and mixtures thereof.
These agents are applied to the litter using an aqueous dispersion to produce an odor control animal litter.
U.S. Pat. No. 5,634,431 to Reddy, et al. discloses odor inhibiting pet litter.
The addition of urease negative bacteria to sodium srnectite clay minerals in pet litter inhibits growth of urease positive bacteria for a period of several days, thereby retarding formation of ammonia and other obnoxious odors. Approximately fifty percent sodium bentonite in the litter causes the litter to clump upon wetting, maintaining the urea in contact with the treated clay and also serving as a buffer to favor growth of the urease negative bacteria.
This composition entirely relies on inhibiting ammonia formation and does not provide immediately a pleasant scent.
U.S. Pat. No. 5,975,019 to Goss, et al. discloses clumping animal litter. The clumping animal litter utilizes tiie interparticle interaction of sodium bentonite swelling clay with a non-swelling clay material. Preferably, sixty percent (60%) by weight, or less, composition of sodium bentonite is used after the judicious selection of particle size distribution such that the mean particle size of the non-swelling clay material is greater than the mean particle size of the sodium bentonite. In addition, an organic clumping agent, such as a pregelatinized corn starch can be combined with the sodium bentonite/clay mixture to enhance clumping properties. This clumping clay litter does not control odor.
U.S. Pat. No. 6,015,550 to Marquis discloses a method for controlling odor using alkylene carbonates. These alkylene carbonates are useful for reducing odor where an odoriferous amine-containing compound is present under conditions such that the alkylene carbonate forms a reaction product with odoriferous amine-containing compounds reducing the odor. Sources of such amine-containing compounds include chicken coops, dumps, landfills, cat litter, stagnant water, water treatment ponds and plants, garbage cans and dumpsters, dog kennels, zoos, rendering plants food processing plants, slaughter houses, wool plants, fish canneries (cleaning and processing plants), underground sewers, paper mills, paper processing, outhouses and toilets that have no running water, and public restrooms. The alkylene carbonate is ethylene carbonate, propylene carbonate, butylene carbonate. Propylene carbonate is a liquid at room temperature and has to be sprayed. Ethylene carbonate is a solid at room temperature and does not immediately react with the odor molecules. Therefore, it is unsuited for incorporation in a cat litter.
U.S. Pat. No. 6,206,947 to Evans, et al. discloses a process for making an animal litter comprising gypsum, aluminum sulfate and urea. The animal litter composition is an agglomerated or compacted calcined calcium sulfate absorbent. The animal litter composition is screened to a particle size between 6 mesh and about 100 mesh and an effective amount of a binder such as a clay, lignin or starch is added to the calcium sulfate to assist the calcium sulfate to pelletize. This is a gypsum composition that is agglomerated using aluminum sulfate and urea to chemically combine with gypsum.
There is no odor control in this clumping litter composition.
U.S. Pat. No. 6,253,710 to Ward, et al. discloses odor control for animal litter. It uses an odor control liquid and an aerosolized coniposition for deodorizing and controlling the odor of animal wastes. The liquid and aerosolized composition comprises a non-aqueous volatile carrier and an odor control agent. The liquid and aerosolized composition can be applied in liquid form directly to the animal litter and/or the animal container and/or the animal waste. The litter container may be sprayed with a powdered release agent which may be talc, inorganic silicone and magnesium powders, sodium bicarbonate, chlorophyll, sodium dihydrogen phosphate, potassium acid phthalates, or their mixtures preventing the stickiness of the odor controlling liquid. The liquid mixes with the litter product and always evaporating disseminates the odor control agent and is quickly exhausted.

4 U.S. Pat. Nos. 6,667,030 and 6,743,420 to Schneider disclose odor control composition and process. The odor control composition eliminates household, institutional and industrial odors including cat urine odor. The odor control composition is a solution of Chloramine-T which may incorporate a suitable wetting agent. Chloramine-T
describes a variety of compounds which are based on N-Sodium, N-chloro-para-toluenesulfonamide and N-Sodium, and N-Chloro-Para-Benzene sulfonamide. This chlorine-containing compound is highly reactive and is unsuitable for use in a cat litter.
U.S. Pat. No. 6,702,951 to Shultz discloses scent adsorbing liquid formulation. This odor-absorbing liquid formulation comprises a preservative an alkali metal salt, and a particulate odor-adsorbing agent such as activated carbon. The fqrmulation may further include an alkylaryl polyether nonionic surfactant and may lrave an alkaline pH. The liquid formulation is applied to apparel to be worn during hunting or observation to avoid being sensed by animals and is not included in cat litter. The alkaline pH may be advantageous in promoting penetration or coverage of the substance being treated, in retarding formation of some odiferous substances, and in providing an environment in which the anti-microbial preservatives are most effective in inhibiting bacterial growth and development.
U.S. Pat. No. US 20030072733 discloses a free flowing, fragranced, moisture absorbing, composition of an enrobement material such as clays, silicas, celites, zeolites, metal salts, celluloses, starches, carbonates, borates, sulfates, water soluble polymers, borax, and mixtures thereof, a fragrance, an absorbent material, and a fixative.
Borate, boric acid and polyborates Boric acid and sodium tetraborate have been used for years as an insecticide, fungicide, herbicide, and bacteriocide, but are virtually non-toxic to humans, animals, birds, fish, aquatic invertebrates, beneficial insects and have a low impact on the environment. The LD50 toxicity of borax is about the same as table salt (e.g. 3,000 mg/kg body weight).
Boron, as found in boric acid and sodium tetraborate, is an effective specific inhibitor of bacterial urease and hydrogenase. One of the key reactions involved in the release of ammonia from urine in cat litter is the hydrolysis of urea by the bacterial enzyme, urease.
Many enteric bacteria possess urease activity, including pathogens such as Escherichia coli, Actinobacillus pleuropneumoniae, Salmonella, Klebsiella, Clostridium, Streptococcus and Staphylococcus.
Boric acid and sodium tetraborate were evaluated for their ability to inhibit ammonia and hydrogen sulfide emissions from swine wastewater and manure slurry in in-vitro incubations. Addition of either 1% boric acid or sodium tetraborate inhibited ammonia and hydrogen sulfide emissions by almost 100 % froni wastewater and manure slurries over 7 days of incubation. Concentrations of boric acid and sodium tetraborate as low as 0.0625 %, were effective in treating wastewater. Other possible benefits for using boron include a reduction in malodor of the manure slurry, control of enteric pathogens and inhibition of mold growth.
Products based on borax are thought to involve the borate inhibition of the urease enzyme, preventing ammonia formation. Isao Tsuyumoto et al. in Inorganic Chemistry Communications 10 (2007) 20-22, reported that borates are used extensively in treating wood to protect against decay by brown and white rot, and staining by fungi. Insecticidal use of borates is attractive because of their low mammalian toxicity and lack of insect resistance compared with the organic insecticides.
The literature contains over 150 references in this field. Species showing promise for control by borate-based insecticides are the powder post beetle (Lyctus brunneus) in hardwoods and larvae of several other beetles which attack soft wood. Some species of subterranean termites like Coptotermes and Reticulitermes which contain gut protozoa are susceptible, because boron is toxic to these cellulose-digesting organisms and leads

5 to starvation of the host as well as systemic effects. Less research has been done on drywood termites, but some success has been obtained with Cryptotermes.
Sodiuni octaborate, a highly soluble polyborate, is of interest both for pre and posttreatment of wood.
U.S. Pat. No. 5,183,655 teaches an odor control animal litter that has applied to it an effective amount of pine oil in combination with an effective amount of boric acid.
U.S. Pat. No. 5,992,351 to Jenkins discloses clumpable animal litter with improved odor control. The clumpable animal litter with improved odor control comprises a) water-swellable clay particles capable of adhering other such particles upon contact with moisture; and b) an odor controlling-effective amount of a boron compound of a composition di-alkali metal tetraborate n-hydrate, wherein n is 4, 5 or 10, which controls odors arising from the contact of said clay particles with moisture.
U.S. Pat. No. 4,949,672, Jenkins; Dennis B. et al. teaches an odor control animal litter comprising particles of an absorbent clay substrate. The particles have being contacted with a liquid carrier containing an odor-controlling-effective amount of a mixture of boric acid and borax having an equivalent boron level of at least 0.06% and said liquid carrier comprising an alkali metal hydroxide in solution.
Still further, it has been suggested in U.S. Pat. No. 4,263,873 to Christianson, that a borax/boric acid mixture at a pH of 4-4.5 could be added to a cellulose litter containing a pheromone. Yet further, in U.S. Pat. No. 5,094,190 to Ratcliff et al. teaches an odor control animal litter to which a boron-containing liquid material has been applied. Ratcliff et al. has claimed a clay-based, particulate substrate to which has been applied a liquid carrier containing a boron-containing material at a critical level of at least 0.06%
equivalent boron.
This reference has several deficiencies in that when borax and boric acid are mixed together with sodium hydroxide in solution before spraying the cat litter yielded metaborate tetrahydrate as precipitating product which blocks the nozzles of spraying machine and decrease the concentration of borate needed to react with odor generating material. When we prepare a saturated solution at high temperature by dissolving boric acid or borax into hot water and then cool it to a room temperature, the solution recrystallizes and becomes a saturated solution at room temperature. Large amounts of boron are necessitated since the litter itself contains particles of solid metaborate that have been precipitating from the saturated solution during the spraying processes.
Consequently, the odor control agent is not homogeneously dispersed throughout the particles of the litter and the critical level of at least 0.06% equivalent boron is needed.
It is well known that in order to increase the solubility of borax, many researchers add sodium hydroxide to the aqueous borax solution. However, the mixture of borax and sodium hydroxide led to the formation of metaborate tetrahydrate, NaB(OH)4 -2H20, and this substance became to be commonly denoted by NaBO2 - 4H20.
As example, when 0.692g borax and 0.145g sodium hydroxide are dissolved in water, these two make 1.0g sodium metaborate tetrahydrate which precipitate in solution according to the following reaction.

6 Na 21340 7+ 2NaOH -> 4NaB0 2+ 2H 20 Moreover, Boron is adsorbed predominantly on clay minerals, iron and aluminium oxides and organic rnatter. Maximal adsorption occurs mostly in the alkaline range from pH 8 to 10, and decreases sharply to practically negligible amounts under acidic pH
conditions as reported by Goldberg & Glaubig 1.91185, 10RFn, 1 g~ah 10P8, uoron Q. Rin h~n, IvVV(w VVN, VV 1\l.llJll l,Jl lJlllgllUlll, 1985). Goldberg, S. & Glaubig, R. A. (1985) Boron adsorption on aluminum and iron oxide minerals. Soil Sci. Soc. Am. J. 49, 1374-1379. Goldberg, S. & Glaubig, R. A.
(1986a) Boron adsorption on California soils. Soil Sci. Soc. Am. J_ 50, 1173-1176.
Goldberg, S. & Glaubig, R. A. (1986b) Boron adsorption and silicone release by the clay minerals kaolinite, montmorillonite, and illite. Soil Sci. Soc. Am. J. 50, 1442-1448.
Goldberg, S. & Glaubig, R. A. (1988) Boron and silicon adsorption on an aluminum oxide. Soil Sci. Soc. Am. J. 52, 87-91.
Different kinds of boron adsorption mechanisms are known from the literature.
The pH
dependency of boron adsorption in terms of the percentage of boron present in ionic form (referenced to total boron) was described, the ionic form being adsorbed more readily than the uncharged form. In water, boric acid forms an ion by the addition of OH-to form the hydroxyborate ion B(OHY4. The first hydrolysis constant is Ki =
5.8-10-10 or 9.28 expressed as pK (at 20 C). Polyborate ions occur at higher boron concentrations, predominantly at high pH-values. The equilibrium between boric acid, monoborate ions and polyborate ions in aqueous solutions are rapidly reversible.
Because of the various differences of the above products, there currently exists a need for an animal or cat litter which is dust free, odorless (and thus natural smelling to the animal user) and trackless.
SUMMARY OF THE INVENTION
The present invention responds to the above-mentioned need by providing a dust and odor control particulate material, a process of making the same and a use of an aqueous solution of polyborate ions.
In one embodiment, the invention provides the use of a synthetic or vegetable oil sprayed onto animal litter in order to make a hydrophobic film on the surface of the swelling clay composition as a temporary water barrier film. Boron ions are adsorbed by clay minerals, thus explaining why the soil is enriched with respect to boron.
The clay's treatment with oil eliminates the dust and helps the odor control aqueous solution sprayed onto animal litter to be available on the surface of clay and not to be completely absorbed inside the clay particles. This process was efficient in controlling dust and urine odor. The critical level of aerosolized odor control composition is only 0.01%
equivalent boron which is 6 times less than the critical level reported by Ratcliff et al. Particulate substrate to which has been applied a liquid carrier containing a boron-containing material extends the life of litter with a good odor control to one month with no urine smell. This drastic increase in the borate concentration effect at low critical level is due to formation of the polyborate ions containing more boron atoms. Furthermore, none of the prior art has taught the combination of an odor control agent based on polyborate ions in combination with an organic solution, to provide long-term dust and odor control for animal litters.
In one embodiment, the invention provides a process for controlling dust and urine odors in cat litter. Perfumed odor control compositions have been used for thousands of years however these solutions did not destroy the odorous materials but instead they only masked the odors caused by the odorous materials. In contrast to this masking of the

7 troublesome odorous material in the prior art, the compositions of this invention react with the odorous molecules. In the prior art odor control compositions, are perfumes wtierein the odors are masked with a synthetic or natural essence. In the subject invention, instead of masking the odor with a perfume, the odor causing molecules are degraded by reaction with a very low concentration of polyborate ions. The use of borate is known in odor control and boron, as commercial borax, is an economical treatment, costing less than $2 per kg. The preferred sources of the borate moiety for use in accordance with this invention are Boric acid and Borax.
Most odor causing molecules are mercaptans, sulfides or amine based compounds, or other sulfur or nitrogen compounds. Polyborate ions are excellent agents for eliminating odors which are amine based. In one embodiment, this invention relates to the utilization of polyborate anions solution prepared from a critical ratio of Boric acid and Borax salt in aqueous solution, which react with odor producing molecules as may be contained in animal litters. The performance of the odor control compositions in accordance with this invention is further enhanced by the presence of small percentages of a dust-controlling agent onto the surface of the clay particles.
The present invention relates to novel process and additives for animal litter, in the eradication of malodor in the cat litters. More specifically, this invention is directed to a cat litter composition fornied principally from sodium bentonite and calcium carbonate in particulate form where the blend particles are treated, e.g. surface treated, with preferably aqueous solution of polyborate ions sprayed onto cat litters, thus inhibiting growth of urease positive bacteria for a period of several weeks, thereby retarding formation of ammonia. The composition of cat litter material is used after the well judged selection of particle size distribution such that the mean particle size of the non-swelling material is equal or greater than the mean particle size of the sodium bentonite.
The solubilities of boric acid and borax in water are not sufficiently high at room temperature, and thus there are technical difficulties in impregnating sufficient amount of the active constituent into cat litter. However, their solubilities in hot water are rather high but when the temperature decreases this causes the precipitation of crystals on surfaces of cat litter and results in some technical problems in the coating process.
In order to establish effective odor control of cat litter, a highly concentrated aqueous solution of borate at room temperature is wanted. These concentrated sodium borate solutions are useful as odor controlling agents because of a remarkable inhibiting urine effect for clay-based materials such as sodium bentonite.
In the present invention, we have successfully prepared a highly concentrated aqueous solution of sodium borate.
However, when the mixture of boric acid and borax was dissolved at a certain ratio in hot water as reported by lsao Tsuyumoto et al. in Inorganic Chemistry Communications 10 (2007) 20-22. The solution did not show recrystallization after cooling to room temperature. This was not oversaturation because the solutions remained transparent without any precipitation. lsao Tsuyumoto et al. suggested using the Raman spectroscopy and the APCI/MS (atmospheric pressure chemical ionization/mass spectrometry) analysis the formation of polyborate ions such as B,o 012 (OH)82-at a highly concentrated aqueous solution of sodium borate.

8 To our knowledge, boric acid and sodium tetraborate dissolved at high concentration in water have not been studied to control ammonia according to the process and preparation method reported in this invention.
According to one aspect of the invention, there is provided a process for making a dust and odor control particulate material, comprising : applying a dust control organic solution comprising vegetable, mineral or synthetic oil to substrate particles so as to form a water barrier film that is substantially unreactive to polyborate ions;
preparing an odor control aqueous solution comprising polyborate ions by mixing boric acid and borax in a ratio between about 0.825 and about 0.71; applying the odor control aqueous solution to the water barrier film so as to form an odor control layer at the surface of the substrate particles.
Optionally, the boric acid and borax ratio is about 0.79.
Optionally, the dust control organic solution is applied by spraying.
Optionally, after spraying the dust control organic solution, drying and blending the resulting particulate material before applying the odor control aqueous solution.
Optionally, the preparing of the odor control aqueous solution comprises heating an aqueous solution, adding the borax and the boric acid to form a highly concentrated solution and then cooling ttie highly concentrated solution without substantial precipitation of crystals.
Optionally, the dust control water barrier film is present in a concentration between about 0.2 wt% and about 3 wt% of the particulate material and has a thickness between about 15 and bout 250 microns.
Optionally, the concentration of boron in the odor control aqueous solution is above 2.5 rnol/kg, preferably above 3 mol/kg, still preferably above 3.25 mol/mg.
Optionally, the substrate particles comprise clay.
Optionally, the substrate particles comprise sodium bentonite.
Optionally, the sodium bentonite is present in a concentration between about 80 wt% to about 95 wt% of the particulate material.
Optionally, the clay is a clumping clay.
Optionally, the boron is present in a concentration between about 0.005 wt >o and about 0.05 wt% with respect to the particulate material.
Optionally, the odor control layer is present in a concentration between about 0.01 wt%
and about 0.03 wt% of the particulate material.
Optionally, the substrate particles comprise calcium carbonate.
Optionally, the calcium carbonate is present in a concentration between about 3 wt%
and about 20 wt% with respect to the particulate material.
Optionally, the dust control organic solution is anionic or non-ionic.
Optionally, the odor control aqueous solution has a pH of between about 8 and about 5.
Optionally, the odor control aqueous solution has a pH of between about 7.5 and about 6.5.
Optionally, the particulate material has a particle size distribution between about 8 mesh and about 100 mesh.

9 Optionally, the polyborate ions are available to react and inhibit bacterial urease and hydrogenase and the particulate material is an animal litter.
According to one aspect of the invention, there is provided a dust and odor control particulate rnaterial comprising: substrate particles;-a dust control water barrier film on the substrate particles formed from an organic solution comprising vegetable or synthetic oil, the water barrier film being substantially unreactive to polyborate ions;
an odor control layer formed from an aqueous solution comprising polyborate ions from boric acid and borax in a ratio between about 0.825 and about 0.71, the odor control layer being applied on the water barrier film to remain at the surface of the substrate particles.
Optionally, the boric acid and borax ratio is about 0.79.
Optionally, the dust control water barrier film is present in a concentration between about 0.2 wt% and about 3 wt% of the particulate material and has a thickness between about and bout 250 microns.
Optionally,the concentration of boron in the odor control aqueous solution is above 2.5 15 mol/kg, preferably above 3 mol/kg, still preferably above 3.25 mol/mg.
Optionally, the substrate particles comprise clay.
Optionally, the substrate particles comprise sodium bentonite.
Optionally, the sodium bentonite is present in a concentration between about 80 wt% to about 95 wt% of the particulate material.
Optionally, the clay is a clumping clay.
Optionally, the boron is present in a concentration between about 0.005 wt%
and about 0.05 wt% with respect to the particulate material.
Optionally, the odor control layer is present in a concentration between about 0.01 wt%
and about 0.03 wt% of the particulate material.
Optionally, the the substrate particles comprise calcium carbonate.
Optionally, the the calcium carbonate is present in a concentration between about 3 wt%
and about 20 v/t% with respect to the particulate material.
Optionally, the dust control organic solution is anionic or non-ionic.
Optionally, the odor control aqueous solution has a pH of between about 8 and about 5.
Optionally, the odor control aqueous solution has a pH of between about 7.5 and about 6.5.
Optionally, the water barrier film is dried-on.
Optionally, the material has a particle size distribution between about 8 mesh and about 100 mesh.
Optionally, the polyborate ions are available to react and inhibit bacterial urease and hydrogenase and the particulate material is an animal litter.
According to another aspect of the invention, there is provided a use of an aqueous solution comprising polyborate ions from boric acid and borax in a ratio between about 0.825 and aboL.it 0.71 as an odor control layer on the surface of a particulate material.
Optionally, the boric acid and borax ratio is about 0.79.
Optionally, the particulate material further comprises a dust control water barrier film onto which the odor control layer is applied, the water barrier film comprising vegetable or synthetic oil.
Optionally, the dust control water barrier film is present in a concentration between about 0.2 wt% and about 3 wt% of the particulate material and has a thickness between about 5 15 and bout 250 microns.
Optionally, the substrate particles comprise clay.
Optionally, the substrate particles comprise sodium bentonite.
Optionally, the sodium bentonite is present in a concentration between about 80 wt% to about 95 wt% of the particulate material.

10 Optionally, the clay is a clumping clay.
Optionally, the the boron is present in a concentration between about 0.005 wt% and about 0.05 wt% with respect to the particulate material.
Optionally, the odor control layer is present in a concentration between about 0.01 wt%
and about 0.03 wt% of the particulate material.
Optionally, the substrate particles comprise calcium carbonate.
Optionally, the calcium carbonate is present in a concentration between about 3 wt%
and about 20 wt% with respect to the particulate material.
Optionally, the particulate material has a particle size distribution between about 8 mesh and about 100 mesh.
Optionally, the particulate material is animal litter and the polyborate ions are used to inhibit bacterial urease and hydrogenase to control odors.
The optional aspects of the material, process and use mentioned here-above may be combined with various other optional aspects of the material, process and use mentioned here-above.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood and further advantages will become apparent when reference had to the following detailed description of the preferred embodiments of the invention and the accompanying drawing, in which:
FIG. 1 is a chemical structure of Boric acid H3BO3 OH
I

Ho~ oH
FIG. 2: Chemical structure of sodium metaborate (non-hydrated)

11 I

o8\O
I I 3 N a~
O0 / BOB\O0 Molecular formula: Na3B3O6, 12H20, Molecular weight: 413.58, Description:
White solid, odorless, Density: 1.90 g/mL at 25 C.
FIG. 3 is a chemical structure of H3B306 O--`B0 ~~ p- OH
B OH
I
OH
Hydrated metaborate FIG. 4 is a chemical structure of tetraborate H2B407 OH
O /
OH
O
B O--- B

FIG. 5 is a chemical structure of a polyborate: B,o 012 (OF06 OH
I
B
O \
j FI
O
O\ 0 B O~ B

B OH
\ ~ O B O B O
oH
B OH
O B

OH \ B \

FIG. 6 is a diagrammatic representation of the process of manufacturing dustless and

12 odor control clay composition for use as cat litter.
Raw Materials ctor Wal-ellouse jtcoiieJ

scep i Oc=gatni:, solution Bullc Production i Miaing Cliamber Arueous solution t step 2 PaCl:aging LDust joJIccto-Shipping J

DETAILLED DESCRIPTION OF PREFERRED EMBODIMENTS
This invention is concerned witi ~ dust and odor control technology and more particularly the composition contains 80% to 95% by weight sodium bentonite, 5% to 20% by weight calcium carbonate, 0.2% to 3% by weight dust control agent and 0.01% to 0.03%
by weight odor control agent. The animal litter composition is screened to a particle size between 8 mesh and about 100 mesh. To maintain the high quality of cat litter materials, we use different amounts (from 0% to 15%) of calcium carbonate depending on the physicochemical properties wanted. In order to provide cat litters that possess better absorption, diffusion and clurnping properties, we control the ratio (bentonite/calcium carbonate).
In accordance with this invention, odors attributed to cat litters can be coritrolled or eliminated. The odor control process of this invention comprises the application of an aqueous solution of the odor control composition of this invention, to an odor containina substrates, coated with a dust-controlling agent.
It was endeavored to determine if boric acid and sodium tetraborate are effective in controlling ammonia from used cat litters. Sonie specific objectives were:
(1) Deterniine the minimum effective concentration of organic solution -synthetic or vegetable oil- needed to eliminate dust and coat the surface of particles in order to form a temporary water barrier.

13 (2) Determine the minimum effective concentration of polyborate anions obtained from boric acid and tetraborate sodium in aqueous solution at 80 C to inhibit ammonia emissions in used cat litters.
(3) Deterniine the using time of cat litter where the dust and odor controlling agents were efficient.
Various embodiments of the invention provide the following characteristics and advantages:
- A process for controlling dust and odor on a substrate which comprises the steps of:
a) Applying an organic solution of vegetable or synthetic oil at an effective amount of dust control to the substrate wherein the solution essentially does not react with polyborate ions and, b) spraying an aqueous solution containing an effective amount of polyborate ions prepared from Borax and Boric acid according to the critical ratio of (Boric acid/Borax =
0.79).
- A dust coritrol additive produce by the above process, wherein the barrier coating has a thickness of about 15 to 250 microns.
- A process for manufacturing a dust and odor controlling cat litters as recited above, wherein the barrier coating comprises a first coating of said substrates with dust-control agent, followed by an odor-control agent composition coating. The concentration of the Boron may be from about 0.005 to about 0.05 weight percent; the concentration of sodium bentoriite niay be from about 80 to about 100 weight percent; the concentration of calcium carbonate may be from about 3 to about 20 weight percent; the dust controlling agent may be an anionic or nonionic organic liquid; the odor controlling agent may be an anionic or nonionic aqueous solution based on polyborate ions; and the odor controlling agent in an aqueous solution may have a pH of 7.4.
VVhile the invention will be described in conjunction with example embodiments, it will be understood that it is not intended to limit the scope of the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as rriay be included as defined by the present description and appended claims.
Example:
Clumping cat litter product is made from high quality absorbent clay. Sodium Bentonite clay is a naturally-occurring and is a naturally swelling clay known for its absorbent qualities (1g of sodium bentonite can absorb up to 8g of distilled water).
Sodium bentonite is composed of a combination of aluminum silicates and minerals.
A dust-controlling agent is added to the ground clay to prevent the dust, created when particles rub against one another, from becoming airborne. During the production process, the polyborate anions used as anti-bacterial agent were added to prevent odors.
Sample preparation Samples of raw material acquired from the suppliers were used with no further purification. 28 kg of experimental batches were produced using a small mixer, where all products needed were added simultaneously. Mixing lasted 3 to 5 minutes in each case, after which, a 10 kg sample was transferred into a bucket for future testing.

14 Testing The tests were completed according to the procedures in the test methods supplied by INTERSAND. The results were compared to the predetermined standards.
Materials and Methods:
1- Raw Materials:
Sodium Bentonite, Calcium Carbonate, Dust-controlling agent (oil), Anti-bacterial agent (Aqueous salts solution).
The pH of sodiuni bentonite is 10.00.
Sodium bentonite size distribution:
Sieve size Percentage Standards 12 0,1 0.5 max 25 81,9 80 min 40 16,8 100 0,8 1 max bac 0,13 0.2 max Sodium bentonite Dust (ppm):
Dust Level Sample (PPM) 1 15.5 14.7 3 16.3 Average 15.5 Moisture Content of sodium bentonite:
Sodium Bentonite %
Standards (target/max) 8 / 10 Average 8,90 Std. Dev. 0,58 min 7 max 10 Bulk Density of sodium bentonite:
Total average density: 0.974 g/ml 59.233 Ibs/ft3 Water absorption of sodiurri bentonite, Free Swelling Capacity (FSC):
FSC (%) ASTM
method Average 617 standards 500 rnin Calcium Carbonate or Limestone size distribution:
Sieve size Average (%) Standards 7 0,00 8 0,00 12 0,00 0.5 max 65,13 67 max 40 33,97 36 max 100 0,83 1 max Bac 0,10 0.1 max Limestone Dust (ppm):
Dust Level Sample (ppm) 1 25.7 2 28.3 3 26.1 Average 26.7 5 Moisture Content of Limestone:

limestone %
standards (target/niax) 0.2 / 1.0 Average 0,24 Std. Dev. 0,06 Bulk Density of Limestone:

Target 84; min 81,5; max 86,5 Ibs/ ft3 Average Density Sample Total mass (g) Mass (g) Density (g/ml) (g/ml) 1 565,3 367,1 1,343 2 565,1 366,9 1,342 1,341 3 563,7 365,5 1,337 4 563,2 365 1,336 81,540 lbs/ft3 Boric acid and sodium tetraborate were commercial grades. Boric acid H3BO3, has F.W.
61.83 and sodium tetraborate (Na2B4O7, 10H20) has F.W. 381.28.
Boric acid is a weak acid (Ka = 5.8 X 10-10), slightly soluble in water and contains 17.5 %
boron. The solubility of boric acid in distilled water is 5,04 g/100 ml at 20 C (Lange reference), corresponding to 4.8%. The pH of aqueous boric acid solution ranges from 6.1 at 0.16 g/L to 3.7 at 7.6 g/L. Sodium tetraborate decahydrate (borax) is slightly soluble in water and contains 11.35 % boron. The solubility of borax in distilled water is 5,1 g/100 ml at 20 C (ISSP reference), corresponding to 4.9%. The pH of the aqueous borax solution is 9.2 and almost constant over a wide range of concentration.
Borax or Boric acid size distribution:
Sieve size Average (%) On 8 0 On 100 90,5 Bulk Density of Borax or Boric acid:
Borax decahydrate Staridard 99,8% 99,8 % min Preparation techniques Organic solution - synthetic or vegetable oil- used herein in this example was synthetic oil P10T. This P10T oil was used as received.
Preparation of aqueous solution of odor controlling agent:
Dissolution of alkaline metallic borates in aqueous media is faster than the others and dissolution rate of borates in general is increased with increasing temperature. Boric acid and borax dissolve faster in hot waters than cool waters. The temperature used to dissolve borax and boric acid in this example is 80 C. The odor control aqueous solution of this invention containing active ingredients which will react with the odor generating material has pH = 7.4. The solutions of this invention are effective on different kind of clay over a pH range of 6-14.
The equilibriuni which occurs in various aqueous solutions of boric acid and borate has been extensively studied. From the results it is clear that, in addition to the mononuclear boric acid and orthoboric ion which have been well established by infrared and Raman spectroscopy to be trigonal B(OH)3 and B(OH)-4 species, a number of polyborate ions also are formed.
B(OH)3 + H20 -> B(OH).4 + H+
The aqueous chemistry of the borates is dependent on concentration and pH.
Dilute aqueous boric acid solutions are comprised solely of B(OH)3 and B(OH)4 species.
2- Recipe No. 1 of Anti-bacterial agent:
83% Water, 9.3% Borax Decahydrate 7.4% Boric acid A highly concentrated aqueous solution of sodium borate was prepared at 80 C
with pH
= 7.4. This is more than twice more concentrated than the most soluble known borate.
The solution was prepared by dissolving 7.4 g of boric acid and 9.3 g of borax into 83 g of hot water over 70 C did not recrystallize at 20 C. Chemical structure presented in FIG. 5 for polyborate B,o 012 (OH)c, is considered to be the principal polymer formed by condensation of the conventional borate ions derived from boric acid and borax. This gives a ratio of moles of boron/kg or solution of 2.17.
Recipe No. 2 of Anti-bacterial agent:
75% Water 13.9 % Borax Decahydrate 11.1 % Boric acid This gives a ratio of moles of boron/kg of solution of 3.26. This is well above 2.5 moi/kg.
In theses conditions the pH is situated between 6,5 et 7.
3- Formula of cost effective cat litter from recipe No. 1:
85% Sodium Bentonite,

15% Calcium Carbonate, 1% Dust-controlling agent, 0.5% Anti-bacterial agent Formula of cost effective cat litter from recipe No. 2:
0.334 % of the anti-bacterial agent 4- Manufacturing steps:
The production process of cat litter is based on clay and Calcium carbonate.
The raw materials are used as received and mixing represents one of the key manufacturing steps for products. The dust-controlling and odor-controlling agents are in the liquid form.
They are sprayed sequentially in the mixer onto the blended clay and calcium carbonate.
The particulate substrate to which has been applied a dust-controlling agent is dried and blended for a period of time before to be treated with the odor-controlling agent.

Cat litter Clumping (%):
Product Clumping (%) 88 target, 85 Standards min Sample 1 88,5 Sample 2 87,4 Saniple 3 88,3 Cat litter Dust (ppm):
Dust Level Sample (PPM) 1 0.704 2 0.645 3 0.567 4 0.571 0.563 6 0.593 7 0.714 8 0.686 9 0.633 0.686 Average 0.636

Claims