US009010273B2

(12) United States Patent (10) Patent No.: US 9,010,273 B2 Adamy et al. (45) Date of Patent: Apr. 21, 2015

(54) ABSORBENT COMPOSITION FOR 6,280,495 B1 8, 2001 Doetsch et al. MITIGATING FECAL ODOR 7,331,309 B2 2/2008 Burckbuchler, Jr. 7,393,521 B2 7, 2008 Hruza 7,419,593 B2 * 9/2008 Trauger et al...... 210,502.1 (75) Inventors: Steven T. Adamy, Lawrenceville, NJ 7,468.469 B2 12/2008 Hollabaugh et al. (US); Lauren Ciemnolonski, Princeton, 7,603,964 B2 10/2009 Jenkins et al. NJ (US); Frederick Lawson, Somerset, 7,665,418 B2 2/2010 Bracilovic NJ (US) 2002/0102229 A1 8/2002 Wegner 2006/0088498 A1 4/2006 Martin et al. 2008/0223302 A1 9/2008 Wang et al. (73) Assignee: Church & Dwight Co., Inc., Princeton, 2009 OO69181 A1 3, 2009 Boulos NJ (US) 2009, O169630 A1 7, 2009 Ward et al. (*) Notice: Subject to any disclaimer, the term of this FOREIGN PATENT DOCUMENTS patent is extended or adjusted under 35 U.S.C. 154(b) by 631 days. DE 4101243 A1 7, 1992 DE 410 1243 A1 * T 1992 (21) Appl. No.: 12/896.569 WO WOOO,53001 9, 2000 OTHER PUBLICATIONS (22) Filed: Oct. 1, 2010 O O Print out of the search results and definition of the chemical com (65) Prior Publication Data pound known as silicic acid, as cited in the Encyclopaedia Britannica US 2012/OO79989 A1 Apr. 5, 2012 website (http://www.britannica.com/EBchecked/topic/544289/ silicic-acid) and last updated as of Sep. 18, 2013. (51) Int. Cl. AIK 29/00 (2006.01) * cited by examiner BOI 20/00 (2006.01) AOIK L/05 (2006.01) Primary Examiner — Anthony J Zimmer (52) U.S. Cl. (74) Attorney, Agent, or Firm — Fishman & Associates, CPC ...... A0IK I/0152 (2013.01); A0IK I/0154 LLC; Jai-Wei Fishman (2013.01); Y10S 502/526 (2013.01) (58) Field of Classification Search (57) ABSTRACT CPC ...... A01K 1/O154: A01K 1/O155 The present invention is directed towards an absorbent com USPC ...... 502/400, 407, 414, 415, 411, 526; position and its method of production and use. More specifi 119) 171, 173 cally, the present invention relates to an absorbent composi See application file for complete search history. tion comprising a liquid absorbing material, at least one alkaline earth metal peroxide, and an acidic material. The acid (56) References Cited maintains a high hydrogen peroxide release profile under U.S. PATENT DOCUMENTS acidic conditions, such that the composition is found Surpris ingly effective in mitigating fecal odor. 4.405,354 A 9/1983 Thomas, II et al. 6,110,479 A * 8/2000 Blaney et al...... 424/402 19 Claims, 2 Drawing Sheets U.S. Patent Apr. 21, 2015 Sheet 1 of 2 US 9,010,273 B2

Fig. 1

OO -O-MgO2 (Aldrich) 80 -A-CaO2(Aldrich)

60 % of TheOr. Max. H2O 40

20

O pH

Fig. 2

100

80 more % of Theor. 60 Max.ax. HOH2O2 40

20 U.S. Patent Apr. 21, 2015 Sheet 2 of 2 US 9,010,273 B2

Fig. 3 100 -O-MgO2(Aldrich) -A-CaO2(Aldrich) 80 -C-Sample B

60 % of TheOr. Max. H2O 40

20

O pH

100 -O-MgO2(Aldrich) - HSample A 80 -A-CaO2(Aldrich) -v-Sample C 60 % of TheOr. Max. H2O 40

20 US 9,010,273 B2 1. 2 ABSORBENT COMPOSITION FOR Another example is WO2000/53001 to Simmler MTIGATING FECAL ODOR Hibenthal et al., disclosing an animal litter containing thyme camphor and/or at least one solid peroxo compound to reduce FIELD OF THE INVENTION Smells. Anotherexample is U.S. Application No. 2006/0088498 to The present invention relates to an absorbent composition Martin et al., describing a solvent activated antimicrobial and its method of production and use. Particularly, the present oxidizing agent comprising a reactor Such as magnesium invention relates to an absorbent composition comprising a peroxide and/or calcium peroxide within a reactor core for liquid absorbing material, at least one alkaline earth metal treating animal litter, and that Such oxidizing agent may be peroxide and an acidic material, wherein the composition is 10 used to eliminate odor related to microbes on ice in ice found Surprisingly effective in mitigating fecal odor. machines. However the composition of Martin et al. requires a reactor wall Such as a porous membrane to control the BACKGROUND OF THE INVENTION release of solvent to the reactants and the diffusion of the oxidizing agent. Before the advent of litters, pet owners had relegated pets 15 to outside the home for lack of an area for taking care of pet SUMMARY OF THE INVENTION excrement. Litters allow pets to take care of waste functions An absorbent composition comprising a liquid absorbing and live inside the home. Housebroken animals, such as cats, material, and a combination of at least one alkaline earth are trained into the habit of urinating and defecating in a metal peroxide and an acidic material selected from citric specially provided litter box. Similarly, untrained and caged acid, Zinc chloride and malic acid, has been found Surpris animals, such as guinea pigs, urinate and defecate on the floor ingly effective in mitigating fecal odor. The liquid absorbing of their cage, often in approximately the same floor area of the material is a clumping or non-clumping material known in the cage. Consequently, pet owners, homeowners, Veterinarians art. and laboratory personnel have added liquid absorbing mate 25 rials to the litter box or cage to collect the urine and feces. BRIEF DESCRIPTION OF THE DRAWINGS The most commonly used litter box liquid absorbing mate rials are inexpensive clays, such as calcined clays, that are For a fuller understanding of the nature and advantages of safe and non-irritating to the animals, and that absorb Sub the present invention, reference should be made to the fol stantial amounts of liquids. Other porous, solid litter box 30 lowing detailed description read in the conjunction with the absorbent materials, that are used alone or in combination, accompanying drawings. include Straw, sawdust, wood chips, wood shavings, porous FIG. 1. Illustrates the percentage of hydrogen peroxide polymeric beads, shredded paper, sand, bark, cloth, ground release from magnesium peroxide and calcium peroxide at cornhusks, and cellulose. Each of these absorbent materials pH range of 6 to 11. 35 FIG. 2.Illustrates the hydrogen peroxide release profile for has the advantage of low cost. The entire contents of the litter a commercial grade (75% active) calcium peroxide at a pH box including the Soiled and unsoiled liquid absorbing mate range of 3 to 11. rials will eventually be removed, because of the offensive FIG. 3. Compares the hydrogen peroxide release profiles odor caused by the absorbed urine and feces. (% of Theor. Max. H2O) of various grades of alkaline earth Many litters adequately control the odor associated with 40 metal peroxides at a pH range of 5 to 12. urine. This is typically done through simple absorption of FIG. 4. Compares the hydrogen peroxide release profiles liquid, which counteracts the growth of odor-causing bacte (% of Theor. Max. H2O) of various grades of alkaline earth ria. Currently clay soils or comminuted rocks, e.g. the sodium metal peroxide at a pH range of 5 to 12. bentonites, are used to improve litter compositions. Sodium bentonites not only absorb liquid waste Such as urine, but they 45 DETAILED DESCRIPTION OF THE INVENTION also absorb the odor associated with the liquid waste, as the material binds amine compounds in the face sites’ of the clay An absorbent composition for mitigating fecal odor com interlayers. prises a liquid absorbing material and a combination of at However, clay litters composed of sodium bentonites or least one alkaline earth metal peroxide and an acidic material other materials do not address the issue of fecal odor. Fecal 50 selected from citric acid, Zinc chloride, and malic acid. The odor differs from urine odor in that the odor is produced liquid absorbing material can be clumping or non-clumping, immediately at the time of the defecation, whereasurine odor, Such as natural clumping clays, e.g. sodium bentonite, non being produced by the action of microbes, evolves in the days clumping clays, non-clumping clays combined with clump following urination. Materials in fecal odor that carry an ing agents, non-clay materials or non-clay materials com especially strong impact include butyric acid, p-cresol, ska 55 bined with clumping agents, or any mixture of the above tole, and dimethyltrisulfide. materials. Liquid Absorbing Material DESCRIPTION OF THE PRIOR ART Commonly used liquid absorbing material for animal lit ters are clays. The water-absorbent clay component of the A variety of methods and compositions have been 60 animal litters of this invention may be, for example, a clay soil described in the prior art for preparing animal litter to combat or comminuted rock containing at least one water Swellable offensive odor. One such example is U.S. Pat. No. 4,405.354 clay mineral. Such clay mineral may be, for example, a mont to Thomas II, et al., describing a method for controlling morillonoid or Smectite, having a three-layer, sheet structure ammonia odor from organic waste by monobasic salts of crystal lattice with two layers of silicon/oxygen tetrahedrons dibasic acids, and mono-, di- or tri-basic acids, such that the 65 between which is a central layer of aluminum and/or magne acid has a dissociation constant pK, less than the correspond sium/oxygen dioctahedrons or trioctahedrons. Part of the sili ing dissociation constant of aqueous ammonia. con in the tetrahedral layers may be substituted with alumi US 9,010,273 B2 3 4 num and part of the aluminum and/or magnesium in the invention and may or may not be treated with clumping agents central octahedral layer may be substituted with other ele include Zeolites, crushed stone (like dolomite), light density ments such as lithium, chromium, Zinc, or iron. Contemplated aggregates and silica gels. It should be noted that clumping montmorillonoid clay minerals are montmorillonite and non clays, such as Sodium bentonite, might feasibly be mixed with tronite containing a dioctahedral central layer, and hectorite, any of the above materials to form a water absorbing material. saponite, and Sauconite containing a trioctohedral central Still other liquid absorbing materials may be made of suit layer. able organic based litter. These natural products include, and When the foregoing montmorillonoid clay minerals are are not limited to. Such materials as wood based materials contacted with water or water vapor, the water molecules Such as wood chips, wood shavings, wood flour, sawdust; penetrate between the layers causing interlayer or intracrys 10 Straw; clay; porous beads such as those of polyethylene, talline swelling and expansion of the entire lattice. This polypropylene or polystyrene; paper based materials such as causes the particles of clay component in the animal litter to shredded paper, cloth; alfalfa, cotton; sand; bark; ground corn agglomerate thus facilitating the removal of only that portion husks; ground Sugar cane; lignocellulose; cellulose, calcium of the litter, which is swelled by urine or other aqueous waste silicate; calcium sulfate; various grains (corn, wheat, flax liquid. 15 etc.); or cellulosic products such as sawdust, woodchips or The often-used clay component of the animal litter of the plant hulls. present invention is a comminuted bentonite, more preferably Clumping Agent a sodium bentonite, which contains a preponderant amount of Clumping agents, or clump enhancing materials, may be montmorillonite clay mineral. The use of bentonite clays in a used in connection with the present invention and those are variety of applications, such as a component in drilling muds, known in the art Such as clumping clays, polysaccharides, is well known. Bentonites are economical, readily available water-soluble gums, dry particulate cellulosic ethers and clays, with certain forms capable of hydrating and Swelling in water absorbent polymers, or mixture thereof. Clumping the presence of water. The swelling properties of bentonite agents promote adhesion of the fine size particles of litter are related to the exchangeable cations present in a particular Substrates to each other as well as promoting adhesion of the bentonite ore. The water-swellable bentonite clays contain 25 granules to form agglomerate when wetted. Preferably, the various exchangeable cations, including Sodium, potassium, clumping agent allows the formation of gelled agglomerate lithium, ammonium, calcium and magnesium. Although any when exposed to a liquid, such as animal urine. of these cations can be the predominant exchangeable cation Natural occurring polymers which may be used in connec of the bentonite clay of the present invention, bentonite clays tion with the present invention include, for instance, gum often include a variety of exchangeable cations. 30 arabic, gum karaya, gum tragacanth, gum ghatti, guar gum, The water-swellable bentonite clays useful in the fecal alginates, carrageenan, pectins, starches, dextran, Xanthan odor absorbent composition of the present invention include gum, gelatin, gluten, cornstarch and dried plants of the Plan any water-swellable bentonite clay that hydrate in the pres tago family. An example of a suitable gum-clumping agent is ence of water, e.g., Swell in the presence of water. The water a water-soluble galactomannan gum, Such as a guar gum or a Swellable bentonite clay is selected from the group consisting 35 locust bean gum, or an ether derivative thereof, that forms a of sodium bentonite, potassium bentonite, lithium bentonite, gel upon contact with liquid. Suitable clumping agents of calcium bentonite and magnesium bentonite, or combination vinyl polymers include polyvinyl alcohol, polyvinyl esters thereof. The bentonite clay can be any member of the dioc Such polyvinyl acetate, polyvinylpyrrolidone, polyvinylox tahedral or trioctahedral Smectite group, or a mixture thereof; aZolidone, polyvinyl methyloxazolidone, copolymers and examples include Montmorillonite, Beidellite, Nontronite, 40 mixtures thereof. Hectorite and Saponite, or combinations thereof. Semisynthetic polymers useful as clumping agents in the Clays dominate the animal litter market. However, the present invention include cellulose ethers and guar gum naturally clumping clays are not the only sorts of water derivatives. The cellulose ether can be methylcellulose, absorbing material useful in the litter. As mentioned above, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylhy other water absorbing material may be used as litter Such as 45 droxyethyl cellulose, methylhydroxypropyl cellulose, car non-clumping clays, which may or may not be converted to boxymethyl cellulose, hydroxypropylmethylcellulose or clumping clays with the addition of clumping agents. mixtures thereof. A combination of various vinyl, natural and These non-clumping clays include Attapulgite, Fuller's semisynthetic polymers can be used as clumping agents in the earth, calcium bentonite, palygorskite and sepiolite. The Full present invention. er's earth clay, also referred to herein as Fuller's earth or clay, 50 Useful polymers (such as Super absorbent polymers) are constituent of the compositions of this invention is a natural, preferably capable of absorbing many times their own weight earthy material composed primarily of hydrous aluminum of an aqueous fluid Such as urine. The formed agglomerates silicates, while Small amounts of non-clay materials can also have Sufficient mechanical integrity to be conveyed from a be present. Calcium bentonites can range in color from a litter box as a discrete entity using methods typically used in cream, off-white to a dark reddish tan color and are frequently 55 removing waste product from a litter box such as with imple referred to in the trade under designations such as Mississippi ments or manually by hand. Brown and Miss. White. These animal titter clays can be Other useful clumping agents useful in the present inven divided into heavy weight clays and lightweight clays. Full tion are commercially available, for example, commercially er's earth and calcium bentonite are heavy weight clays. available cellulose ethers such as methylcellulose A4M and Sepiolite and attapulgite (palygorskite) are lightweight clays. 60 hydroxypropylmethylcellulose J15MS, E15LVP. K4M and Other clays useful as the liquid absorbing material in the K15M, are all available from The Dow Chemical Company. litter of this invention may include kaolinite, illite, halloysite, Various starches, including Starch 1500, are available from hormite, vermiculite or mixtures thereof. Colorcon, a division of Berwind Pharmaceutical Services, With the large part of the animal litter market being domi Inc. As another example, guar gum is available from Aqualon nated by clumping and non-clumping clays, the remainder of 65 Company. the market is made up of a variety of nonclay Substances. In addition, filler materials such as limestone, sand, calcite, Examples of non-clay materials that can be used in the present dolomite, recycled waste materials, Zeolites, and gypsum can US 9,010,273 B2 5 6 also be incorporated with the clay materials to reduce the cost two components are mixed and pelleted together, then of the litter without significantly decreasing the materials crushed and sieved to make co-granules of particle size range performance as a litter. from greater than 34 microns to less than 2400 microns. Alkaline Earth Metal Peroxides It is believed that the incorporation of the acidic material Alkaline earth metal peroxides such as magnesium peroX serves the following purposes: 1) maintains a low local pH in ide or calcium peroxide are incorporated into the absorbent the absorbent composition Such that hydrogen peroxide is composition, and they are known for bleaching, disinfecting, generated in high percentage to mitigate fecal odor; and 2) and deodorizing. The peroxides release hydrogen peroxide ensures the stability of hydrogen peroxide in the low local pH (HO) upon contact with a hydrous fluid: environment. A high release of hydrogen peroxide at a low pH 10 condition is characterized by greater than 50% of hydrogen peroxide release at pH 6.3 or less. A slow release of hydrogen peroxide at a higher pH condition is characterized by no more Different alkaline earth metal peroxides have different than 40% of the theoretical maximum of hydrogen peroxide hydrogen peroxide release profiles. As shown in FIG. 1, Mag 15 release between about pH 8 and about pH 9. nesium peroxide (about 26% active MgO, technical grade, Formulation obtained from Aldrich Chemical) displays a lower degree of The absorbent composition comprising a liquid absorbing hydrogen peroxide release at a pH of about pH 8.5 to 10, but material and at least one alkaline earth metal peroxide are a high degree of release (>80%) at about pH 6.3. Meanwhile, incorporated herein to provide an improved absorbent com calcium peroxide (about 75% active CaO, technical grade, position comprising a liquid absorbing material and a com from Aldrich Chemical) displays a high degree of hydrogen bination of at least one alkaline earth metal peroxide and an peroxide release (s80% to 5%) at a pH of about 8.5 to 10, with acidic material. close to zero or minimal release beyond pH of 10. The liquid absorbing material used in the formulation is in It can be shown that an alkaline earth metal peroxide with the amount of 50 to 99 Wt.%, also an amount of 50 to 95 Wt. a high degree of release of hydrogen peroxide at a low pH 25 % are useful. The alkaline earth metal peroxide used is (below about pH 9) is effective in mitigating fecal odor. present in an amount of from 0.5 to 47.5 Wt.% of the absor Therefore it is desirable to lower the pH of the alkaline earth bent composition, also the amount of from 0.01 to 49.5 Wt.% metal peroxide to maximize the release of hydrogen peroxide. are useful. The amount of the acidic material used in the Reducing the pH further increases the stability of the HO composition is from 0.05 to 25 Wt. '% of the absorbent com that is generated. Furthermore, as illustrated in FIG. 2 that it 30 position, also the amount of from 0.01 to 49.5 Wt. '% are is possible to maximize the hydrogen peroxide release by useful. The acidic material is preferably co-granulated with at lowering the pH of the alkaline earth metal such as calcium least one alkaline earth metal peroxide. The amount of the peroxide by adding an acidic material. Either powder or co-granules used in the absorbent composition is from about granulated alkaline earth metal peroxide can be blended with 1 Wt.% to about 50 Wt.%, also the amount of from 5 Wt.% a liquid absorbing material to produce the absorbent compo 35 to about 50 Wt. '% are useful. The total amount of alkaline sition. It can be also be shown that a high degree of peroxide earth metal peroxide used to form the co-granules is about 1 release at a high pH (above about pH9) is not effective in odor to 99%, preferably 50 to 95%, and the amount of acidic mitigation. This may be due to the inherent instability of material used to form the co-granules is about 1 to 99% H2O at high pH. Though peroxide generation can be signifi preferably 5 to 50%. The ratio of the alkaline earth metal cant, quick degradation of HO may render it ineffective 40 peroxide to the acidic material is from 1:1 to 19:1, preferably against odor compounds. 10:1. The ratio of the co-granules to the liquid absorbing Although the above discussion is focused on absorbent material is from 1:99 to 1:1, preferably 1:19. compositions comprising alkaline earth metal peroxide, it is Optional Components possible that other inorganic or organic peroxides, or peroX The absorbent composition optionally includes a filler as ide adducts may also be used as a replacement for or in 45 described hereinabove, a de-dusting agent and/or fragrance. addition to the alkaline earth metal peroxide. An Example of The de-dusting agent is selected from water-soluble poly organic peroxide includes benzoyl peroxide. Examples of meric resins, e.g., polyvinyl alcohol, polyvinyl acetate, poly inorganic peroxides include bariumperoxide and manganese vinyl pyrrolidone, polyacrylic acid, guar gum, Xanthan gum, peroxide. An example of a peroxide adduct includes urea gum arabic, other natural resins and mixtures of any of these peroxide. 50 resins. An inorganic dusting agent, such as calcium chloride, Acid can also be used. If a fragrance is utilized, an amount of The acidic material suitable for lowering the pH of the fragrance in an acceptable range, typically from 0.01-10%. alkaline earth metal peroxide can be in the form of either can be employed. The fragrance could be added to the absor liquid or Solid granules. Inorganic acids including Lewis acid bent composition during the process of making the composi or organic acids can be used, i.e. citric acid, Zinc chloride and 55 tion or after the absorbent composition is made. malic acid, and related acids have been found useful. The Method of Use preferred acid form is a granulated solid and the preferred Solid waste such as feces is in full contact with the absor acid material is citric acid. bent composition on at least one surface or phase, with the Combination of Alkaline Earth Metal Peroxides and an remaining surface area of the feces covered with at least 10% Acidic Material 60 of the absorbent composition. The acidic material can be incorporated into the absorbent The litter compositions of this invention may be used for a composition by blending the acidic liquid or solid granules wide variety of animals and birds, e.g., un caged household with at least one alkaline earth metal peroxide. Spraying the pets Such as cats and dogs, particularly puppies too young to acidic material in liquid form onto the alkaline earth metal be walked, caged pets such as hamsters, gerbils and rabbits, peroxide to form a coating may be useful. The acidic material 65 caged laboratory animals such as guinea pigs, mice, rats and in Solid form can also be co-granulated with at least one monkeys, animals raised for fur Such as mink, barnyardbirds alkaline earth metal peroxide. Specifically, granules of the Such as chickens, ducks and geese, and pet birds such as US 9,010,273 B2 7 8 parrots, parakeets, canaries and pigeons. The compositions of that peroxide generation was predominant at acidic pH val this invention are particularly suitable for use as cat litters. ues, leveling off at about pH 5. Example 1 Example 3 Procedure for Blending Powder Metal Peroxide into A preliminary Smell test was conducted to determine the Litter effectiveness of the alkaline earth metal peroxides for miti gating fecal odor. During the test, panelists were asked to Smella large jar containing feces analog (Malodor #1 and #2, 10 simulators of fecal malodor) embedded in litter that contained Formulation (by weight) either magnesium peroxide or calcium peroxide. The panel 50% Dolomite, Limestone ists Subsequently rated the malodor on a scale of 0 (no odor) 2.0% DIWater to 6 (extreme odor). The results are shown below: 0.2% Guar Gum 15 2.0% Alkaline earth metal peroxide (powder) q.S. Sodium Bentonite (unscented)

Wt.% of Unscented Scented Total 100% MgO2 score (0-6) Score (0-6) In a kitchen-aid mixer, dolomite, water and guar gum were blended together. Alkaline earth metal peroxide powder was (Aldrich With WO With WO added to wet dolomite by gentle mixing to coat the dolomite Tech.grade) Malodor MgO2 MgO2 MgO2 MgO2 completely. Sodium bentonite was added to the dolomite blend and gently mixed. Two separate samples were made 2 1 2.53 2.76 25 with the above formulation, each contained 2.0 Wt. '% of 2 2 2.15 3.38 1.24 2.OO powder metal peroxide: IxperR 35M (about 35% active MgO, from Solvay Chemicals) and IxperR 75C (about 75% 1 2 2.60 3.93 active CaO). The samples were labeled accordingly as “Sample A” and “Sample B'. 30 Procedure for Blending Granular Metal Peroxide into Litter

Wt.% of CaO, Formulation (by weight): (Aldrich Unscented score (0-6) Scented 5% granular metal peroxide 35 Tech.grade) Malodor With CaO, W/O CaO. Score (0-6) q.S. Sodium bentonite (unscented) Total 100% 2 2 3.65 2.76 Not tested Sodium bentonite and granular metal peroxide were 40 blended together and gently mixed. Two samples were made It can be shown that magnesium peroxide had Superior with the above formulation, each contained a granular metal fecal odor mitigating property as compared to calcium per peroxide: IxperR 70C (about 70% active CaO, from Solvay oxide. Specifically, the panelists consistently smelled less of Chemicals) and Ixper(R) 30M (about 30% active MgO from the malodor (score of 2.15 to 2.60) for the unscented litter at Solvay Chemicals). The samples were labeled accordingly as 1 or 2 Wt.% of magnesium peroxide, as compared to 2 Wt.% 45 “Sample C and “Sample D'. of calcium peroxide (score of 3.65). Procedure for Making Co-Granule: From FIG.1, it might be expected that the Aldrichtechnical grade CaO would be effective in mitigating fecal odor, since a higher level of peroxide is produced compared to MgO at Formulation comparable pH values. Surprisingly, this was not the case. 50 95.0% Sodium bentonite (unscented) Subsequent examples show that the pH-release profile of the 4.5% Magnesium peroxide MgO2 plot in FIG.1 appears to be corresponding to improved 0.5% Citric Acid odor mitigation. Total 100% 55 Example 2 10% citric acid, 90% magnesium peroxide by weight were blended and mixed well. A pellet die set was coated with a Small amount of magnesium Stearate. The citric acid/magne A commercial study was conducted by Solvay Chemicals sium peroxide blend was added to the pellet die set (roughly to show that by lowering pH of the metal peroxide, the release 60 /8" thick), and the complete die set was inserted into the of HO could be altered. In this study, sulfuric acid was Carver Autopellet Lab Press (Model #3887) to pelletize the added to 0.2% slurry of Ixper R75C (about 75% active CaO). mixture. The pellets were crushed with a mallet by hand then A portion of the slurry was filtered and tested for HO poured through a series of sieves. The crushed pellets that content. Acid was added to remaining slurry to obtain a lower passed through a U.S. sieve size 8 (Smaller than 2.4 mm pH. Filtration and analysis were then performed again. The 65 diameter) and did not pass through a U.S. sieve size 40 (i.e. process was repeated to examine H2O over a wide pH range larger than 0.043 mm diameter) were recovered. The process of 3 to 11. Results are illustrated in FIG. 2, where it is shown was repeated until enough granules were made. 95 Wt. '% US 9,010,273 B2 9 10 sodium bentonite was blended with 5 Wt. 9% of the magne TABLE 2 sium peroxide/citric acid granules and gently mixed. Summaries of litter compositions evaluated are shown Significant Differences and pValues below: 667 vs. 105 p = 0.0001 667 vs. 409 p = 0.0001 667 vs. 637 p = 0.0001 Material Description Wt.% in litter 214 wS. 105 p = 0.0001 214 wS. 409 p = 0.0002 Sample A 35% Magnesium 2 214 wS. 637 p = 0.0240 Peroxide 637 vs. 105 p = 0.0240 Sample B 75% Calcium 2 10 Peroxide Sample C 70% Calcium 5 In FIG. 3, hydrogen peroxide release profiles of Sample B Peroxide Sample D 30% Magnesium 5 and Sample C were similar to that of MgO (Aldrich). It is Peroxide believed that by having a similar hydrogen peroxide profile, MgO2 + Citric Co-granules of MgO2 5 15 Sample C performed well in mitigating fecal odor (score of acid co-granules and citric acid (%) 2.09). Sample B, with a profile similar to that of (Aldrich) CaO, showed a poor degree of odor mitigation, like the Each of the unscented litter composition contained a feces Aldrich CaO. model incorporating Malodor #3 (simulator of fecal malodor Sample D also showed poor performance. In FIG. 4, developed by Church & Dwight) with at least one surface area Sample D had a hydrogen peroxide release that was some in full contact with the absorbent composition, and at least what steeper than that of the (Aldrich) MgO,. It is believed 10% of the remaining surface area covered with the absorbent that the short and steep release of hydrogen peroxide was composition. Each litter sample was located in a separated indicative of properties that contributed to the poor efficacy in booth with high evacuation. Panelists entered their assigned attacking strong fecal odor present in the sample (score of 25 4.77). booths at one panelist per booth, washed their hands with It is shown from Table 1 that co-granules of MgO with unscented soap and blotted dry. They were then asked to sniff citric acid performed the best to mitigate fecal odor. This was simulated cat feces sample as the reference sample and rated no doubt due to not only an improved efficiency of peroxide them for odor intensity on a seven-point Scale (0 no odorand release at the lower local pH, but an improved HO stability 6-maximum odor). Each Panelist completed the task once. 30 due to the lowered pH. Therefore, by lowering the pH of the They assessed the reference sample as a 6 on a 7-point scale. system with the incorporation of an acid, the hydrogen per The Panelists assessed a test sample containing Malodor oxide release was maximized to best mitigate fecal odor. #3 and rated it for intensity. After waiting for one minute and Sniffing an unscented tissue they repeated the process with the second test sample in the appropriate booth. The process was 35 What is claimed is: repeated until all five testing samples had been assessed. 1. A particulate animal litter composition comprising a All statistical analyses were based on the odor intensity liquid absorbing material, and a combination of a co-granule scores. The comparison of the study treatments employed an of 1) at least one alkaline earth metal peroxide and 2) an acidic analysis of variance (ANOVA) model. This ANOVA model material, wherein said liquid absorbing material forms no part included the fixed factor product and the random factor pan 40 of said combination. elist. Post-ANOVA pairwise product comparisons were per 2. The particulate animal litter composition of claim 1, formed using t-tests. Tukey's method was utilized to adjust wherein said liquid absorbing material is selected from the for multiple comparisons. All statistical tests of hypotheses group consisting of clumping and non-clumping clay. were two-sided, and employed a level of significance of 3. The particulate animal litter composition of claim 2, O=0.05. 45 wherein said liquid absorbing material is sodium bentonite. Results: 4. The particulate animal litter composition of claim 2, Table 1 provides a summary of the mean scores for each wherein said liquid absorbing material optionally includes a product. clumping agent. TABLE 1. Summary of Mean Odor Intensity Scores

105 409 214 637 Sample A Sample B Sample C Sample D Citric Acid granules

N Mean SD Mean SD Mean SD Mean SD Mean SD

22 477 1.41 4.OO 1.72 2.09 1.23 3.36 1.79 1.27 1.52

60 Table 2 provides p values for significant differences. Products 5. The particulate animal litter composition of claim 4, wherein said liquid absorbing material is selected from the 667 and 214 received the lowest intensity scores and were not group consisting of kaolinite and attapulgite. significantly different from each other. They were followed 6. The particulate animal litter composition of claim 1, by 637, 409 and 105 and were both significantly lower than 6s wherein at least one alkaline earth metal peroxide is selected 637, 409, and 105. Product 637 was significantly lower than from the group consisting of magnesium peroxide, calcium Product 105. No other significant differences were detected: peroxide and barium peroxide. US 9,010,273 B2 11 12 7. The particulate animal litter composition of claim 1, 14. The particulate animal litter composition of claim 1, wherein said acidic material is selected from the group con wherein said litter composition release greater than 50% of sisting of citric acid, Zinc chloride and malic acid. hydrogen peroxide at pH of 6.3 or less. 8. The particulate animal litter composition of claim 7. 15. A method to the particulate animal litter composition of claim 1, comprising: 1) mixing an acidic material and least wherein said acidic material is citric acid. one alkaline earth metal peroxide; 2) pelleting said mixture; 9. The particulate animal litter composition of claim 1, 3) crushing then granulating said pellets to a particle size of wherein the amount of said peroxide used in said composition greater than 34 microns and less than 2400 microns; 4) blend is from 0.5 to 47.5 Wt. 9% of said litter composition. ingabalance of a liquid absorbing material with said granules 10. The particulate animal litter composition of claim 1, 10 to make up a total of 100 Wt.%. wherein said acidic material is present in the amount of from 16. The method of claim 15, wherein said composition 0.05 to 25 Wt.% of said litter composition. comprising 0.5 to 47.5 Wt. 9% of at least one alkaline earth metal peroxide and about 0.05 to 25 Wt. '% of an acidic 11. The particulate animal litter composition of claim 1, material. wherein said liquid absorbing material is present in the 17. The method of claim 15, wherein said at least one amount of from 50 to 95 Wt. 9% of said litter composition. 15 alkaline earth metal peroxide is selected from magnesium 12. The particulate animal litter composition of claim 1, peroxide and calciumperoxide, and said acid is selected from wherein said co-granules of at least one alkaline earth metal citric acid, malic acid and Zinc chloride. peroxide and said acidic material have a particle size of 18. The method of claim 15, wherein said liquid absorbing greater than 34 microns and Smaller than 2400 microns. material is selected from clumping and non-clumping clay. 13. The particulate animal litter composition of claim 1, 2O 19. The method of claim 15, wherein the ratio of said at wherein said co-granule has a ratio of said at least one alkaline least one alkaline earth metal peroxide to said acidic material earth metal peroxide to said acidic material of from 19:1 to is from 19:1 to 1:1. 1:1.