Clumping litter and method of making low track clumping litter

Abstract

A low tracking clumping litter is provided that has larger non-clumping litter particles with particle sizes sufficiently large enough relative to smaller clumping litter particles thereby disposing substantially all the smaller particles of litter in a litter box below the surface of the litter packing them into in voids between adjacent non-clumping particles. This reduces tracking because the surface is made up of the larger particles, which are not readily picked up by a cat, minimizing the number of smaller more readily hacked particles on top because they are packed in the voids. This causes urine to rapidly wet and swell the clumping particles happing the urine forming the clump on top. The litter has a hacking effectiveness of less than 90 particles / in2 and clumping particles preferably composed of extrusion modified starch-based water-soluble binder produce shed-resistant clumps having clump retention rates preferably greater than 97%.

Description

CLUMPING LITTER AND METHOD OF MAKING LOW TRACK CLUMPING LITTERCROSS REFERENCE

[0001] This application claims priority in and the benefit of U.S. Provisional Patent Application No. 63 / 465,916 filed May 12, 2023, the entire disclosure of which is hereby expressly incorporated herein by reference. This application also is a continuation-in-part of U.S. Patent Application No. 18 / 372,677, filed September 25, 2023, which claims priority in and the benefit of U.S. Provisional Patent Application No. 63 / 409,755 filed September 24, 2022, the entire disclosures of which are each hereby expressly incorporated herein by reference.FIELD

[0002] The present invention is directed to granular absorbents, preferably litter, for use by animals, and more particularly to clumping litter formulated to reduce tracking of the litter from a litterbox containing the litter by an animal using the litter.BACKGROUND

[0003] When a cat uses a litterbox containing litter composed of absorbent granules, it is common for a cat to undesirably track some of the litter granules out of the box when they leave the box. The process of litter being tracked out of the box by a cat typically occurs in a number of ways:

[0004] Entry and digging: As the cat enters the litter box, it may pick up litter particles that cling to its fur, especially if it has long hair. Because cats instinctively dig to bury their waste, and this action can cause litter particles to stick to their paws. During digging, cats might stir up the litter, causing some of it to scatter near the edge of the box or stick to their bodies.

[0005] Use of the litter box: After the cat has finished its business and buried its waste, it will often cover up the feces or urine by scraping more litter over it. This action is another opportunity for litter to adhere to the cat’s paws. Clumping litter, which is designed to absorb moisture and form clumps, tends to stick more readily to the paws than nonclumping varieties.

[0006] Exiting the litter box: As the cat exits the litter box, it may carry out litter particlesthat are stuck between its toes or clinging to its fur. The texture and length of the cat’s fur, as well as the moisture on its paws, can influence how much litter is carried out. Longer, denser fur can trap more litter.

[0007] Post litter box cleaning: Cats often engage in post-elimination grooming, licking their paws and fur. During this grooming, it is common for the cat to dislodge litter particles from their paws, which then fall onto the floor outside the litter box.

[0008] Movement around the house: As the cat moves around the house, any remaining litter particles on its paws or fur may be dislodged due to the cat’s movements. This leads to a trail of litter particles being spread around the area near the litter box, and potentially further, depending on the cat’s activities post-litter box use.

[0009] To mitigate this, many cat owners use a mat placed around the litterbox to catch some of the granules tracked by the cat that falls off the cat as it exits the box. Regular cleaning and maintenance of the litter box and surrounding area also help minimize the spread of litter outside the box. Despite the use of a mat to catch tracked litter and performing regular litter box cleaning and maintenance, it nonetheless is still very common for litter to be hacked by a cat beyond the mat that later falls off from the cat necessitating frequent cleanup by the cat owner.

[0010] In response, manufacturers of litter have hied to develop low hacking litter, albeit with limited success. One type of low hack or low tracking litter manufacturers have introduced is made of crystals of silica gel liber because the silica gel crystals are less likely to adhere to a cat’s fur and paws. Other low hack libers use granules or pellets that are larger and heavier than used in standard cat liber because they are less likely to get stuck in a cat’s paws or adhere to the cat’s fur.

[0011] U.S. Patent Application Publication No. US20050160997 discloses a cat and small animal liber composed of yellow pine wood fiber and a nonionic surfactant formed into pellets using a pellet mill which have a relatively large pellet diameters of between 4762 and 6350 microns (0.1875 inches to 0.250 inches). While the ‘997 publication discloses pellets having these large pellet diameters “can be retained whole to limit tracking by the animal from the liber pan”, it teaches that use of whole pellets may not be comfortablefor the animal by further disclosing that the pellets “may be crumbled and screened for a [softer] texture and thus greater animal comfort.”

[0012] Attempts to make a clumping litter that tracks less have proven more challenging because granules of a clumping material, such as granules of sodium bentonite or another clumping material, tend to be sticky in nature which causes them to more readily adhere not only to a cat’s paws but to their fur as well.

[0013] One example of a clumping animal litter intended to reduce tracking is disclosed in U.S. Patent No. 11,918,969 is made of composite litter particles composed of sodium bentonite and activated carbon having a particle size distribution of 16 / 50 mesh ranging from 300 to 1180 microns in size. The litter purports to reduce tracking by eliminating nearly all the fine particles, commonly referred to as “fines”, in the litter which would pass through a size 100 mesh (e.g., 0.150 mm or 150 pm sieve opening) by limiting the amount of fines in the litter to no more than about 10%, about 5%, about 4%, about 3%, about 2.5%, about 2%, about 1.5%, or about 1% of the litter. However, despite significantly reducing and even nearly eliminating fines from the litter, tracking will still nonetheless occur with this litter due to the relatively small size of the composite litter particles that actually make up the litter.

[0014] U.S. Patent No. 8,720,375 discloses another clumping litter formulated to reduce tracking that is composed of particles of a clay-based liquid-absorbing material, such as sodium bentonite, and particles of at least one filler consisting of a non-absorbent, nonsoluble substrate coated with at least one clumping agent, which can also be sodium bentonite. The particles of clay-based liquid-absorbing material has a particle size of between 500 and 2000 microns (between 0.50 and 2.00 mm), preferably between 400 and 1600 microns (between 0.4 and 1.6 mm), and more preferably between 400 and 1200 microns (between 0.4 and 1.2 mm). The particles of clay-based liquid-absorbing material make up between 40% and 99%, preferably between 50% and 95%, and more preferably between 40% and 85%, by weight of the litter. The clay-based liquid-absorbing material is selected from clumping and non-clumping clay materials or a mixture of clumping and nonclumping clay materials. The filler has a particle size of between 250 and 850 microns(between 0.25 and 0.85 mm) and makes up between 10% and 60%, preferably 30% and 60%, and more preferably 45% and 60% by weight of the litter. The clumping agent can be a clumping clay, e.g., sodium bentonite, a polysaccharide, a water-soluble gum, a dry particulate cellulose ether, a water absorbent polymer, or a mixture thereof. The clumping agent is present in an amount between 0.1% and 20%, preferably 0.25% and 10%, and more preferably 0.45% and 7.0% by weight of the litter. However, tracking will also still occur with this litter due to the relatively small size of the litter particles that make up the litter.

[0015] In addition, because most clumping litters, including the above purported reduced tracking clumping litters, predominantly use sodium bentonite to clump, the sodium bentonite swells upon absorbing urine during clumping and forms a clump that shrinks when it dries. Unfortunately, sodium bentonite lacks the plasticity to prevent tensile and compressive stresses that build up in the clump during drying and shrinking that can cause cracks to form in the dried clump. The formation of such cracks in the dried clump can cause the clump to crumble or even collapse as it is being scooped out of the litter box in turn causing the clump to shed fragments of spent litter that fall from the clump back into the litter. Such shedding is undesirable because it can cause contamination of the litter requiring more frequent litter box cleaning and lead to more rapid depletion of the litter. It can also cause the litter to become undesirably odorous because the shed portions of the clump that are returned to the litter box can harbor odor-causing bacteria as well as other bacteria which can be deleterious to a cat’s health. This can even lead to the cat eliminating outside the litter box.

[0016] What is needed is an improved clumping litter formulation which minimizes tracking while still clumping well. What is also needed is a low tracking clumping litter formulation that produces clumps that shed less or not at all when being removed from the litter box.SUMMARYThe present invention is directed to a low tracking clumping litter formulation having larger non-clumping litter particles with particle sizes sufficiently large enough relative to smaller clumping litter particles thereby disposing substantially all the smaller particles of litter in a litter box below the surface of the litter packing them into in voids betweenadjacent non-clumping particles. This reduces tracking because the surface is made up of the larger particles, which are not readily picked up by a cat, minimizing the number of smaller more readily tracked particles on top because they are packed in the voids. This causes urine to rapidly wet and swell the clumping particles trapping the urine forming the clump on top. The litter has a tracking effectiveness of less than 90 particles / in2and clumping particles preferably composed of extrusion modified starch-based water-soluble binder produce shedresistant clumps having clump retention rates preferably greater than 97%.DRAWING DESCRIPTION

[0017] One or more preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout and in which:

[0018] Figure 1 is a fragmentary cross-section elevation view of clumping particles and nonclumping particles of a low hacking clumping litter of the invention in a litter box depicting packing of the smaller clumping particles in between adjacent larger non-clumping particles improving clumping while minimizing the number of smaller clumping particles on the surface of the litter that can be hacked out of the box;

[0019] Figure 2 is a top view of another preferred low hacking litter that is a dual component litter having a pair of different types of clumping and non-clumping particles where the sizes of both types of clumping particles are smaller than the sizes of both types of non-clumping particles for reducing hacking;

[0020] Figure 3 is a front elevation view of a litter particle hacking effectiveness tool used to assess hacking effectiveness of liber;

[0021] Figure 4 is a rear elevation view of the liber particle hacking effectiveness tool of Figure 3;

[0022] Figure 5 presents Table 1, which is a table sehing forth the liber particle material type, particle size ranges by sieve size, the bulk density, and the respective formulations in weight percentages of low tracking liber trial formulation nos. 1-6;

[0023] Figure 6 presents Table 2, which is a table providing the particle size breakdowns and weight percentages for preferred non-clumping and non-clumping liber particleconstituents as well as for low tracking litter trial formulation nos. 1-6;

[0024] Figure 7 presents Table 3, which is a table providing the density, pre-drop clump weights, post-drop clump weights when dropped at 10 minutes and 30 minutes along with the corresponding clump retention rates for low tracking litter trial formulation nos. 1-6; and

[0025] Figure 8, presents Table 4, which is a table providing the litter particle tracking effectiveness test results in numbers of particles per square inch for low tracking litter trial formulation nos. 1-6 and four commercially available litters for comparisons sake.

[0026] Before explaining one or more embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description and figures. The invention is capable of other embodiments or being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.DETAILED DESCRIPTIONINTRODUCTION

[0027] Cat litter is manufactured to either be a clumping litter which forms clumps when exposed to urine or another aqueous liquid, e.g., water, that wets particles of the clumping litter, or a non-clumping litter which does not clump when its particles are wetted with urine or another aqueous liquid.

[0028] Non-clumping litters are typically formulated with larger sized litter particles, typically larger than 2 millimeters or 2000 microns (sieve 10) in size, so when poured into a litter box voids form between adjacent litter particles that are large enough in size and number to define channels or passages in the litter so urine can relatively rapidly traverse downwardly through them towards the bottom of the box when a cat uses the litter. The use of such large sized particles results in relatively loose packing of the litter in the box producing relatively large voids between adjacent particles that desirably prevent urine from pooling and making a gooey mess on top of the litter.

[0029] The relatively large sized particles used in non-clumping litter tend to reduce tracking as they are less likely to be carried out of the litter box. This is because these larger sizedparticles are large enough so as not to become easily embedded in the paws of a cat using the litter. And because these larger particles are heavier, they also tend not to be readily picked up by the fur of the cat during use of the litter.

[0030] Clumping litter is typically formulated with smaller sized litter particles in comparison to non-clumping litter. Smaller sized litter particles are needed during clumping to block the passages or channels intentionally provided in non-clumping litter that would ordinarily allow urine to traverse downwardly through the litter towards the bottom of the litter box. The use of smaller sized particles in clumping litter relatively tightly packs them together in the box reducing the size of the voids between adjacent particles so they are quickly plugged by rapidly swelling clumping litter particles contacting the urine trapping the urine at or near the surface of the litter. Trapping the urine at or near the litter’s surface ensures that the urine is absorbed by litter at or near the litter’s surface and forms a clump on top of the surface of the litter that can easily be scooped out of the litter.

[0031] When a cat urinates, it typically is at a rate of about 1 milliliter of urine per second. Because the use of smaller litter particles traps the urine at or near the litter’s surface, it causes clumping material of the clumping particles to become sufficiently wetted with urine to activate the clumping material causing an expanding ball-like clump to form. During activation, the clumping material of each wetted clumping particle swells and becomes sticky causing it to adhere to one or more adjacent litter particles clumping them together. The urine becomes absorbed by the particles that form the clump locking up the urine in the clump and preventing it from flowing downwardly towards the bottom of the box.

[0032] This must occur nearly instantaneously when the urine makes contact with the litter, otherwise the urine will flow downwardly towards the bottom of the litter box, resulting in a gooey mess at the bottom of the box. To facilitate clumping and obstruct the urine from flowing to the bottom, the smaller particles used in clumping litter include clumping particles whose clumping material expands immediately upon wetting to plug the voids between particles. Through plugging of the voids, it prevents the urine from flowing downwardly and redirects urine flow so it remains at or near the top of the litter where itwets more and more clumping particles at or near the top of the litter forming an everexpanding ball-like clump on top of the litter that enables it to be easily scooped out.

[0033] Generally, manufacturers of clumping cat litters have created litters with particle sizes less than 3350 microns (3.35 mm or 0.132 inches) (see e.g., Hughes, U.S. Patent No. 5,000, 115) and in others having particle sizes less than 2000 microns (2.0 mm or 0.079 inches) (see, e.g., Kuras, U.S. Patent No. 11,026,397). Both Hughes and Kuras teach the use of components with a preponderance of sizes less than 3500 microns (3.5 mm or 0.138 inches) and both also used clumping and non-clumping components of similar small sizes. Among other things, these patents teach the use of a pre-mixture surface area proxy associated with components having similar particles sizes and assumptions of similar shapes. Most prior art clumping litters used products of similar size distributions for the components they blend to improve consistency of clumping and ease of blending. Traditionally, attempts at making clumping litter having large particles led to a litter that clumped inconsistently, and thus was not commercially viable.

[0034] Clumping litter formulations often include clumping agents, absorbent materials, non-absorbent components, and often also include non-clumping components. Clumping agents generally include, but are not limited to, sodium bentonite which is a water absorbing swelling clay that can absorb up to six times its weight in water, gums, carboxymethyl cellulose, acrylics, and / or high pressure extruded grains. Absorbent components of litter generally include, but are not limited to, calcium bentonite, starches, walnut shells, paper, products containing cellulose and perlite. Non-absorbent components include sand as well as a variety of other types of non-absorbent products. Some clumping agents are plated or coated onto other particles - for example, sodium bentonite onto perlite or guar gum onto distiller dried grains or guar gum onto cellulose products.

[0035] While the above-described clumping litters enable clumps to be formed in the litter when exposed to urine that can easily be removed, the smaller sized particles used in clumping litter results in increased tracking of the litter outside of the litterbox. Improvements to clumping litters are therefore desirable.

[0036] It would thus be advantageous to have clumping litter formulations having very low tracking characteristics without sacrificing clumping ability, clumping efficiency, clump integrity. It is also desirable to have a clumping litter that not only is low tracking but which also minimizes the amount of spent litter particles that are shed from the clump while the clump is being removed from the litter box.Low TRACKING REDUCED SHEDDING CLUMPING CAT LITTER

[0037] Figure 1 illustrates a low tracking clumping litter 40 of the present invention that is a dry blend of at least a plurality of pairs of, i.e., at least three, clumping litter particles 42 of a single type of clumping material 44 that can be and preferably is water absorbent, and at least a plurality of pairs of non-clumping litter particles 46 of a single type of non-clumping material 48 that can also be water-absorbent. The litter 40 is formulated such that the clumping litter particles 42 are sufficiently smaller than the non-clumping particles 46 configuring the litter 40 so that when the litter 40 is disposed in a litter box 50, substantially all of the smaller clumping particles 42 are distributed below the litter’s surface 52 and packed in between adjacent larger sized non-clumping particles 46 reducing tracking by minimizing the number of smaller particles 42 that are on the surface 52 that can be picked up by a cat using the litter 40. The litter box 50 is shown in phantom in Figure 1 holding the litter 40 in box 50. Box 50 has a bottom wall 54 underlying the litter 40 from which a plurality of pairs of sidewalls generally vertically extends with only a portion of one sidewall 56 shown in Figure 1 that is depicted as being disposed in contact with at least a plurality of clumping and non-clumping particles 42, 46 of the litter 40.

[0038] This litter particle size formulation advantageously configures the litter 40 to minimize tracking by forming a top surface 52 of litter 40 poured into the litter box 50 that is composed substantially completely of larger sized particles 46, which are less readily picked up by a cat’s paw(s) during use of the litter 40 by a cat, thereby beneficially minimizing the number of smaller sized particles 42 disposed on or along the top surface 52 of the litter 40 as these smaller sized particles 42 are more easily picked up by a cat’s paw(s) during litter use. This non-clumping and clumping litter particle formulation of low tracking litter 40 the present invention advantageously configures the litter 40 so the largerlitter particles of the litter 40 are non-clumping litter particles 46, as they are less sticky than the clumping particles 42 and are therefore even less likely to adhere to a cat’s paw(s) during use of the box 50 by a cat compared to the smaller stickier clumping particles 42 of the litter 40.

[0039] Formulations of a low tracking litter 40 of the present invention have or are configured to have a litter tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch when tested in accordance with the litter particle tracking effectiveness test described in more detail herein. Such formulations of low tracking litter 40 of the present invention advantageously also possess reduced shedding during removal of a clump formed of litter particles 42, 46 from litter 40 in a litter box 52 preferably by having or being configured to have a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% tested in accordance with the clump retention rate test procedure set forth in more detail below. Clumps formed from such formulations of low tracking litter 40 of the present invention preferably also have or are also configured to have a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch where the clump being clump compression strength tested is tested in accordance with the clump compression strength test procedure set forth in more detail below.

[0040] With reference to Figures 3 and 4, a preferred litter tracking effectiveness test tool 60 employs a generally flat or planar litter tracking effectiveness test pad 61 with a fibrous face 62 facing in one direction and a handle 63 on the other side extending in the opposite direction. The pad 61 preferably has a fibrous face 62 that is a flocked fiber pad face composed of uprightly extending litter particle pickup fibers 64 and which includes a generally, rectangular, e.g., square, litter particle tracking pickup pad region 66 shown in black in Figure 3 that preferably is one inch by one inch square. If desired, the tool 60 can be made to have the fibrous face 62 of the pad 61 to be limited to be one inch by one inch square.

[0041] With reference to Figure 4, the pad 61 preferably is about a quarter inch thick and includes a base 68 from which the fibers 64 outwardly extend with the base 68 supported by or on an underlying rigid backing 70 shown in Figure 4 that can be made of a polystyrene foam, e.g., STYROFOAM, or the like from which the handle 62 outwardly extends. If desired, a layer of foam, such as a layer of an open cell foam can be disposed between the fibers 64 and the backing 70. The pad 61 is about one quarter inch thick and the fibers 64 are made of a synthetic material, preferably nylon, having a fiber length of about 0.150 inches such that the fibers 64 stick out from the base 68 about 0.150 inches.

[0042] In carrying out a litter P acking effectiveness test, the handle of the tool is manually grasped by a user, e.g., tester, and maneuvered so the fibrous face of the pad overlies the surface 52 of the litter 40 before being pressed straight down, and not at an angle, against and preferably at least slightly into the litter 40. 0.5 pounds per square inch of pressure is applied in pressing the fibrous face of the pad against the litter 40 at the surface 52 for five seconds. Thereafter, the tool 60 is lifted straight up away from the surface 52 and out of the litter 40. The number of litter particles 42 and / or 46 which adhere to the one inch by one inch test region of the pad are counted and preferably removed to obtain a count of the number of particles per square inch, which is the litter particle tracking effectiveness. The litter Packing test procedure can be and preferably is repeated at three other different locations of the outer surface 52 of the liber 40. The total number of liber particles 42 and / or 46 picked up by the one inch by one inch square test pad region are counted and divided by the number of test procedures performed to get an average liber particle hacking effectiveness that enables the uniformity of the blend or formulation of the liber to be assessed. In a preferred embodiment, the tool 60 is a 1500C HANDI PAINTR made and sold by Shur-Line of Waukesha Wisconsin but a Shur-Line 1520C Trim and Touch Up Pad can also be used.

[0043] Suitable clumping materials from or of which the clumping particles 42 are at least partially or completely composed or made include a clumping clay, such as preferably sodium bentonite; a starch, starch-containing material, and / or a starch-derived material, such as preferably a starch-containing cereal grain or legume, extruded under a high enoughpressure and temperature to cause at least some of the starch therein to be modified, e.g., physically, thermally, and / or chemically modified, so as to form a water-soluble binder that is a litter clumping agent in an amount sufficient for litter clumping to occur during use of the litter 40 by a cat; other starch-based clumping agents; cassava; tapioca; a gum or gumbased clumping agent, such as gum arabic, gum karaya, gum tragacanth, gum ghatti, guar gum, locust bean gum, and xanthan gum; an alginate, such as sodium alginate; a carrageenan, such as Kappa-carrageenan; a pectin, such as high methoxyl pectin (HMP), low methoxyl pectin (LMP) or amidated low methoxyl pectin; dextran, such as a high molecular weight dextran, a low molecular weight dextran, or a cross-linked dextran; gelatin; gluten; vinyl polymers, including polyvinyl alcohol, polyvinyl esters such as polyvinyl acetate, polyvinylpyrrolidone, polyvinyloxazolidone, polyvinylmethyloxazolidone, copolymers or mixtures thereof; semisynthetic polymers, including guar gum derivatives and cellulose ethers, such as methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylhydroxyethyl cellulose, methylhydroxypropyl cellulose, carboxymethylcellulose, preferably hydroxypropylmethylcellulose or mixtures thereof; and superabsorbent polymers capable of use as a litter clumping material.

[0044] Suitable non-clumping materials from or of which the non-clumping particles 46 are at least partially or completely composed or made include a non-clumping absorbent smectite, such as calcium bentonite, attapulgite, Fullers Earth, sepiolite and / or kaolinite; plastic; rubber, e.g., comminuted scrap tires; glass, e.g., glass beads, granules or pellets preferably having a smooth exterior or texture; wood, including wood pellets, sawdust, sawdust pellets, wood shavings, bark, comminuted wood particles, including granules, pellets or balls made at least in part of wood, or the like; paper, e.g., granules, pellets, or balls composed at least in part of paper; sand, e.g., silica sand; perlite; plant shells or hulls, such as comminuted shells or hulls, e.g., ground shells or hulls, from walnuts, e.g., walnut shells, hazelnuts, e.g., hazelnut shells, cashews, e.g., cashew shells, almonds, e.g., almond shells, macadamia nuts, e.g., macadamia nut shells, peanuts, e.g., peanut shells or outer hulls from peanuts, Brazil nuts, e.g., Brazil nut shells, pine nuts, e.g., pine nut shells or outer hulls, and / or pecans, e.g., pecan shells or hulls.

[0045] In one preferred low tracking litter embodiment and formulation, the clumping litter particles 42 are clumping litter pellets extruded by an extruder, preferably a single screw extruder, from a starch-containing material, preferably a starch-containing admixture having a moisture content no greater than 22%, preferably no greater than 20%, more preferably no greater than 18%, and which contains at least 40% starch, preferably at least 50% starch, more preferably at least 60% starch by admixture weight, at an extrusion pressure of at least 2000 pounds per square inch, preferably at least 2500 pounds per square inch, more preferably at least 3000 pounds per square inch, at an extrusion temperature of at least 100° C, preferably at least 120° C, more preferably at least 135° C, that modifies, preferably extrusion modifies, at least some of the starch in the admixture, such as by physical modification and / or thermal modification, through application of the extrusion pressure while the admixture is in the extruder, into a water soluble binder, preferably cold water soluble binder, which is a clumping agent, in an amount of at least 5%, preferably at least 10%, and more preferably at least 15%, by pellet weight in each clumping litter pellet extruded from the extruder. The starch-containing admixture preferably is composed of one or more cereal grains, such as wheat, com, oats, rice, barley, sorghum, and / or millet; one or more tubers, e.g., yams, sweet potatoes, and / or another type of potato; and / or one or more legumes, such as lentils, chickpeas, peas, lupins, and beans, such as butter beans, haricot (navy) beans, cannellini beans, red kidney beans, adzuki beans, black-eyed beans and / or soybeans. The clumping litter particles 42 can be extruded clumping litter pellets, such as the extruded clumping litter pellets of a clumping lightweight natural grass litter marketed and sold by Pioneer Pet Products, LLC of Cedarburg Wisconsin as SmartCat All Natural 100% Grass Lightweight Clumping Litter that can be grey in color, having a composition, construction, configuration and / or made using a method of manufacture substantially the same as or like the extruded clumping litter pellets disclosed in one or more of commonly owned U.S. Patent Nos. 11013211, 11083168, and 11457605 the entirety of each of which is expressly incorporated herein by reference. Where extruded clumping litter pellets are used as clumping litter particles 42 in a low tracking litter 40 of the present invention, the clumping material 44 of each extraded pellet is or includes starch-based extrudate from theaforementioned starch-containing admixture extruded by the extruder during pellet extrusion that contains the at least 5%, preferably at least 10% and more preferably at least 15% water soluble binder, preferably cold water soluble binder, formed of the aforementioned extrusion-modified starch modified by and / or during litter pellet extrusion that at least partially solubilizes into one or both a gel and / or flowable adhesive when the pellets are wetted with an aqueous liquid, preferably urine, one or both of which is a clumping agent that causes adjacent wetted pellets to agglomerate and adhere to one another forming a scoopable clump. In at least one such preferred embodiment, the non-clumping litter particles 46 can be and preferably composed of one or more of the aforementioned non-clumping materials, such as preferably calcium bentonite, comminuted, e.g., ground, walnut shells, sand, paper granules, non-clumping particles composed of wood, cellulosic particles or granules, or another one of the aforementioned non-clumping materials.

[0046] It is also contemplated as being within the scope of the low tracking litter 40 of the present invention, to use extruded starch-based water-soluble binder containing clumping material 44, preferably extruded starch-based clumping material 44, such as made of extruded clumping pellet fines, e.g., finely sized extrudate particles, and / or comminuted extruded clumping pellets, as clumping material 44 that is applied, such as by coating or plating, onto the outer surface(s) of substrate particles, such as disclosed in commonly owned co-pending U.S. Application No. 18 / 372,677, filed September 25, 2023, the entirety of which is expressly incorporated herein by reference, thereby forming them into clumping particles 42 for use with or in the litter 40. The substrate particles can be a clumping substrate particle, e.g., composed of a clumping material such as sodium bentonite, a nonclumping substrate particle, e.g., composed of a non-clumping material like calcium bentonite, a non-absorbent substrate particle, e.g., composed of a non-absorbent material such as of plastic, glass, rubber or metal, an absorbent substrate particle, e.g., composed of a water-absorbent material such as perlite or a clay like sodium bentonite and / or calcium bentonite, an inorganic substrate particle, e.g., composed of an inorganic material, a synthetic substrate particle, e.g., composed of a synthetic, e.g., polymeric, material, and / or an organic substrate particle, e.g., composed of an organic material, preferably coated withextruded starch-based clumping material 44 to form clumping particles 42 preferably having the particle sizes, particle size range(s), and / or particle size distribution(s) disclosed elsewhere herein. In at least one preferred embodiment of a low tracking litter 40 made with clumping particles 42 composed of such substrate particles coated or plated with extruded starch-based clumping material 44, the non-clumping litter particles 46 of the litter 40 can be and preferably are composed of at least one of the aforementioned non-clumping materials, such as preferably calcium bentonite granules, comminuted, e.g., ground, walnut shells, sand, perlite, paper granules, non-clumping particles composed of wood, cellulosic particles or granules, or particles, e.g., granules, of another one of the aforementioned nonclumping materials.SINGLE CLUMPING AND NON-CLUMPING COMPONENT LOW TRACKING LITTER

[0047] In one preferred embodiment, the litter 40 is formulated so that the particle size of the largest sized clumping litter particles 42 is at least 40%, preferably at least 45%, and more preferably at least about 50% of the particle size of the smallest sized non-clumping litter particle(s) 46 such that the low tracking litter 40 of the present invention has and / or configuring the litter 40 to have a desirably low tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch. In one such embodiment the litter 40 is formulated such that the size of the largest sized clumping litter particles 42 is between about 40% and about 60% of the size of the smallest size non-clumping litter particles 46 thereby configuring the litter 40 to have a desirably low tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch. Such litter formulations preferably also form litter clumps during use of the litter 40 by a cat configured to reduce shedding during scooping by the clumps having (a) a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% and / or (b) a clump compression strength of at least 40 pounds per square inch, preferably at least 60pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.CLUMP COMPRESSION STRENGTH TEST PROCEDURE

[0048] The following equipment was utilized in carrying out extruded granular absorbent (litter) clump compression strength testing:

[0049] (l) 15 mL centrifuge tubes with screw top caps, plastic

[0050] (2) 3.0 mL disposable pipettes, plastic

[0051] (3) Distilled water

[0052] (4) Force Gauge: Mark-10 Model M7-500 S / N 3674412[0053J(5) Motorized test stand: Model ESM303 S / N 3979431

[0054] (6) Digital control panel: Mark- 10 Model DC4060 S / N 3680222

[0055] (7) DREMEL hand held high speed rotary power tool with deep cutting wheel

[0056] (8) Samples of extruded granular absorbent material (extruded pellets) to be wetted to form clumps therefrom to be compression strength tested.

[0057] Using the above, the following methodology was utilized in performing extruded granular absorbent (litter) clump compressive strength testing:

[0058] ( 1) Saw off tapered end of a 15 mL test tube, and clean off burrs.

[0059] (2) Screw on cap of test tube and fill tube with sample material to be tested.

[0060] (3) Add distilled water to sample material in test tube (1 : 1 by weight) to wet sample material

[0061] (4) Wait 10 seconds

[0062] (5) Unscrew cap from test tube and gently push “cast” clump formed of wetted sample material out of test tube using bulbous end of a plastic pipette (snug fit).

[0063] (6) Let cast clump sit and dry for 5 days at ambient room temperature conditions.

[0064] (7) Using deep cutting wheel attached to a DREMEL high speed rotary tool at high speed greater than 10,000 RPM, cut cast clump into barrel-shaped sections each approximately 0.5 inches thick or long.

[0065] (8) Measure the diameter and length of each barrel shaped cast clump section.

[0066] (9) Place barrel shaped (cylindrical) cast clump section on middle of compression test stand platform, with flat cut ends of barrel shaped cast clump section on top and bottom for compression testing by force gauge.

[0067] (l 0) Using a compression speed of 0.5 inches / minute, determine peak compression strength of barrel shaped cast clump section using force gauge.CLUMP RETENTION RATE TEST PROCEDURE (CLUMP DROP TEST)

[0068] The clump retention rate is determined by adding 10 milliliters of water to the litter 40 to wet the pellets 42 and 46 and form a clump in the litter. After awaiting a predetermined period of time, that in one set of tests is ten minutes and another set of tests is thirty minutes, the clump is removed from the litter, weighed and then dropped from a height of 18 inches onto a number 10 screen. The clump that remains after being dropped onto the screen is weighed with the clump retention rate being the decimal result of the postdrop clump weight divided by the pre-drop clump rate multiplied by 100 to obtain the percentage of the clump that is left that is the clump retention rate (expressed as a percentage).

[0069] In such a preferred embodiment, the smallest size non-clumping litter particles 46 of the litter 40 have a particle size of at least 3000 microns, preferably at least 3250 microns, and more preferably at least about 3350 microns and the largest size clumping litter particles 42 have a particle size no greater than 2000 microns, preferably no greater than 1850 microns, and more preferably no greater than about 1700 microns. This minimum limit on the size of the non-clumping particles 46 and maximum limit on the size of the clumping particles 42, as indicated by the relationship defined by the aforementioned minimum percentages and / or percentage ranges in the preceding paragraph above, is critical to ensuring that the maximum size of the clumping particles 42 is small enough relative to the minimum size of the larger-sized non-clumping particles 46 so that substantially all of the smaller clumping particles 42 are distributed below the litter’s top surface 52, preferably relatively uniformly distributed, when the litter 40 is poured into the litter box 50 packing the voids between the non-clumping particles 46 that would ordinarily define channels through which the urine would flow downwardly away from the surface 52. By ensuring that the clumping particles 42 are distributed below the top surface 52 of the litter 40, particularly disposing them in the voids between adjacent non-clumping particles 46 that can form downward channels in the litter 40, the clumping particles 42 in the voids belowbut adjacent the surface 52 will become rapidly wetted by urine and swell plugging the voids between adjacent non-clumping particles 46 before the urine can flow downwardly in the channels defined by the voids toward the bottom 56 of the litter box 50. This ensures that the urine will be trapped at or near the litter’s surface 52 rapidly activating the clumping material 44 in the clumping particles 42 quickly forming an expanding ball-like clump of wetted clumping particles 42 and non-clumping particles 46 of the litter 40 at or near the surface 52 that can be easily scooped out.

[0070] As a result of there being a minimum of the relatively small clumping particles 42 disposed on and along the top surface 52 of the litter 40 it results in a greater more optimal amount of the clumping particles 42 being disposed below the non-clumping particles 46 and between adjacent non-clumping particles 46, helping to ensure that the litter 40 of the present invention is not only low tracking but also produces clumps having a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% that minimizes and preferably substantially completely prevents shedding during clump removal. As a further result of there being a minimum of the relatively small clumping particles 42 disposed on and along the top surface 52 of the litter 40 that results in a greater more optimal amount of the clumping particles 42 being disposed below the non-clumping particles 46 and between adjacent non-clumping particles 46, the low tracking litter 40 of the present invention produces clumps that preferably also has a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch that minimizes and preferably substantially completely prevents shedding during clump removal.

[0071] In at least one of the aforementioned preferred embodiments, the low tracking litter 40 has clumping particles 42 composed of (1) extruded starch-based clumping pellets containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion- modified starch-based water soluble binder, and / or (2) substrate particles coated or plated with extruded starch-based clumping material 44 containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binderthat absorb at least five and preferably at least six times the weight of the extruded starch- based clumping material of the pellet or particle in urine or water and which advantageously more rapidly swell when wetted with urine more quickly plugging voids between adjacent non-clumping particles 46 trapping urine at or near the top surface 52 of the litter 40 more speedily activating the water soluble binder of each wetted pellet’s or particle’s extruded starch based clumping material advantageously rapidly forming a litter clump on the top surface 52 of the litter 40. The use of clumping particles 42 composed of (1) extruded starch-based clumping pellets containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binder, and / or (2) substrate particles coated or plated with extruded starch-based clumping material 44 containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion- modified starch-based water soluble binder advantageously forms shedding-resistant clumps that are harder, stronger and which do not crack, crumble, compress or otherwise shed by having a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% and a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch when tested in accordance with the corresponding clump retention rate and clump compression strength test procedures set forth below.

[0072] Preferred formulations of low tracking litter 40 in accordance with the present invention can be and preferably are further formulated to configure the litter 40 so that the smallest size of the clumping particles 42 ranges between about 4% and about 10% of the smallest size of the non-clumping particles 46 helping ensure that the size of the smallest clumping particles 42 is large enough relative to the smallest non-clumping particles 46 to minimize the number of clumping particles 42 that become attached on top of non-clumping particles 46 on the surface 50 of the litter 40 advantageously resulting in even the smallest clumping particles 42 being distributed below the litter’s surface 50. This also reduces tracking resulting in the litter 40 having a tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and morepreferably no greater than about 60 particles per square inch. Such preferred litter formulations preferably form clumps having a retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% that minimize and preferably substantially completely prevent shedding during removal. Such preferred litter formulations can and preferably also forms clumps having a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch and which are shed-resistant.

[0073] In such preferred litter formulations, the smallest sized clumping particles 42 preferably have a minimum particle size of at least 200 microns and preferably of at least about 250 microns including to ensure that even the smallest of the clumping particles 42 are large enough to avoid being or becoming dust. In at least one such preferred litter formulation, the smallest sized clumping particles 42 can have a minimum particle size of at least or about 500 microns. As previously noted, in such preferred formulations, the smallest size non-clumping litter particles 46 of the litter 40 have a minimum particle size of at least 3000 microns, preferably of at least 3250 microns, and more preferably of at least about 3350 microns. The relationship between the smallest sized non-clumping particles 46 and the smallest sized clumping particles 42 defined by the aforementioned minimum percentage(s) in the preceding paragraph is critical to ensuring that the smallest sized clumping particles 42 are not too small relative to the smallest of the larger-sized nonclumping particles 46 so that the smallest sized clumping particles 42 do not become nor behave as dust and also ensure they are large enough to be distributed below the litter’s top surface 52 when the litter 40 is poured into the litter box 50 packing the voids between nonclumping particles 46 that would ordinarily form channels through which the urine would flow unrestrictedly downwardly away from the litter’s surface 52. By ensuring that even the smallest sized clumping particles 42 are large enough to be distributed below the top surface 52 of the litter 40 and fill in the voids that form downward channels between adjacent nonclumping particles 46 when the litter 40 is poured into the litter box 50, it minimizes the number or amount of the smaller clumping particles 42 which end up carried by or disposedon non-clumping particles 42 on the surface 52 of the litter 40 thereby reducing, minimizing, and preferably substantially completely preventing tracking. By ensuring that even the smallest sized clumping particles 42 are large enough to cause them to be distributed below the litter’s surface 52 and fill in the voids between and underneath adjacent non-clumping particles 46, it ensures that even the smallest sized clumping particles 42 will become rapidly wetted by urine from a cat using the litter 40 and swell, plugging the voids between adjacent non-clumping particles 46, trapping the urine at or adjacent the litter’s surface 52, and activating the clumping material 44 of the clumping particles 42 to quickly form a clump of the litter 42 on or adjacent the surface 52.

[0074] In another preferred embodiment, the litter 40 is formulated so that (a) the size of the largest size clumping litter particles is at least 40%, preferably at least 45%, and more preferably at least about 50% smaller than the size of the smallest size non-clumping litter particles, and (b) the size of the smallest size clumping particle is between about 4% and about 10% of the size of the smallest size non-clumping particle configuring the litter 40 to be a low tracking litter of the present invention having a tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch and preferably also forms clumps with reduced shedding that have a retention rate of at least 90%, preferably at least 95%, and more preferably at least 97%. Such low shedding clumps can and preferably also does have a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.

[0075] In at least one of the aforementioned preferred embodiments, the low hacking liber 40 has clumping particles 42 composed of (1) extruded starch-based clumping pellets containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion- modified starch-based water soluble binder, and / or (2) substrate particles coated or plated with extruded starch-based clumping material 44 containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binder that absorb at least five and preferably at least six times the weight of the extruded starch-based clumping material of the pellet or particle in urine or water and which advantageously more rapidly swell when wetted with urine more quickly plugging voids between adjacent non-clumping particles 46 trapping urine at or near the top surface 52 of the litter 40 more speedily activating the water soluble binder of each wetted pellet’s or particle’s extruded starch based clumping material advantageously rapidly forming a litter clump on the top surface 52 of the litter 40. The use of clumping particles 42 composed of (1) extruded starch-based clumping pellets containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binder, and / or (2) substrate particles coated or plated with extruded starch-based clumping material 44 containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion- modified starch-based water soluble binder advantageously forms shedding-resistant clumps that are harder, stronger and which do not crack, crumble, compress or otherwise shed when being scooped out of the top surface 52 of the litter 40. Such shedding-resistant clumps preferably have a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% and a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.

[0076] In still another preferred embodiment, the litter 40 is formulated so that the particle size of the largest size clumping particles 42 ranges between 30% and 50%, preferably between about 35% and about 45% of the size of the largest size non-clumping litter particles 46 to ensure that even the largest sized clumping particles 42 are sufficiently smaller than the largest sized non-clumping particles 46 to cause the clumping particle 42 to distribute themselves between and below adjacent non-clumping particles 46 far enough below the surface 50 of the litter 40 that the clumping particles 42 cannot be picked up by a paw of a cat stepping on the surface 50 of the litter 40 during use of the litter box 50. This in turn ensures that the litter 40 has or is configured to have a tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch. This embodiment preferably also produces litter clumps having a retention rate of at least 90%,preferably at least 95%, and more preferably at least 97% which advantageously possess reduced shedding. This embodiment can and preferably also does produce clumps having a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch. The largest size clumping particles have a size that is no larger than 2000 microns, preferably no larger than 1800 microns, and more preferably no larger than about 1700 microns. The largest sized non-clumping particles 46 have a size that is no greater than 5000 microns, preferably no greater than 4850 microns, and preferably no greater than about 4750 microns.

[0077] In yet another preferred embodiment, the litter 40 is formulated so that the size of the smallest sized clumping particles 42 is between 4% and 15%, preferably between about 4% and about 10% of the size of the largest sized non-clumping litter particles 46 producing a low tracking litter 40 having and / or configuring the litter 40 to have a tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch. The largest sized non-clumping particles 46 have a size that is no greater than 5000 microns, preferably no greater than 4850 microns, and preferably no greater than about 4750 microns. Such a litter 40 preferably forms reduced-shedding clumps that have a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97%. These clumps can have and preferably also do have a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.

[0078] The smallest size clumping particles have a size that is no smaller than 200 microns, preferably smaller than 250 microns, and more preferably no smaller than about 500 microns. The largest sized non-clumping particles 46 have a size that is no greater than 5000 microns, preferably no greater than 4850 microns, and preferably no greater than about 4750 microns.

[0079] In yet still another preferred embodiment, the litter 40 is formulated so that (a) the particle size of the largest sized clumping particles 42 ranges between ranges between 30%and 50%, preferably between about 35% and about 45% of the size of the largest size nonclumping litter particles 46, and (b) the size of the smallest sized clumping particles 42 ranges between 4% and 15%, preferably between about 4% and about 10%, of the size of the largest sized non-clumping particles 46 configuring the litter 40 to be a low tracking litter have a tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch. This embodiment preferably also produces low-shedding litter clumps having a retention rate of at least 90%, preferably at least 95%, and more preferably at least 97%. The clumps can and preferably also do have a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.

[0080] In at least one of the aforementioned preferred embodiments, the low tracking litter 40 has clumping particles 42 composed of (1) extruded starch-based clumping pellets containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion- modified starch-based water soluble binder, and / or (2) substrate particles coated or plated with extruded starch-based clumping material 44 containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binder that absorb at least five and preferably at least six times the weight of the extruded starch- based clumping material of the pellet or particle in urine or water and which advantageously more rapidly swell when wetted with urine more quickly plugging voids between adjacent non-clumping particles 46 trapping urine at or near the top surface 52 of the litter 40 more speedily activating the water soluble binder of each wetted pellet’s or particle’s extruded starch based clumping material advantageously rapidly forming a litter clump on the top surface 52 of the litter 40. The use of clumping particles 42 composed of (1) extruded starch-based clumping pellets containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binder, and / or (2) substrate particles coated or plated with extruded starch-based clumping material 44 containing at least 5%, preferably at least 10%, more preferably at least 15% extrusion-modified starch-based water soluble binder advantageously forms shedding-resistant clumps that are harder, stronger and which do not crack, crumble, compress or otherwise shed when scooped out of the litter 40 with a litter scoop. Such shedding-resistant clumps preferably have a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% and a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch when clump retention tested and / or clump compression strength tested in accordance with the corresponding test procedures set forth in more detail herein.

[0081] At least one or more of aforementioned embodiments of the litter 40 can be and preferably are formulated to contain (a) at least 20%, preferably at least 25%, and more preferably at least about 30% of the clumping litter particles 42 by weight of the litter, and (b) no more than 45% and preferably no more than about 40% of the clumping particles 42. At least one or more of aforementioned embodiments of the litter 40 can be and preferably are formulated to contain (a) at least 20%, preferably at least 25%, and more preferably at least about 30% of the non-clumping litter particles 46 by weight of the litter, and (b) no more than 80%, preferably no more than 75%, and more preferably no more than about 70% of the non-clumping particles 46 by weight of the litter. In at least one preferred embodiment, the litter 40 is formulated to contain (a)(i) at least 20%, preferably at least 25%, and more preferably at least about 30% of the clumping litter particles 42, and (ii) no more than 45% and preferably no more than about 40% of the clumping particles 42, and (b)(i) at least 20%, preferably at least 25%, and more preferably at least about 30% of the non-clumping litter particles 46 by weight of the litter, and (ii) no more than 80%, preferably no more than 75%, and more preferably no more than about 70% of the nonclumping particles 46.

[0082] The larger-sized non-clumping litter particles 46 of at least one or more of the aforementioned above-disclosed embodiments of the litter 40 preferably have particle size of at least 3000 microns, preferably at least 3250 microns, and more preferably at least about 3350 microns and the smaller-sized clumping litter particles 42 have a particle size ofno greater than 2000 microns, preferably no greater than 1850 microns, and more preferably no greater than about 1700 microns. The larger-sized non-clumping litter particles 46 of at least one or more of the aforementioned embodiments of the litter 40 preferably have particle size of no greater than 5000 microns, preferably no greater than 4850 microns, and more preferably no greater than about 4750 microns and the smaller-sized clumping litter particles 42 have a particle size of at least 200 microns and preferably at least about 250 microns. In at least one embodiment, the smaller-sized clumping litter particles 42 have a particle size of at least 300 microns, preferably at least 400 microns, and preferably at least about 500 microns.

[0083] The non-clumping litter particles 46 of at least one or more of the aforementioned embodiments of the litter 40 disclosed hereinabove preferably have a non-clumping litter particle size distribution of between 3000 microns and about 5000 microns or have nonclumping particle sizes ranging from 3000 microns to 5000 microns. The clumping litter particles 42 of at least one or more of the aforementioned embodiments preferably have a clumping litter particle size distribution of between 200 microns and 2000 microns or have particle sizes ranging from 200 microns to 2000 microns. In at least one preferred litter formulation embodiment, (a) the clumping particles 42 have a particle size distribution of between 200 and 1800 microns and / or particle sizes ranging from 200 to 1800 microns, and (b) the non-clumping particles 46 have a particle size distribution of between 3250 and 4850 microns and / or particle sizes ranging from 3250 to 4850 microns.

[0084] The non-clumping litter particles 46 of at least one or more of the aforementioned embodiments of the litter 40 described above preferably have a non-clumping litter particle size distribution of between about 3350 microns and about 4750 microns or have nonclumping particle sizes ranging from about 3350 microns to about 4750 microns. The clumping litter particles 42 of at least one or more of the aforementioned embodiments preferably have a clumping litter particle size distribution of between about 250 microns and about 1700 microns or have particle sizes ranging from about 250 microns to about 1700 microns. In at least one preferred litter formulation embodiment, (a) the clumping particles 42 have a particle size distribution of between 250 and 1700 microns and / or particle sizesranging from 250 to 1700 microns, and (b) the non-clumping particles 46 have a particle size distribution of between 3350 and 4750 microns and / or particle sizes ranging from 3350 to 4750 microns.

[0085] In a further preferred embodiment of a low tracking litter 40 of the present invention, at least one of the formulations of the litter 40 is composed of (a) at least a plurality, preferably at least a plurality of pairs of, i.e., at least three, non-clumping particles having a non-clumping particle size range, and (b) at least a plurality, preferably at least a plurality of pairs of, i.e., at least three, clumping particles having a clumping particle size range, and where the ratio of the particle sizes of the non-clumping particles 46 relative to the sizes of the clumping particles 42 ranges from about 2:1 to about 14:1 thereby configuring the litter 40 to have a desirably low litter tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch. Such a litter 40 preferably also produces reduced-shedding clumps that have a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97% and which can have a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.

[0086] In one such preferred embodiment, the ratio of the smallest sized particles of the nonclumping particles 46 to the smallest sized particles of the clumping particles 42 ranges between about 7:1 and about 67:4 or about 16.75: 1, such as where the smallest size nonclumping particle 46 is about 3350 microns and the smallest size clumping particle 42 varies between 200 microns and 500 microns. In another such preferred embodiment, the ratio of the largest size particles of the non-clumping particles 46 to the largest sized particles of the clumping particles ranges between 19:6 and 19:8, such as where the largest size nonclumping particle 46 is about 4750 microns and the largest size clumping particle 42 varies between 1500 microns and 2000 microns.

[0087] Figure 2 illustrates another preferred but exemplary clumping cat litter 40’ that forms clumps when wetted with urine which is formulated with litter particles 42a, 42b, 46a, 46bof at least one non-clumping material having non-clumping litter particles 46a, 46b with particle sizes significantly larger than the particle sizes of litter particles 42a, 42b of at least one clumping material that configures the clumping litter 40’ to have such a low litter particle tracking effectiveness that it produces a low tracking clumping litter 42 in accordance with the present invention. The litter 40’ preferably has a litter tracking effectiveness of no greater than 100 particles per square inch, preferably no greater than 90 particles per square inch, and more preferably no greater than about 60 particles per square inch when tested in accordance with the litter particle tracking effectiveness test described in more detail below. Clumps formed using the litter 40’ possess reduced shedding during removal of a clump formed of litter particles 42a, 42b, 46a, 46b from litter 40’ in a litter box by having or being configured to have a clump retention rate of at least 90%, preferably at least 95%, and more preferably at least 97%. Clumps using litter 40’ preferably also have or are also configured to have a clump compression strength of at least 40 pounds per square inch, preferably at least 60 pounds per square inch, more preferably at least 100 pounds per square inch, and even more preferably at least 200 pounds per square inch.

[0088] In the preferred low tracking clumping litter embodiment depicted in Figure 2, the litter 40’ can have (a) a plurality of different non-clumping litter particles 46a, 46b, each preferably composed of a different type of non-clumping material, and each one of the nonclumping litter particles 46a, 46b can have particle sizes falling within one of a plurality of size ranges that can be and preferably are different from each other, and (b) a plurality of different clumping litter particles 42a, 42b, each preferably composed of a different type of clumping material, and each one of the different clumping litter particles 42a, 42b can have particle sizes falling within one of a plurality of size ranges that can be and preferably are different from each other.

[0089] The present invention also is directed to a clumping cat litter that minimizes tracking of the litter when a cat exits the litterbox and which preferably also minimizes the shedding of soiled litter from clumps upon removal, while ensuring that the resulting clumps that are formed are of high quality while the absorbency of the litter particles is maximized.

[0090] With reference once again to Figure 2, the clumping cat litter 40’ includes clumping litter particles 42a, 42b at least one clumping material and preferably a plurality of different clumping materials 44a, 44b, and includes non-clumping litter particles 46a, 46b of at least one non-clumping material and preferably a plurality of different types of non-clumping materials 48a, 48b. In one preferred embodiment, the litter 40’ includes a blend of a nonclumping calcium bentonite, a clumping sodium bentonite, and can include another clumping material that can be or contain an extruded starch-containing clumping material that preferably swells upon absorbing urine and activating an extrusion-modified starch- based water-soluble binder clumping agent. More preferably, the clumping cat litter includes a blend of non-clumping calcium bentonite forming non-clumping litter particles 46a of one type of clumping material 48a, clumping sodium bentonite forming clumping particles 42a of one type of clumping material 44a, and a swelling material that is an extruded product, such as preferably a high pressure extruded cereal grain, which preferably contains extrusion-modified water-soluble binder clumping agent in an amount of at least 5%, preferably at least 10%, more preferably at least 15% by weight, forming clumping litter particles 42b of another type of clumping material 44b. The high pressure extruded cereal grain clumping particles 42b, preferably in the form of extruded pellets, is water activated and swells as it absorbs water. While it at least partially solubilizes upon , the extruded clumping particles 42b swells upon rapidly absorbing urine wetting the particles 42b at least partially solubilizing extrusion-modified water-soluble binder clumping agent in each wetted particle 42b substantially simultaneously forming and / or releasing a pliable flowable adhesive glue that is conformable to any shape as it flows and gels adhering, attaching, and / or preferably even bonding to any other components, including adjacent litter particles 42a and / or 44, in the litter 40’ the flowable adhesive or glue contacts. Globules of this flowable clumping agent adhesive or glue can be and preferably are cleaved off by the urine stream which advantageously fill and preferably plug downstream voids in the litter 40’ as its viscosity rapidly thickens into a gel which in turn solidifies trapping urine above it at or near the top surface 52 of the litter. The advantageously causes a clump of the litter particles 42a, 42b and / or 46a to form on top 52 of the litter 40’

[0091] The present cat litter formulation differs significantly in terms of the particle size ranges and percentages by weight of the respective components in comparison to prior art litter formulations. More specifically, the non-clumping particles 46a and / or 46b have larger particle sizes and size ranges with larger particle sizes at each range boundary than the particle sizes and particle size ranges of prior art clumping litters. Ranges of particle sizes of the present litter 40 or 40’, the sizes of the clumping particles 42, 42a, and / or 42b and non-clumping particles 46, 46a, and / or 46b may vaiy so long as the clumping particles 42, 42a, and / or 42b are small enough relative to the sizes of the significantly larger nonclumping particles 46, 46a and / or 46b so that the smaller clumping particles 42, 42a and / or 42b are substantially completely disposed below the surface 52 of the litter 40 or 42’ away from contact with a cat’s paw treading on the litter’s surface 52 during use of the litter 40 or 40’. Ranges of particle sizes of the present litter 40 or 40’, the sizes of the clumping particles 42, 42a, and / or 42b and non-clumping particles 46, 46a, and / or 46b may vary so long as the clumping particles 42, 42a, and / or 42b are small enough relative to the sizes of the non-clumping particles 46, 46a and / or 46b so that the smaller clumping particles 42, 42a and / or 42b form a matrix when wetted with urine that produces a clump that is strong, possesses good clump integrity, possess a high clump retention rate greater than 90%, preferably greater than 95% and more preferably greater than 97%. This configuration results in the smaller clumping particles 42, 42a and / or 42b being small enough to be contained within the voids of the much larger non-clumping particles 46, 46a and / or 46b, with the non-clumping particles 46, 46a and / or 46b being sufficiently large relative to the size of the much smaller clumping particles 42, 42a and / or 42b to allow clumping materials, including clumping agent(s) thereof, of urine wetted clumping particles 42, 42a and / or 42b to fill channels created by voids between adjacent non-clumping particles 46, 46a and / or 46b. This prevents the non-clumping particles from interrupting the clumping particles from forming an interlocking matrix produced by the release of clumping agent, preferably including extrusion-modified starch-based water-soluble binder, in the clumping material of the clumping particles 42, 42a and 42b, preferably extruded clumping particles 42b, that encapsulates both the clumping and non-clumping particles 42 and / or 46 or 42a, 42b, 46aand / or 46b into a wet / damp ball like clump. In order to facilitate this result, preferably no more than 10% by weight of the particles 42, 42a, and / or 42b, 46, 46a and / or 46b of the clumping and non-clumping materials 44 and 48 and / or 44a, 44b, 48a and / or 48b overlap in particle size. Most preferably, no more than 5% of the particles 42, 42a, 42b, 46, 46a and / or 46b of the clumping and non-clumping materials 44 and 48 and / or 44a, 44b, 48a and / or 48b overlap in particle size.

[0092] In one embodiment of the present invention, the particle sizes of all of the nonclumping particles are larger than the particle sizes of the clumping particles. As a result of this configuration, clumping occurs where the smaller clumping particles fill the large voids between and around the non-clumping particles. Because of the differences in particle size distribution of the non-clumping particles relative to the clumping particles, the clumping particles are small enough to fit into the voids formed between and around adjacent nonclumping particles. When urine enters litterbox 50, this causes the clumping agent(s) of the clumping particles to instantly swell and block the urine from traversing through the litter 40 or 40’ downwardly to the bottom of the litterbox 50. This clumping agent from the urine wetted clumping particles flows into the urine stream and plugs holes and voids in between and around non-clumping particles, blocking the urine stream from flowing downwardly trapping the urine at or near the surface 52 of the litter 40 or 40’ resulting in the formation of clumps on top of the litter 40 or 40’.

[0093] Turning to Table 1 of Figure 5, the percentages by weight of the various clumping materials 44a and / or 44b of the clumping particles 42a and / or 42b, and non-clumping materials 48a and / or 48b of the non-clumping particles 46a and / or 46b contained in six formulations of low tracking litter product trials formulated in accordance with present invention are presented, with each containing approximately 70% by weight in nonclumping particles 46 of a non-clumping material 48, such as calcium bentonite 48, or a blend of non-clumping particles 46a of calcium bentonite 48a and non-clumping particles 46b of walnut shells 48b, and approximately 30% by weight in clumping particles 42 of a clumping material 44 such as sodium bentonite 44 or a blend of clumping particles 42a of sodium bentonite 44a and clumping particles 42b of an extruded water-absorbent pellets 42bof extruded starch-based material composed of extrusion-modified starch-based water soluble binder clumping agent 44b in an amount of at least 5%, preferably 10%, more preferably 15% by pellet weight, e.g., lightweight natural grass / extruded cereal grain 44b. In certain preferred embodiments of the present invention, the non-clumping pellets 46a and / or 46b and / or their non-clumping material 48a and / or 48b makes up approximately 60- 70% by weight of the low tracking litter mixture, blend or formulation. In one preferred embodiment of the present invention, non-clumping particles 46 or 46a of calcium bentonite 48 or 48a makes up approximately 70-80% by weight of the low tracking litter mixture, blend or formulation, while in others the non-clumping particles 46a, 46b is respectively made up of approximately 30-40% by weight of calcium bentonite 48a and approximately 30-40% by weight of walnut shells 48b. In certain embodiments, the clumping particles 42a, 42b are made up of approximately 10-15% by weight of sodium bentonite 44a and approximately 10-15% by weight of extruded cereal grain, while in other embodiments the clumping material is approximately 5-15% by weight of sodium bentonite and approximately 15-25% by weight of extruded cereal grain 44b that preferably is extruded starch-based material composed of extrusion-modified starch-based water soluble binder clumping agent in an amount of at least 5%, preferably 10%, more preferably 15% by pellet weight. In yet other embodiments, the clumping particles can also include or be composed of a guar gum plated onto substrate particles, e.g., non-clumping and / or non-absorbent particles, such as in the manner discussed above, having a particle size or particle sizes smaller than the non-clumping particles 46a and / or 46b used in the litter 40 or 40’. The specific particle size distributions of each of these clumping particles and clumping material and these non-clumping particles and non-clumping particles of the low tracking litter product trial nos. 1 through 6 are contained in Table 2 of Figure 6. Because of the particle size distributions of the clumping particles and non-clumping particles of the respective formulation trial numbers 1 through 6 of the present invention, a low tracking litter 40 or 40’ of the present invention is formulated to be configured to have approximately 70% or more of the surface area of the top surface 52 of the litter 40 or 40’ in a litter box 50 exposed to paws of a cat using the litter being composed of non-clumping particles 46aand / or 46b having particle sizes greater than 1700 microns that is too large to become adhered to the cat’s paw and be tracked from the litter 40 or 40’ outside of the litterbox 50.

[0094] While serving as an effective clumping litter, the present litter formulations have the additional benefit of being lightweight in comparison to prior art clumping litters. For instance, the clumping particles 42b composed of high pressure extruded cereal grain that preferable is or includes extruded starch-based material composed of extrusion-modified starch-based water soluble binder clumping agent 44b in an amount of at least 5%, preferably 10%, more preferably 15% by pellet weight has approximately 1 / 5 of the bulk density of sodium bentonite 44a used for clumping particles 42a, and 1 / 3 of the bulk density of the non-clumping materials 48, 48a and / or 48b used for the non-clumping particles 46, 46a, and / or 46b. Thus, by increasing the proportion clumping particles 42 or 42a made of high pressure extruded cereal grain, extruded starch-based material composed of extrusion- modified starch-based water soluble binder clumping agent 44b in an amount of at least 5%, preferably 10%, more preferably 15% by pellet weight, and non-clumping particles 46 or 46a calcium bentonite 48 or 48a, the weight of the litter 40 or 40’ decreases in comparison to traditional clumping cat litters having a larger proportion of litter particles of sodium bentonite.

[0095] Despite the lightweight nature of the low tracking litter trial formulation number 1-7, each formula results in quality clumps as reflected by the drop test results for each one of the trial formulation numbers contained in Table 3 of Figure 7. As shown, two clumps were formed and weighed for each litter formulation trial number of the present invention. Thereafter, clump drop tests were conducted at intervals of ten minutes and thirty minutes, after which the clumps were again weighed and compared to the pre-drop rate. Clump retention percentages were then calculated. These results are comparable to those for existing commercially available clumping litters, which weigh considerably more than low tracking formulation numbers 1-7 made in accordance with present invention.

[0096] Furthermore, as shown in Table 4 of Figure 8, each one of the six low tracking litter formulation trial numbers possess superior tracking characteristics as embodied by their respective litter particle tracking effectiveness numbers in Table 4 which were significantlylower, typically half, compared to several commercially available prior art clumping litters also listed in Table 4. This is because the sizes and types of clumping and non-clumping particles and materials used to make the blends of formulation trial numbers 1-6 were selected to maximize the amount of voids that are filled around the larger calcium bentonite particles 46a. Such a low tracking litter formulation where the voids around the calcium bentonite particles 46a are filled results in less movement of all of the litter particles 42a, 42b, 46a and / or 46b. Stated differently, such low tracking formulations do so by minimizing the amount of deflection of particles 42b, 46a and / or 46b when a cat steps onto the surface 52 of litter 40 or 40’ in the litterbox 50, which in turn minimizes the amount of tracking of the particles 42a, 42b, 46a and / or 46b from the box 50.

[0097] The amount of moisture on a cat’s paws can also influence the amount of tracking. A wet paw is more likely to track clumping particles 42a and / or 42b composed of clumping material 44a and / or 44b out of the litterbox 50. Thus, by increasing the percentage by weight of the non-clumping materials 46a and / or 46b, for example, calcium bentonite 46a and / or walnut shells 46b, the amount of tracking of litter particles 42a, 42b, 46a and / or 46b from the litter box 50 can further be reduced. Furthermore, static charges, which are common because cat fur oftentimes generates charges, can also impact the amount of tracking. Calcium bentonite 48a as well as walnut shells 48b advantageously do not carry charges, such that particles 46a and / or 46b these non-clumping materials 48a and / or 48b do not commonly attach to the cat’s fur based on charges in the fur. As shown in the data in Table 4 of Figure 8, all six low hacking litter trial formulation made in accordance with the present invention have a lower number of particles present on the pad compared to the commercially available prior art litter blends - they typically hack less than half as many litter particles as these commercially available prior art litter blends do.

[0098] It is also to be understood that, although the foregoing description and drawings describe and illustrate in detail one or more preferred embodiments of the present invention, to those skilled in the art to which the present invention relates, the present disclosure will also suggest various modifications, constructions, and alternatives, as well as different embodiments and applications all of which are contemplated as being within the scope ofthe invention. The present invention, therefore, is intended to be limited only by the scope of the appended claims.

Claims

CLAIMSIt is claimed:

1. A low tracking clumping litter comprised of a blend of clumping litter particles comprised of a clumping material and of non-clumping litter particles.

2. The low hacking clumping litter of claim 1, wherein the non-clumping particles have a particle size that is larger than a particle size of the clumping particles.

3. The low hacking clumping litter of claim 2, wherein the low hacking litter has a liber particle hacking effectiveness of no more than 100 particles per square inch.

4. The low hacking clumping liber of claim 3, wherein the low hacking liber has a liber particle hacking effectiveness of no more than about 90 particles per square inch.

5. The low hacking clumping liber of claim 3, wherein the low hacking liber has a liber particle tracking liber effectiveness of no more than about 100 particles per square inch adhered to an outer liber particle pickup surface of a low hacking liber particle pickup pad contacting the low hacking liber.

6. The low hacking clumping liber of claim 5, wherein the low hacking liber particle pickup pad is comprised of a fibrous pad abached to a backing layer and a handle at least carrying the fibrous pad, wherein the outer liber particle pickup surface of the fibrous pad is pressed into a top surface of the low tracking liber received in a liber box and removed, and wherein the number of particles of the non-clumping liber and clumping liber retained on the fibrous outer surface of the pad are counted.

7. The low backing clumping liber of claim 6, wherein the number of particles of the non-clumping liber and clumping liber retained on the fibrous outer surface of the pad areremoved therefrom and counted to obtain the liber particle hacking effectiveness of the low hacking liber.

8. The low hacking clumping litter of claim 2, wherein the non-clumping particles have a non-clumping particle size range comprised of non-clumping particles having a plurality of particle sizes, and the clumping particles have a clumping particle size range comprised of clumping particles having a plurality of particle sizes that are smaller than the particle sizes of the non-clumping particles of the non-clumping particle size range.

9. The low hacking clumping litter of claim 2, wherein the non-clumping particles have a non-clumping particle size range comprised of non-clumping particles having a plurality of particle sizes, and the clumping particles have a clumping particle size range comprised of clumping particles having a plurality of particle sizes that are smaller than the particle sizes of the non-clumping particles of the non-clumping particle size range configuring the clumping litter to have a top surface comprised of the larger non-clumping particles with the smaller clumping particles disposed below the top surface of the clumping litter.

10. The low hacking clumping liber of claim 9, wherein the clumping liber is further configured with a packing arrangement comprised of (a) a plurality of pairs of layers of the non-clumping liber particles defining a plurality of pairs of voids between adjacent nonclumping liber particles of the adjacent layers of the non-clumping liber particles, and (b) a plurality of pairs of the clumping particles disposed in the voids between adjacent nonclumping particles of each one of the adjacent layers of the non-clumping particles.

11. The low h acking clumping liber of claim 10, wherein a ratio of the lower nonclumping particle size range boundary to the lower clumping particle size boundary is no less than about 2: 1 and a ratio of the upper non-clumping particle size range boundary to the upper clumping particle size range boundary is no greater than about 14:1.

12. The low tracking clumping litter of claim 10, wherein a ratio of the particle sizes of the non-clumping particles to the particle sizes of the clumping particles ranges between 2: 1 and 14: 1.

13. The low tracking clumping litter of claim 1, wherein the clumping particles are comprised of extruded starch-based water-soluble binder containing clumping material and the non-clumping particles are comprised of one of calcium bentonite and comminuted walnut shells.

14. The low tracking clumping litter of claim 1, wherein the clumping particles are comprised of one of an extruded starch-based water-soluble binder containing clumping material and sodium bentonite, and the non-clumping particles are comprised of one of calcium bentonite and comminuted walnut shells.

15. The low tracking clumping litter of claim 1, wherein there are clumping particles comprised of an extruded starch-based water-soluble binder containing clumping material and clumping particles comprised of sodium bentonite, and there are non-clumping particles are comprised of calcium bentonite.

16. The low tracking clumping litter of claim 15, further non-clumping particles comprised of comminuted walnut shells.

17. The low tracking clumping litter of claim 1, wherein: at least a plurality of non-clumping particles have particle sizes falling within a nonclumping particle size range defined by a lower range boundary non-clumping particle size and an upper range boundary non-clumping particle size, and at least a plurality of clumping particles have particle sizes falling within a clumping particle size range defined by a lower range boundary clumping particle size and an upper range boundary clumping particle size; a non-clumping particle size to clumping particle size ratio ranging from about 2: 1 for non-clumping particles and clumping particles having a particle size at the respectivelower range boundary of the corresponding non-clumping and clumping particle size ranges to about 14: 1 for non-clumping particles and clumping particles having a particle size at the respective upper range boundary of the corresponding non-clumping and clumping particle size ranges; and a low tracking litter effectiveness of no more than 100 particles per square inch adhered to a low tracking litter pickup pad contacting the low tracking litter.

18. The low tracking clumping litter of claim 17, wherein the low tracking litter has a litter particle tracking effectiveness of no more than about 90 particles per square inch.

19. The low hacking clumping litter of claim 17, wherein the clumping particles are comprised of extruded starch-based water-soluble binder containing clumping material and the non-clumping particles are comprised of one of calcium bentonite and comminuted walnut shells.

20. The low hacking clumping litter of claim 17, wherein there are clumping particles comprised of extruded starch-based water-soluble binder containing clumping material and clumping particles comprised of sodium bentonite, and there are non-clumping particles are comprised of one of calcium bentonite and comminuted walnut shells.

21. The low hacking clumping litter of claim 20, wherein there are non-clumping particles are comprised of calcium bentonite and non-clumping particles comprised of comminuted walnut shells.

22. A low hacking clumping litter comprised of: approximately 70% by weight of a non-clumping clay material; and approximately 30% by weight of a clumping material; wherein the litter forms a removable clump when urine is applied thereto.

23. The lightweight clumping granular litter of claim 33, wherein the clumping material comprises one or more of a sodium bentonite clay and a cellulosic material.

24. The lightweight clumping granular litter of claim 23, wherein the cellulosic material is a high pressure extruded cereal grain.

25. The lightweight clumping granular litter of claim 24, wherein the non-clumping clay material is a calcium bentonite clay.

26. The lightweight clumping granular litter of claim 25, wherein the high pressure extruded cereal grain has a lower bulk density than the sodium bentonite clay and the calcium bentonite clay.

27. The lightweight clumping granular litter of claim 25, wherein the sodium bentonite clay particles and the high pressure extruded cereal grains swell and stick to the calcium bentonite particles when urine is applied thereto.

28. The lightweight clumping granular litter of claim 25, wherein the mean particle size of the calcium bentonite clay is larger than the mean particle size of the sodium bentonite clay and the high pressure extruded cereal grain.

29. The lightweight clumping granular litter of claim 28, wherein the particle size distribution of the litter minimizes tracking of the non-clumping clay material and clumping material outside of a litterbox.

30. The lightweight clumping granular litter of claim 22, wherein the clumping material particles are between approximately 250 microns and approximately 1680 microns.

31. The lightweight clumping granular litter of claim 22, wherein the clumping material particles are between approximately 250 microns and approximately 500 microns.

32. The lightweight clumping granular litter of claim 22, wherein the non-clumping material particles are between approximately 1680 microns and approximately 4760 microns.

33. The lightweight clumping granular litter of claim 1, wherein the clumping particles have particles sizes of between approximately 250 microns and approximately 1680 microns.

34. The lightweight clumping granular litter of claim 1, wherein the clumping particles have particles sizes of between approximately 500 microns and approximately 1680 microns.

35. The lightweight clumping granular litter of claim 1, wherein the non-clumping particles have particles sizes ranging between approximately 1680 microns and approximately 4760 microns.

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