Compressible granular animal litter

Abstract

An animal litter product comprising a foamed polymer wherein the foamed polymer is compressible, resilient and has a density in the range of about 81 to 650 kg / m3 wherein the foamed polymer has a limited compressibility and restores to 70% of its original volume wherein, optionally, the foamed polymer is mixed with other animal litter components, such as clay or other absorbent materials.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Utility Patent Application No. 17 / 981,173, filed on November 4, 2022, which is incorporated herein by reference. Technical field

[0003] The present invention relates to animal litter, and more particularly, to a compressible animal litter. Containers with smaller volumes have lower transportation costs and are also easier to shelve. The compressible litter contains a compressible elastic foam polymer with a suitable density. Background art

[0004] Animal litters, pet litters, and cat litters in the prior art are well - known in the art. Desirable characteristics of an ideal animal litter are water absorbency, clumping ability, and odor control.

[0005] None of the following references disclose a compressible animal litter for transportation. The transportation cost of pet litter can account for a large part of the final product. If the product volume can be reduced, the transportation cost can also be reduced. The product also needs to be elastic, that is, after the compressive force is released, the foam is elastic and can return to near its original volume. A suitable density also helps animals (such as cats) use the litter.

[0006] US3,765,371 discloses the use of plastic foam particles in cat litter. This patent discloses that the plastic foam can be reused as cat litter after being washed. The plastic material disclosed in this patent has a high surface area and can effectively absorb urine or feces. The plastic foam has a low weight per unit of absorbed volume, so by minimizing the transportation weight, the transportation and distribution costs can be minimized. This patent neither mentions elastic, compressible foam nor the necessity of minimizing the transportation volume. Although the listed plastic foams, namely (rigid) polyvinyl chloride foam, (rigid) polystyrene foam (also known as ), (rigid) porous cellulose acetate resin, (rigid) phenolic foam resin, and polyurethane foam, are disclosed, compressible foam or elastic foam is not mentioned. Among the listed foams, only polyurethane foam is both called elastic foam and rigid foam. For this patent, polyurethane foam belongs to rigid foam because the other four listed foams are all rigid foams and the reduction of transportation volume is not mentioned. Such rigid foams are neither compressible nor elastic.

[0007] US 3,765,371 does not disclose the density of the foam. The patent does state that the foam is lightweight, thus saving on shipping costs, but does not specifically state what density would be considered lightweight. The present invention relates to a compressible and resilient animal litter, and density is an important consideration because foam with too low a density does not provide an ideal cat litter, as when a cat walks through the litter, its claws will sink into the bottom of the litter box, causing discomfort. Cats prefer to walk on a surface that can support their claws and does not sink. Additionally, when a cat scratches to cover its feces, low-density foam will scatter outside the litter box or stick to its claws instead of covering the excrement. Alternatively, foam with too high a density is not compressible enough.

[0008] WO 2008007963 discloses a cat litter containing protein-based rigid foam and other rigid foams.

[0009] None of the above documents disclose or suggest the use of a compressible and resilient foam polymer in animal litter. Summary of the Invention

[0010] An animal litter product comprising a foam polymer, wherein the foam polymer block is a compressible and resilient foam having a density in the range of about 81 to 650 kg / m 3 The claimed animal litter is not easily compressible, so when an animal (e.g., a cat) uses it, the animal's claws will sink too deeply into the litter. A limited compression rate is required, otherwise the animal will not use the litter because it will feel uncomfortable when walking on it and sinking in. The preferred resilient foam polymer has a volume compression rate of less than about 10% or more when tested as a complete block at a pressure of about 1 kg / 4 cm 2 Preferably, the compression rate is about 4 volume % to 10 volume %. The granular litter can be tested by applying a force of 0.936 kg over an area of 7.94 cm 2 and has a volume compression rate of about 4% to 30%. Preferably, the volume compression rate of the granular litter is about 5% to 25%.

[0011] In a preferred embodiment, the foam polymer is mixed with other animal litter components (such as clay or other absorbent materials). To prevent particle separation (i.e., separation of the particles after mixing or storage), the ratio of the density of the foam to the density of the other animal litter must be in the range of about 1:10 to about 1:1.

[0012] More application areas of the present invention will be apparent from the following detailed description. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are for illustrative purposes only and are not intended to limit the scope of the invention. Detailed Description

[0013] The following description of the preferred embodiments is merely exemplary and is not intended to limit the invention, its application, or uses in any way.

[0014] The density of the preferred compressible, resilient foam is in the range of about 81 to 650 kg / m 3 The upper limit of the foam density is related to its compression rate. Foams with very high densities (greater than 650 kg / m 3 ) will lose their compression ability under the required conditions. Densities below about 81 kg / m 3 will result in over-compression of the foam, and the animal's claws will sink too deeply into the foam, making the animal reluctant to walk on it. In a preferred embodiment, the foam density is about 325 to 550 kg / m 3 .

[0015] The preferred foam, as a complete block, has a volume compression rate of about 30% or less when compressed under a pressure of about 1 kg / 4 cm 2 . This can be used to measure the hardness by indentation force deflection. This embodiment is determined by measuring the point compression rate of an ordinary domestic cat, which weighs about 4 to 5 kg. The compression of a four-pawed animal is about 1.0 kg. The approximate area of the footprint is 4 cm 2 . Since it is desired that the cat's claws do not sink too deeply into the litter and do not spill out of the litter box, for a complete foam block, a compression rate of about 30% or less under a pressure of 1.0 kg / 4 cm 2 is ideal. In a preferred embodiment, the volume compression rate is about 5% to 25%. Most preferably, the compression rate is less than 20%.

[0016] A second method of measuring the indentation force deflection of granular cat litter is to apply a pressure of 0.936 kg to an area of 7.94 cm 2 of the litter. The litter is placed in a container that is at least 5.8 cm deep, which is the typical depth of cat litter in a litter box. The compression rate is equal to the height of the litter after the weight is applied divided by the height of the litter before the weight is applied. Preferably, the compression rate under these test conditions is less than 50%. More preferably, the compression rate is less than 30%. Most preferably, the compression rate is about 5% to 25%. The rebound rate of the granular foam is also measured using this test. After 4 hours, the height of the litter is measured to determine the rebound rate, which is the percentage of the height that returns to the original unweighted height. Preferably, the rebound rate is at least 70% of the original height. More preferably, the rebound rate is at least 90% of the original height. Most preferably, the rebound rate is about 100% of the original height.

[0017] In a preferred embodiment, the foam is in the shape of a three-dimensional polygon. Preferably, the polygon is approximately rectangular. This shape allows the cat litter to be roughly aligned when spread in the litter box and reduces over-compression. Compared with fragmented (irregularly shaped) foam, the polygonal foam under 1.0 kg / 4 cm 2is compressed less under pressure. Preferably, the size of the polygon is less than 1.27 cm. More preferably, its size is less than about 0.952 cm. Most preferably, the size of the rectangular polygon is about 0.318 cm × 0.318 cm × 0.636 cm. Circular or spherical shapes are not ideal because when a cat steps on the cat litter, it can cause the cat litter to move and scatter. In one embodiment, the foam is not absorbent.

[0018] Closed-cell polyurethane foam is the preferred elastomeric compressible foam. Open-cell polyurethane foam is too compressible. Examples of preferred polyurethane foams include: Poron 4701-40-20125soft001 (unsupported, density of 333 kg / m 3 ) and Comcast Urethane (density of 519 kg / m 3 ).

[0019] In another embodiment, the preferred elastomeric foam is polyethylene foam. The preferred foam is extruded into the desired shape. The preferred foam is a closed-cell foam. In a preferred embodiment, the polyethylene foam is made using isobutane as a blowing agent. Extruded foam has an advantage over shredded foam because it has better structural properties and higher uniformity.

[0020] The elastomeric compressible foam used in this animal litter does not include rigid foams such as rigid polyvinyl chloride, rigid polystyrene foam, rigid honeycomb cellulose acetate resin, rigid phenolic foam resin, and rigid polyurethane foam. Additionally, the elastomeric compressible foam does not include sponge cellulose (98% cellulose) with a density of about 35 kg / m 3 .

[0021] In a preferred embodiment, the animal litter made of the claimed elastomeric compressible foam is completely dust-free.

[0022] In a preferred embodiment, the compressible foam animal litter is wrapped in a flexible sealed container, which is compressed to expel excess air and then the container is vacuum-sealed. When using the animal litter, open the container to let air in and then place the litter in a desired container such as a cat litter box for standby.

[0023] In one embodiment, the foam is made by cutting or shredding a large block of foam into the desired size. Alternatively, the foam block can be formed by extrusion or molding. In a more preferred embodiment, the foam particles are formed by spray-drying a polyol / isocyanate mixture (for manufacturing polyurethane foam) to form substantially spherical polyurethane foam particles. In a preferred embodiment, the foam is extruded foam.

[0024] In a preferred embodiment, the foam of the present invention is used in combination with other well-known non-foam animal litter components (e.g., liquid-absorbing clay materials), and the use of these components does not depart from the spirit and scope of the present invention. The weight ratio of the foam to the non-foam animal litter components is about 10:1 to 1:10.

[0025] To prevent particle separation (i.e., separation of particles after mixing or storage), the density ratio of the foam to the density of other cat litter components must be in the range of about 1:10 to about 1:1.

[0026] Suitable absorbent clays include, but are not limited to, bentonites such as sodium-based bentonite, attapulgite, montmorillonite, diatomaceous earth, Georgia white clay, sepiolite, slate, pumice, tobermite, marl, kaolinite, halloysite, green clay, lithium montmorillonite, fuller's earth, zeolite, and mixtures thereof. The density of the clay is typically in the range of about 800 to 2000 kg / m 3 range. In addition to the clay, fillers such as limestone, sand, calcite, dolomite, recycled waste, zeolite, and gypsum can be used in combination with the clay.

[0027] The present invention also contemplates other absorbent materials including, but not limited to, rice, nut shells, recycled corrugated cardboard, by-products and pulp, barley, wheat, corn, tofu, wood, paper, and other plant-based materials, as well as silica gel.

[0028] Other materials include, but are not limited to, antibacterial agents, odor absorbents / inhibitors, binders, fragrances, health indicator materials, non-stick release agents, superabsorbent materials, and mixtures thereof. Antibacterial active substances include boron-containing compounds such as borax pentahydrate, borax decahydrate, boric acid, polyborates, tetraboric acid, anhydrous sodium metaborate, boron components in polymers, and mixtures thereof.

[0029] Absorbing / inhibiting odor active ingredients include water-soluble metal salts such as silver salts, copper salts, zinc salts, iron salts, and aluminum salts, and mixtures thereof. Zinc chloride, zinc gluconate, zinc lactate, zinc maleate, zinc salicylate, zinc sulfate, zinc ricinoleate, copper chloride, copper gluconate, and mixtures thereof are effective. Other odor control active ingredients include metal oxide nanoparticles. Other types of absorbing / inhibiting odor active ingredients include cyclodextrin, zeolite, activated carbon, acid-forming salts, and mixtures thereof. The active ingredient can be calcium-based bentonite added to reduce adhesion to the litter box.

[0030] The active ingredient may also include binders such as water, lignosulfonate (solid), polymer binders, (Polytetrafluoroethylene or PTFE), and combinations thereof. Useful organic polymerizable binders include, but are not limited to, hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC), carboxymethyl cellulose (CMC) and its derivatives and metal salts thereof, guar gum cellulose, xanthan gum, starch, lignin, polyvinyl alcohol, polyacrylic acid, styrene butadiene resin (SBR), and polystyrene acrylic resin. The water-stable particles can also be made of a crosslinked polyester network, including but not limited to a crosslinked polyester network formed by the reaction of polyacrylic acid or citric acid with different polyols (such as glycerol, polyvinyl alcohol, lignin, and hydroxyethyl cellulose).

[0031] To reduce the dust content, a dust remover can also be added to the particles. Many of the binders listed above are effective dust removers when applied to the outer surface of the composite absorbent particles. Other dust removers include, but are not limited to, gums, resins, water, and other liquids or liquefiable materials.

[0032] Examples of the present invention

[0033] Density, compression ratio, and rebound ratio tests were performed on sponge cellulose (Control 1), Poron 4701-40-20125soft001, unsupported foam (Example 1), and Comcast polyurethane (Example 2) foam samples as follows:

[0034] Density test - Each foam polymer sample was measured and weighed. The density was calculated as the mass / volume ratio and recorded in kg / m 3 units. See Table 1.

[0035] Compression ratio test - A complete 2 cm × 2 cm × 1.2 cm foam polymer sample was taken, and the height was measured with calipers. The compression ratios of the samples of Control 1, Example 1, and Example 2 were tested. A weight of about 1.0 kg was placed on the sample, and the height was measured again. The height difference was calculated, and the percentage of volume loss was determined. See Table 1.

[0036] The rebound ratio was determined by measuring the height again 24 hours after removing the weight in the compression ratio test. The results are shown in Table 1.

[0037] Table 1 - Foam samples

[0038]

[0039] The density of Control 1 is much lower than the claimed density of animal sand, and there is no compression ratio and rebound ratio. The densities, compression ratios, and rebound ratios of Examples 1 and 2 meet the requirements.

[0040] When used as granular cat litter by cats, Example 2 was found to work well in the cat litter box.

[0041] The test methods for Example 3 and Example 4 were to apply a weight of 0.936 kg to granular sand with an area of 7.94 cm 2 The sand was placed in a container with a depth of at least 5.8 cm. The compression ratio was calculated by dividing the height of the sand after the applied force by the height of the sand before the applied force. The results are shown in Table 2.

[0042] Table 2 - Foam Samples

[0043]

[0044] Example 3 and Example 4 were tested for use by cats in a litter box. Both samples were effective for cats, but cats preferred Example 4 because it had a lower compression ratio and smaller particle size.

[0045] These examples were selected and described to best explain to those skilled in the art the principles of the present invention and its practical applications. Since various modifications can be made to the exemplary embodiments described with reference to the corresponding descriptions above without departing from the scope of the present invention, all of the content included in the foregoing description and shown in the accompanying drawings should be construed as illustrative rather than restrictive. Therefore, the breadth and scope of the present invention should not be limited by any of the above exemplary embodiments, but should be defined only in accordance with the appended claims and their equivalents.

Claims

1. An animal litter, comprising a foam polymer, wherein the foam polymer is granular; wherein the foam polymer is a compressible and elastic foam having a density in the range of 81 to 650 kg / m 3 ; wherein when a weight of 1.0 kg is applied, the compression rate of the foam polymer is less than 30%; wherein when the weight is removed, the foam polymer returns to at least 70% of its original volume; and wherein the foam is formed into non-spherical particles having a size of 1.27 cm or less.

2. The animal litter according to claim 1, wherein a weight of 0.936 kg is applied to the granular cat litter having an area of 7.94 cm 2 ; and wherein the compression rate is 5% to 25%.

3. The animal litter according to claim 2, wherein the volume of the foam polymer is compressed by less than 20%.

4. The animal litter according to claim 3, wherein the animal litter is a mixture of foam polymers.

5. The animal litter according to claim 4, wherein the foam polymer is a closed-cell polyurethane foam.

6. The animal litter according to claim 5, wherein the foam polymer is cut, shredded, extruded, molded or spray-dried into particles smaller than 1.27 cm.

7. The animal litter according to claim 6, wherein the foam polymer is an extruded polyethylene foam.

8. The animal litter according to claim 7, wherein the shape of the foam polymer particles is a rectangular polygon having a size of 0.925 cm or less.

9. An animal litter, comprising granular foam polymer and a non-foam component, wherein the foam polymer is a compressible and elastic foam having a density in the range of 81 to 650 kg / m 3 ; wherein when a weight of 1.0 kg is applied, the foam polymer has a limited compression rate; wherein when the weight is removed, the foam polymer returns to about 70% of its original volume; wherein the foam is formed into particles of 1.27 cm or less; and wherein the weight ratio of the foam polymer to the non-foam component is in the range of 10:1 to 1:

10.

10. The animal litter according to claim 9, wherein the non-foam component includes a liquid-absorbing clay; and wherein the density of the non-foam component of the non-foam composition is in the range of 800 to 2000 kg / m 3 range.

11. The animal litter according to claim 10, wherein when a weight of 0.936 kg is applied to the granular litter having an area of 7.94 cm 2 area; wherein the animal litter is placed in a container having a depth of at least 5.8 cm; and wherein the volume of the foam polymer is compressed by less than 20%.

12. The animal litter according to claim 10, wherein the volume of the foam polymer is compressed by 5% to 25%.

13. The animal litter according to claim 12, wherein the foam polymer does not contain rigid foams selected from the group consisting of rigid polyvinyl chloride, rigid polystyrene foam, rigid honeycomb cellulose acetate resin, rigid phenolic foam resin, and rigid polyurethane foam.

14. The animal litter according to claim 13, wherein the foam polymer is selected from the group consisting of closed-cell polyurethane foam and extruded closed-cell polyethylene foam.

15. The animal litter according to claim 14, wherein the foam polymer is cut, shredded, extruded, molded, or spray-dried into particles smaller than 1.27 cm, and wherein the particles are non-spherical.

16. The animal litter according to claim 15, wherein the polyethylene foam uses isobutane as a blowing agent to form foam during extrusion.

17. The animal litter according to claim 16, wherein the foam polymer is cut into rectangular polygons having a size of 0.925 cm or less.

18. An animal litter comprising a foam polymer, wherein the foam polymer is granular; wherein the foam polymer is a compressible and elastic foam having a density in the range of 325 to 550 kg / m 3 range; wherein when a weight is applied, the foam polymer has a limited compression rate; wherein when the weight is removed, the foam polymer returns to about 90% of its original volume; wherein the weight is 0.936 kg; wherein the weight is applied to the granular litter having an area of 7.94 cm 2 area; wherein the compression rate is less than 30%; and wherein the foam polymer is cut, shredded, extruded, molded, or spray-dried into non-spherical particles smaller than 1.27 cm.

19. The animal litter according to claim 18, wherein the volume of the foam polymer is compressed by 5% to 25%, and wherein the shape of the foam polymer particles is polygonal.

20. The animal litter according to claim 19, wherein the shape of the foam polymer particles is a rectangular polygon with dimensions of 0.2 cm to 0.952 cm.

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