1. Field of the Invention
The present invention relates to additives for animal litter; and more particularly to an additive for cat litter, which releases an odor controlling or odor masking substance when the animal uses a litter-box.
2. Description of the Prior Art
Many patents disclose methods for control of odor in animal litter. When animal litter is not of a clumping variety, it is difficult to control the odor since the urine excreted is absorbed over a much larger distance. Clumps are created when the composition of the swells during the absorption of pet urine, creating a localized rigid clump. Typical additives for litter which provide this swelling and urine absorption property include gypsum, calcium sulfate hemi-hydrate which absorbs water, forming CaSO4.2H20, swelling Kaolin or montmorillonite clays. Gums of different variety are also used to dissolve and form a bond, creating clumps. Odor control is generally achieved by adding ingredients to the litter that either mask the odor or add compounds that are anti-bacterial, or other compounds that exhibit pleasant smell.
U.S. Pat. No. 3,675,625 to Miller et al. teaches a litter which is “activated” by heating and then contacted with an odor control agent, such as pine oil, citrus oil, camphor or the like.
U.S. Pat. No. 4,203,388 to Cortigene et al. teaches the use of a deodorant such as sodium bicarbonate, in amounts of between about 1% and about 10% of the dry weight of the litter. Such large amounts of deodorizer are necessitated since the litter itself is also used as an absorbent for urine, requiring the deodorizer to be homogeneously dispersed throughout the particles of the litter.
U.S. Pat. No. 4,405,354 to Thomas et al. discloses the use of buffering agents to prevent gaseous ammonia from escaping into the air. However, such buffering agents serve only to prevent the formation of gaseous ammonia; they are ineffective against other unpleasant odors. Further, the amounts of such agents range from about 0.5% to about 25% by weight, since all of the absorbent litter must be treated with the agent to provide sufficient contact with the urine.
U.S. Pat. No. 4,459,368 to Jaffee, et al. discloses particulate sorbing and deodorizing mixtures containing synthetic and clay sorbents. The composition contains sorbent fuller's earth clay particles and sorbent synthetic particles, e.g. calcium sulfate dihydrate-containing granules, in a weight ratio of about 0.5:9.5 to about 4:6, respectively. This combination of clay minerals and calcium sulfate dihydrate does not provide odor control.
U.S. Pat. No. 4,517,919 to Benjamin et al. discloses the use of undecylenic acid in amounts from about 1000 to about 10,000 ppm and a bacteriostat in amounts from about 25 to 500 ppm. U.S. Pat. No. 5,094,190 to Ratcliff et al. teaches an odor control animal litter to which a boron-containing liquid material has been applied.
U.S. Pat. No. 5,097,799 discloses odor control agents selected from the group consisting of guanidine salts, alkali metal fluorides, alkali metal bisulfites, and mixtures thereof. These agents are applied to the litter using an aqueous dispersion to produce an odor control animal litter.
U.S. Pat. No. 5,183,655 teaches an odor control animal litter that has applied to it an effective amount of pine oil in combination with an effective amount of boric acid.
U.S. Pat. No. 5,329,880 to Pattengill, et al. discloses clumpable animal litter. This waterproof litter contains a mixture of non-smectitic, hydrophilic shale aggregate with a fraction of coarse material with a size less than about 5 mesh (4000 microns). The mixture has the property of agglomerating into a clump upon contact with urine. The agglomerated clump of shale and urine is removable with a perforated scoop. The shale may contain up to 10 weight percent clumping agent selected from the group of water absorbent polymers, corn starch, gelatin, gluten and dried plants of the Plantago family. In addition 5 to 25 wt % ammonia absorbing zeolite may be added for odor control. The odor control agent is an absorbent for ammonia and does not provide odor control since ammonia is not immediately formed.
U.S. Pat. No. 5,634,431 to Reddy, et al. discloses odor inhibiting pet litter. The addition of urease negative bacteria to sodium smectite clay minerals in pet litter inhibits growth of urease positive bacteria for a period of several days, thereby retarding formation of ammonia and other obnoxious odors. Approximately fifty percent sodium bentonite in the litter causes the litter to clump upon wetting, maintaining the urea in contact with the treated clay and also serving as a buffer to favor growth of the urease negative bacteria. This composition entirely relies on inhibiting ammonia formation and does not provide immediately a pleasant scent.
U.S. Pat. No. 5,806,462 to Parr discloses clumping animal litter. The animal litter, is particularly for cats and has a gelatin solution and a dry adhesive sprayed onto the granules. The gelatin solution provides enough dampening to adhere the adhesive particles to the clay particles. Because the gelatin sets quickly, it does not provide so much wetting as to activate the adhesive. Therefore, the adhesive retains its adhesive properties and, together with the gelatin, causes the litter to clump when wetted by an animal. This clumping cat litter formulation provides no odor control.
U.S. Pat. No. 5,975,019 to Goss, et al. discloses clumping animal litter. The clumping animal litter utilizes the interparticle interaction of a sodium bentonite swelling clay with a non-swelling clay material. Preferably, sixty percent (60%) by weight, or less, composition of sodium bentonite is used after the judicious selection of particle size distribution such that the mean particle size of the non-swelling clay material is greater than the mean particle size of the sodium bentonite. In addition, an organic clumping agent, such as a pregelatinized corn starch can be combined with the sodium bentonite/clay mixture to enhance clumping properties. This clumping clay litter does not control odor.
U.S. Pat. No. 5,992,351 to Jenkins discloses clumpable animal litter with improved odor control. The clumpable animal litter with improved odor control comprises a) water-swellable clay particles capable of adhering other such particles upon contact with moisture; and b) an odor controlling-effective amount of a boron compound of a composition di-alkali metal tetraborate n-hydrate, wherein n is 4, 5 or 10, which controls odors arising from the contact of said clay particles with moisture.
U.S. Pat. No. 6,206,947 to Evans, et al. discloses a process for making an animal litter comprising gypsum, aluminum sulfate and urea. The animal litter composition is an agglomerated or compacted calcined calcium sulfate absorbent. The animal litter composition is screened to a particle size between 6 mesh and about 100 mesh and an effective amount of a binder such as a clay, lignin or starch is added to the calcium sulfate to assist the calcium sulfate to pelletize. This is a gypsum composition that is agglomerated using aluminum sulfate and urea to chemically combine with gypsum. There is no odor control in this clumping litter composition.
U.S. Pat. No. 6,253,710 to Ward, et al. discloses odor control for animal litter. It uses an odor control liquid and an aerosolized composition for deodorizing and controlling the odor of animal wastes. The liquid and aerosolized composition comprises a non-aqueous volatile carrier and an odor control agent. The liquid and aerosolized composition can be applied in liquid form directly to the animal litter and/or the animal container and/or the animal waste. The litter container may be sprayed with a powdered release agent which may be talc, of talc, inorganic silicone and magnesium powders, sodium bicarbonate, chlorophyll, sodium dihydrogen phosphate, potassium acid phthalates, or their mixtures preventing the stickiness of the odor controlling liquid. The liquid mixes with the litter product and always evaporating disseminates the odor control agent and is quickly exhausted.
There remains a need in the art for a cat or animal litter composition containing ingredients that release a pleasant scent after the cat or animal uses the litter, eliminating the malaise odor of common litter boxes.