[0001] The present invention relates to formulations for environmentally-friendly water-soluble zinc ricinoleate-based deodorizing concentrates.

Background Art

Zinc, and in particular zinc ricinoleate (zinc bis[(9Z,i2R)-i2-hydroxy-9-octadecenoate], see Figure 1) is well-known for its ability to form stable complexes with molecules containing electron-donating groups or atoms like nitrogen and sulfur. Materials which people perceive as malodors - urine, rotting flesh, body sweat, tobacco smoke, and such - comprise nitrogen- and sulfur-containing molecules, and as such, zinc ricinoleate acts as a very effective deodorizing agent for such malodors. Zinc ricinoleate is derived from castor oil, making it a popular component in environmentally-friendly deodorizing compositions.

[0002] However, because of the structure of zinc ricinoleate and its poor water solubility, in order to use zinc ricinoleate as a water-based deodorizing agent, additional agents are required to reshape the zinc ricinoleate molecule so that (a) the zinc is better exposed to form stable complexes with sulfur and/or nitrogen and (b) the hydroxyl groups in the ligand are exposed to the water to make the zinc ricinoleate more soluble. [0003] A number of attempts have been made to combine zinc ricinoleate with other materials to activate the zinc and to make the zinc ricinoleate water soluble. By way of example:

[0004] U.S. Pat. No. 6528047 discloses a deodorizing composition comprising zinc ricinoleate, a solubilizing agent (an alkoxylated amine), and water. [0005] U.S. Pat. No. 7226584 discloses a deodorizing composition comprising zinc ricinoleate, a solubility promoter (ionic or nonionic), and water.

[0006] U.S. Pat. No. 8318806 discloses a deodorizing composition comprising zinc ricinoleate, a solubility promoter (sodium iminodisuccinate), and water.

[0007] U.S. Pat. Pub. 20030199402 discloses a deodorizing composition comprising zinc ricinoleate, a surfactant (nonionic, cationic, anionic, amphoteric, or zwitterionic), a water dispersible polymer component (acrylate, polystyrene sulfonate, polycarboxylate, polyethylene amine, polyvinyl pyrrolidone, methylvinyl ether, polyvinyl alcohol, fluoropolymer), and water.

[0008] U.S. Pat. Pub. 20120321582 discloses a deodorizing composition comprising zinc ricinoleate, a chelating agent (such as sodium iminodisuccinate), a solubilizer (such as a combination of a vegetable-derived hydrophilic emollient ester, and a polyethylene derivative of hydrogenated castor oil), and water.

[0009] U.S. Pat. Pub. 20170216481 discloses a deodorizing composition comprising zinc ricinoleate, a chelating agent (several dozen examples), and water.

[0010] U.S. Pat. Pub. 20190365560 discloses a deodorizing composition comprising zinc ricinoleate, a surfactant (cocamidopropyl betaine), a chelating agent (citric acid), and water.

[0011] Bykov et al., Odour Absorption from Activated Zinc Ricinoleate, Personal Care Europe, pp. 124-128 (April 2020) discloses a deodorizing composition comprising zinc ricinoleate, a chelating agent (methylglycinediacetic acid trisodium salt or tetrasodium glutamate diacetate), and water. [0012] An ideal water-soluble zinc ricinoleate deodorizing concentrate would, at a minimum, (a) be clear, homogenous, and flowable, (b) would not form precipitates even after being stored at room temperature for at least two years, (c) would not require additional stabilizers or solubilizers when formulated into final products, (d) would have a high percentage (at least 15%) of activated zinc, and (e) would be environmentally friendly (e.g., no petroleum-derived ingredients). However, although each of the foregoing disclosed compositions purport to provide a water-soluble zinc ricinoleate deodorizing concentrate, to the best of the inventors’ knowledge, there are no compositions that exhibit all of the characteristics of the ideal water-soluble zinc ricinoleate deodorizing concentrate.

Summary of Invention

[0013] Embodiments of the present invention provide a liquid, environmentally- friendly, deodorizing concentrate comprising zinc ricinoleate, an amphoteric surfactant, an organic chelating agent, and a solvent. Embodiments of the present invention are (a) are clear, homogenous, and flowable, (b) do not form precipitates even after being stored at room temperature for at least two years, (c) do not require additional stabilizers or solubilizers when formulated into final products, (d) have a high percentage (at least 15%) of activated zinc, and (e) are environmentally friendly (e.g., no petroleum-derived ingredients).

Brief Description of the Drawings

[0014] Figure 1 shows the structure of zinc ricinoleate.

Detailed Description of the Invention

[0015] The amphoteric surfactant can be cocamidopropyl hydroxysultaine, cocamidopropyl betaine, or disodium cocoamphodiacetate, but preferably is cocamidopropyl hydroxysultaine. The organic chelating agent can be the trisodium salt of methylglycinediacetic acid (Na ₃ MGDA), or tetrasodium glutamate diacetate (GLDA), but preferably is Na ₃ MGDA. The solvent can be a glycol, glycol ether, or deionized water, but preferably is deionized water. The concentrate is, by weight, 0.1% to 60% zinc ricinoleate, 1% to 50% amphoteric surfactant, 1% to 30% organic chelating agent, and the balance solvent. One preferred embodiment of the concentrate is by weight, about 16% zinc ricinoleate, about 35% cocamidopropyl hydroxysultaine, about 20% trisodium salt of methylglycinediacetic acid, and about 29% deionized water.

[0016] Importantly, the components are all environmentally-friendly and there are no additional components required for a fully-functional deodorizing concentrate (although other components may be added for reasons other than obtaining water solubility and zinc activation).

[0017] As can be seen in Figure 1, the structure of zinc ricinoleate 100 is such that the zinc is somewhat shielded by the neighboring oxygens in the ligands. Further, because the hydroxy group in each ligand is somewhat folded over by the rest of the ligand, the molecule tends to be insoluble in water. Without limiting the embodiments of the present invention to any particular mechanism, the inventors believe that the specific choice of a surfactant, chelating agent, and solvent in the preferred embodiment helps (a) expose the zinc so that it is able to form stable complexes with nitrogen and/or sulfur in the malodor materials, and (b) unfolds the ligands to expose the hydroxy groups, allowing the zinc ricinoleate to be soluble in water. Further, and without limited the embodiments of the present invention to any particular mechanism, the inventors believe that the specific choice of an amphoteric surfactant, rather than an ionic, cationic, or non-ionic surfactant, keeps the concentrate clear, stable, and easily diluted in water and water-based ingredients to form a final product. Additional Embodiments

[0018] The inventive environmentally-friendly, deodorizing concentrate described in the foregoing embodiments of the present invention may be modified and/or extended by one of ordinary skill without departing from the spirit of the present invention, so long as the formulation (a) is clear, homogenous, and flowable, (b) does not form precipitates even after being stored at room temperature for at least two years, (c) does not require additional stabilizers or solubilizers when formulated into final products, (d) has a high percentage (at least 15%) of activated zinc, and (e) is environmentally friendly (e.g., no petroleum-derived ingredients).

[0019] In the foregoing embodiments, the amphoteric surfactant was cocamidopropyl hydroxysultaine, cocamidopropyl betaine, or disodium cocoamphodiacetate. Other embodiments could include utilize a different surfactant such as a 100% plant-derived or bio-based surfactant.

[0020] In the foregoing embodiments, the organic chelating agent was Na ₃ MGDA or GLDA. Other embodiments could utilize a different chelating agent such as a 100% plant-derived or bio-based chelating agent.

[0021] In the foregoing embodiments, the amphoteric surfactant and organic chelating agent were distinct components. Other embodiments could utilize a single component which acts both as a chelating agent and as a surfactant.

[0022] In the foregoing embodiments, the solvent was water or glycol. In other embodiments, the solvent could be another solvent chosen for its suitability for a particular application.

[0023] In addition to the zinc ricinoleate, an amphoteric surfactant, an organic chelating agent, and a solvent, the environmentally-friendly, deodorizing concentrate may include other common base components including colors, fragrances, and preservatives.