Compositions having ethyl levulinate and its mixtures with glycols and glycol ethers as fragrance carriers in air care applications

Abstract

A fragrance carrier composition includes a levulinic acid-based solvent and a glycol-based solvent. The fragrance carrier composition is a non-ideal mixture. A fragrance delivery system includes a fragrance delivery device. The fragrance delivery device includes a reservoir, a porous medium, and a diffuser. At least a portion of a first end of the porous medium is disposed in the reservoir and an opposite end of the porous medium is located proximate to a diffuser. The reservoir includes a fragrance and a fragrance carrier composition. A method for diffusing a fragrance into the air includes diffusing a fragrance from a fragrance solution into the atmosphere surrounding the fragrance delivery system. The fragrance solution includes a fragrance and a fragrance carrier composition.

Description

COMPOSITIONS HAVING ETHYL LEVULINATE AND ITS MIXTURES WITH GLYCOLS AND GLYCOL ETHERS AS FRAGRANCE CARRIERS IN AIR CARE APPLICATIONSBACKGROUND

[0001] This application claims priority to U.S. Provisional Patent Application 63 / 595,086, filed on November 1, 2023, the whole content of which is hereby incorporated herein by reference in its entirety for all purposes.

[0002] In fragrance delivery systems, porous wicks made of polymers are often partially submerged in a reservoir containing fragrance and a solvent, or a mixture of solvents. The solvent or mixture of solvents is used as a carrier to deliver the fragrance to a portion of the porous wick for diffusion into the atmosphere. As a result of wicking action in the porous media, the liquid mixture travels upward through the wick until the liquid front reaches a surface of the wick where it begins to evaporate and diffuse into the air in an order based on relative vapor pressure and local molar fraction at the liquid-gas interface. A heater, piezoelectric, or electrospray system are often implemented in the top of the wick to optimize the evaporation process.

[0003] Unfortunately, guaranteeing a constant liquid delivery in the top of the wick to maintain a constant fragrance delivery is often a challenge. Moreover, many solvents currently used as fragrance carriers are classified as VOC (volatile organic compounds), which increasingly present environmental and regulatory concerns.SUMMARY

[0004] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0005] In one aspect, embodiments disclosed herein relate to a fragrance carrier composition that includes a levulinic acid-based solvent and a glycol-based solvent. The fragrance carrier composition may be a non-ideal mixture.

[0006] In another aspect, embodiments herein relate to a fragrance delivery system that includes a fragrance delivery device. The fragrance delivery device includes a reservoir, a porous medium, and a diffuser. At least a portion of a first end of the porous medium is disposed in the reservoir and an opposite end of the porous medium is located proximate to a diffuser. The reservoir includes a fragrance and a fragrance carrier composition.

[0007] In another aspect, embodiments herein relate to a method for diffusing a fragrance into the air, which includes diffusing a fragrance from a fragrance solution into the atmosphere surrounding the fragrance delivery system. The fragrance solution includes a fragrance and a fragrance carrier composition.

[0008] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1A shows a comparison of Infrared spectra (absorbance) of pure ethyl levulinate (EL), pure butylene glycol (BG) and the binary mixture (1 :1, w / w) of these solvents.

[0010] FIG. IB shows a comparison of Infrared spectra (absorbance) of pure ethyl levulinate (EL), pure tripropylene glycol monomethyl ether (TPM) and the binary mixture (1 :1, w / w) of these solvents.

[0011] FIG. 1C shows a comparison of Infrared spectra (absorbance) of pure ethyl levulinate (EL), pure dipropylene glycol (DPG) and the binary mixture (1 : 1, w / w) of these solvents.

[0012] FIG. 2A shows a scheme of a polymeric wick immersed in a reservoir in accordance with one or more embodiments.

[0013] FIG. 2B shows a liquid sensitive paper for time tracking in accordance with one or more embodiments.

[0014] FIG. 3A is a graph of the experimental dynamic viscosity (r ) variation at 25°C of binary blends using butylene glycol (BG) as the base (“heavier”) solvent and different weight fractions (Xi) of a “lighter” solvent.

[0015] FIG. 3B is a graph of the deviation of experimental viscosity from the theoretical viscosity of an ideal binary mixture of mixtures presented in FIG. 3 A.

[0016] FIG. 4A is a graph of the experimental dynamic viscosity (r ) variation at 25°C of binary blends using tripropylene glycol monomethyl ether (TPM) as the base (“heavier”) solvent and different weight fractions (Xi) of a “lighter” solvent.

[0017] FIG. 4B is a graph of the deviation of experimental viscosity from the theoretical viscosity of an ideal binary mixture of mixtures presented in FIG. 4A.

[0018] FIG. 5A is a graph of the experimental dynamic viscosity (r ) variation at 25 °C of binary blends using dipropylene glycol (DPG) as the base (“heavier”) solvent and different weight fractions (Xi) of a “lighter” solvent.

[0019] FIG. 5B is a graph of the deviation of experimental viscosity from the theoretical viscosity of an ideal binary mixture of mixtures presented in FIG. 5A.

[0020] FIG. 6 is a graph of the diffusion velocity / dynamic viscosity ratio in the wick of binary blends using butylene glycol (BG) as the base (“heavier”) solvent at room temperature and different weight fractions (Xi) with a “lighter” solvent.

[0021] FIG. 7 is a graph of the diffusion velocity / dynamic viscosity ratio in the wick of binary blends using TPM as the base (“heavier”) solvent at room temperature and different weight fractions (Xi) of a “lighter” solvent.

[0022] FIG. 8 is a graph of the diffusion velocity / dynamic viscosity ratio in the wick of binary blends using DPG as the base (“heavier”) solvent at room temperature and different weight fractions (Xi) of a “lighter” solvent.DETAILED DESCRIPTION

[0023] Embodiments of the present disclosure relate to compositions used in air care applications as fragrance carriers. In particular, embodiments of the present disclosurerelate to compositions containing levulinic acid-based solvents as a carrier for fragrances. Advantageously, compositions containing levulinic acid-based solvents can reduce the viscosity of glycols and glycol ethers in mixtures to a greater degree than previously anticipated, and in fact, levulinic acid-based solvents can reduce the viscosity of glycols and glycol ethers in mixtures to a greater degree than one of ordinary skill in the art would have anticipated or predicted. This is due to levulinic acid-based solvents surprisingly demonstrating non-ideal behavior in binary mixtures, including when levulinic acid-based solvents are combined with glycols and glycol ethers in mixtures. When low viscosity mixtures are used as fragrance carrier compositions, it is possible to obtain a faster diffusion through a porous wick and, consequently, keep a constant delivery of the fragrance in the wick top for the evaporation process to happen. In contrast, glycol-based solvents present high surface-energies and, consequently, high viscosity, challenges arise when glycol and glycol ethers are used as a fragrance carrier. Such challenges include guaranteeing a constant liquid delivery in the top of the wick to keep constant delivery of a fragrance. According to Darcy’s law, the fluid flow in porous media has an inverse correlation with viscosity, making the reduction of the carrier viscosity an important parameter to adjust in order to guarantee constant fragrance delivery. Advantageously, this lower viscosity is achieved when using levulinic acid-based solvents, such as ethyl levulinate.

[0024] Additionally, since levulinic acid-based solvents surprisingly demonstrate nonideal behavior, this unexpectedly allows for blends or mixtures of a levulinic acid-based solvent and a glycol -based solvent to not only have a lower viscosity as compared to the glycol-based solvent alone, but can allow for higher amounts of the glycol-based solvent to be used, while still providing acceptable viscosity properties. Similarly, since levulinic acid-based solvents surprisingly demonstrate non-ideal behavior, this also unexpectedly allows for blends or mixtures of a levulinic acid-based solvent and a glycol-based solvent that can have lower amounts of the levulinic acid-based solvent in the blend or mixture, while still providing acceptable viscosity properties.

[0025] Further, many fragrance carriers are classified as VOCs, which are increasingly of environmental and regulatory concern. Some traditional fragrance carrier solvents areclassified as low vapor pressure VOCs, which are solvents having vapor pressures lower than 0.1 mmHg (millimeters of mercury) at 20 °C. For example, traditional carrier solvents DBE™ LVP (available from Invista), dipropylene glycol methyl ether acetate (DPMA), and isopropylideneglycerol (IPG) have vapor pressures at 20 °C of 0.04 mmHg, 0.08 mmHg, and 0.04 mmHg, respectively. Advantageously, ethyl levulinate is a low vapor pressure-VOC class solvent with a higher vapor pressure than traditional solvents used in air care applications, advantageously allowing for reduction of temperature in the air care devices, energy savings, maintenance of evaporation rate, and meeting environmental and regulatory requirements.

[0026] Generally, optimizing the flow and transport of multiple components in liquid mixtures through porous media has a broad range of applications in the air care market due to the broad use of porous wicks in fragrance delivery systems. While glycol-based solvents can be used in air care applications, delivering liquid in a continuous manner to the top of a cylindrical porous wick from a bottom end of the wick that is disposed in a fragrance reservoir is a particular challenge. These glycol-based solvents include glycols and glycol ethers. As noted above, glycol-based solvents generally have high surfaceenergies and high viscosity, which lead to an inconsistent delivery of a fragrance to the top end of a porous wick.

[0027] As the fluid flow in porous media has an inverse correlation with viscosity according to Darcy’s law, the carrier viscosity of glycol -based solvents is an important parameter to control in order to ensure constant and consistent fragrance delivery in many air care systems. Thus, there remains a need to develop fragrance carrier compositions using only low vapor pressure-VOCs, notably for constant fragrance delivery for use in air care devices including liquid electrical air fresheners, such as heated wick delivery systems (e.g., low temperature devices including low temperature liquid electrical air fresheners), piezoelectric spraying systems, electrospray devices, aerosol diffusers, Venturi devices, or wicking devices (e.g., reed diffusers).

[0028] One or more embodiments herein relate to the use of solvent mixtures as fragrance carrier compositions to reduce the viscosity of glycol-based solvents and increase the rateof diffusion in porous media. In some embodiments, a solvent mixture includes a binary mixture of a glycol-based solvent and a levulinic acid-based solvent. The additional levulinic acid-based solvent may be a less viscous solvent as compared to the glycol-based solvent. The fragrance carrier composition of one or more embodiments may be used in a fragrance delivery system.

[0029] FRAGRANCE CARRIER COMPOSITION

[0030] In one aspect, embodiments disclosed herein relate to a fragrance carrier composition. The fragrance carrier composition may include levulinic acid-based solvent. The fragrance carrier composition may include a glycol-based solvent and a levulinic acidbased solvent. The fragrance carrier composition of one or more embodiments may include a weight ratio (w / w) of levulinic acid-based solvent to the glycol -based solvent in a range from 1 :99 to 100:0 w / w. The fragrance carrier composition of one or more embodiments may include a weight ratio (w / w) of levulinic acid-based solvent to the glycol -based solvent in a range from 10:90 to 100:0 w / w. In some embodiments, the fragrance carrier composition having non ideal behavior includes a binary mixture of levulinic acid-based solvent and a glycol-based solvent in a weight ratio (w / w) in a range from 1 :99 to 99:1 w / w. The fragrance carrier composition having non ideal behavior may include a binary mixture of levulinic acid-based solvent and a glycol -based solvent in a weight ratio (w / w) in a range from 10:90 to 99: 1 w / w. The fragrance carrier composition of one or more embodiments may include a ratio of levulinic acid-based solvent to the glycol-based solvent in a range with a lower limit from 1 :99, 5:95, 10:90, 20:80, 25:75, 30:70, 40:60, and 45:55 w / w with an upper limit of any one of 50:50, 55:45, 60:40, 70:30, 75:25, 80:20, 85: 15, 9:91, 95:5, 99: 1, and 100:0 vi / vi, where any lower limit can be paired with any mathematically compatible upper limit.

[0031] The levulinic acid-based solvent may have a viscosity lower than a viscosity of the glycol-based solvent such that a mixture of the levulinic acid-based solvent and the glycol- based solvent have a reduced viscosity as compared to the glycol-based solvent. The levulinic acid-based solvent may have a viscosity lower than a viscosity of the glycol -based solvent such that a mixture of the levulinic acid-based solvent and the glycol-based solventhas non-ideal behavior. The mixture of the levulinic acid-based solvent and the glycol- based solvent may have non-ideal behavior in a binary mixture. The term “non-ideal behavior” refers to a mixture of liquids having an experimental viscosity that deviates from a theoretical viscosity of the mixture. In mixtures with non-ideal behavior (i.e., non-ideal mixtures), molecules (e.g., fragrance molecules, solvent molecules, or both) may interact differently as compared to molecules in the pure solvents or in ideal mixtures due to changes intermolecular forces of the mixture as compared to the pure solvents.

[0032] The fragrance carrier composition may have a difference in theoretical viscosity and experimental viscosity greater than 15 milliPascals- seconds (mPa s). In some embodiments, the fragrance carrier composition has a difference in theoretical viscosity and experimental viscosity greater than 20 mPa s. The fragrance carrier composition may have a difference in theoretical viscosity and experimental viscosity greater than 25 mPa s. The fragrance carrier composition may have a difference in theoretical viscosity and experimental viscosity greater than 30 mPa s. The fragrance carrier composition may have a difference in theoretical viscosity and experimental viscosity greater than 35 mPa s. The fragrance carrier composition may have a difference in theoretical viscosity and theoretical viscosity greater than 40 mPa s.

[0033] In some embodiments, the levulinic acid-based solvent is selected to decrease the viscosity of the glycol-based solvent when the levulinic acid-based solvent and the glycol- based solvent are mixed. The resulting reduced viscosity of the mixture of the levulinic acid-based solvent and the glycol-based solvent may be selected to increase a diffusion rate through a porous medium as compared to a diffusion rate through a porous medium of only a glycol-based solvent. The glycol-based solvent may include one or more selected from glycols and glycol ethers. In some embodiments, glycols include a compound selected from a group consisting of butylene glycol, tripropylene glycol methyl ether, dipropylene glycol, propyleneglycol, 1,2-pentanediol, 1,4-pentanediol, and combinations thereof.

[0034] In embodiments in which the glycol-based solvent includes tripropylene glycol methyl ether (TPM), the difference in theoretical viscosity and experimental viscosity may be greater than 0.5 mPa s. In such embodiments, the difference in theoretical viscosity andexperimental viscosity is greater than 0.55 mPa s. The difference in theoretical viscosity and experimental viscosity may be greater than 0.6 mPa s. The difference in theoretical viscosity and experimental viscosity may be greater than 0.65 mPa s. The difference in theoretical viscosity and experimental viscosity may be greater than 0.7 mPa s. The difference in theoretical viscosity and experimental viscosity may be greater than 0.75 mPa s. The difference in theoretical viscosity and experimental viscosity is greater than 0.8 mPa s.

[0035] The levulinic acid-based solvent may include a functionalized structure of levulinic acid. The structure of levulinic acid is as shown below in Formula (I):Formula (I).

[0036] In some embodiments, one or more atoms of the levulinic acid structure is functionalized. The functionalization of levulinic acid may include covalent bonding one or more of the carbons on the hydrocarbon chain, esterification of the carboxylic acid group, substitution of the ketone group, ionization of the carboxylic acid group, or combinations thereof. The levulinic acid-based solvent of one or more embodiments may be an ester. For example, the levulinic acid-based solvent may include an ester of levulinic acid. In some embodiments, the ester of levulinic acid solvent has a general structure represented by Formula (II).Formula (II) wherein R may be a Ci-Cio hydrocarbon group. In some embodiments, R is a hydrocarbon group and includes carbon atoms in a range having a lower limit of any one of 1, 2, and 3 carbons and an upper limit of any one of 3, 4, 5, 6, 7, 8, 9, and 10 carbons, where any lower limit can be paired with any mathematically compatible upper limit. In one or moreparticular embodiments, R is a C1-C10 hydrocarbon group, preferably a Ci-Ce hydrocarbon group, including a C1-C10 alkyl or alkenyl group, preferably a Ci-Ce alkyl or alkenyl group. In some embodiments, R is preferably a C2-C6 hydrocarbon group, including a C2-C6 alkyl or alkenyl group, more preferably a C2-C3 hydrocarbon group, including an ethyl group, butyl group, and mixtures thereof. In some embodiments, R may be a saturated or unsaturated hydrocarbon group. In certain embodiments, the levulinic acid-based solvent can comprise at least 90 wt. % of the ester of levulinic acid solvent of Formula (II). In particularly preferred embodiments, the levulinic acid-based solvent can comprise at least 95 wt. %, including at least 98 wt. % of the ester of levulinic acid solvent of Formula (II).

[0037] In one or more particular embodiments, the levulinic acid-based solvent includes ethyl levulinate, which is as shown in Formula (III):Formula (III).

[0038] The levulinic acid-based solvent may consist essentially of ethyl levulinate such that the non-ideal nature of the fragrance carrier composition is maintained. For example, the levulinic acid-based solvent consisting essentially of ethyl levulinate can include one or more additional compounds that do not materially affect or alter the non-ideal nature of the fragrance carrier composition. In such embodiments, the non-ideal nature of the fragrance carrier composition is present with a levulinic acid-based solvent consisting essentially of ethyl levulinate. In certain embodiments, the levulinic acid-based solvent can comprise at least 90 wt. % of ethyl levulinate. In particularly preferred embodiments, the levulinic acid-based solvent can comprise at least 95 wt. %, including at least 98 wt. % of ethyl levulinate.

[0039] The levulinic acid-based solvent may have a higher vapor pressure as compared to traditional low vapor pressure VOC solvents used in air care devices. In some embodiments, the levulinic acid-based solvent has a vapor pressure value at 20 °C selected from a range from 0.085 mmHg to 0.20 mmHg. In some embodiments, the levulinic acid-based solvent has a vapor pressure value at 20 °C selected from a range with a lower limit of any one of 0.085, 0.086, 0.087, and 0.09 mmHg and an upper limit of any one of 0.09, 0.091, 0.092, 0.095, 0.10, 0.12, 0.15, 0.18, and 0.20 mmHg, where any lower limit can be paired with any mathematically compatible upper limit. The levulinic acid-based solvent may have a vapor pressure value of 0.2 mmHg or less at 20 °C. The levulinic acid-based solvent may have a vapor pressure value at 20 °C of 0.15 mmHg or less. The levulinic acidbased solvent may have a vapor pressure value at 20 °C of 0.10 mmHg or less. In one or more particular embodiments, the levulinic acid-based solvent has a vapor pressure value at 20 °C of 0.09 mmHg or less. In some embodiments, the levulinic acid-based solvent has a vapor pressure value at 20 °C selected from a range from 0.085 mmHg to 0.095 mmHg. In some embodiments, the levulinic acid-based solvent includes methyl levulinate, which has a vapor pressure value of 0.15 mmHg at 20 °C. The levulinic acid-based solvent may include ethyl levulinate, which has a vapor pressure value of 0.09 mmHg at 20 °C.

[0040] The fragrance carrier composition may have a vapor pressure value at 20 °C in a range from 0.010 mmHg to 0.095 mmHg. In some embodiments, the fragrance carrier composition has a vapor pressure value selected from a range with a lower limit of any one of 0.010, 0.012, 0.015, 0.020, 0.25, 0.5, 0.75, 0.085, 0.086, 0.087, and 0.09 mmHg and an upper limit of any one of 0.5, 0.75, 0.085, 0.086, 0.087, 0.09, 0.091, 0.092, and 0.095 mmHg at 20 °C, where a lower limit can be paired with a mathematically compatible upper limit.

[0041] In some embodiments, the fragrance carrier composition has a wick diffusion rate (or a “diffusion velocity”) of at least 2.5 millimeters per minute (mm / min) through a polymeric material. In some embodiments, the polymeric material includes one or more selected from PET, polypropylene, polyethylene, and cellulose. The fragrance carrier composition may have a wick diffusion rate of at least 4 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 5 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 7.5 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 10 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 12mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 15 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 20 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 25 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 30 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 35 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 40 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 45 mm / min through a polymeric material. The fragrance carrier composition may have a wick diffusion rate of at least 50 mm / min through a polymeric material.

[0042] FRAGRANCE DELIVERY SYSTEM

[0043] In another aspect, embodiments herein relate to a fragrance delivery system. In some embodiments, the fragrance delivery system includes a fragrance delivery device that includes a reservoir, a porous medium, and a diffuser. The fragrance delivery system of one or more embodiments may be an air care device including one or more selected from a heated wick delivery system, a piezoelectric spraying system, an electrospray system, an aerosol device that includes an aerosol diffuser, a Venturi device, or a wicking device.

[0044] As one of ordinary skill may appreciate, the fragrance delivery system may include a power supply configured to power the diffuser of the fragrance delivery device such that the diffuser may have sufficient power to operate and diffuse the fragrance from the fragrance carrier composition to the atmosphere. In some embodiments, the fragrance delivery system includes one or more electrical connections configured couple the fragrance delivery system to an electrical power source. In such embodiments, the electrical power source coupled to the fragrancy delivery system is configured to assist in the diffusion of the fragrance from the fragrance carrier composition to the atmosphere.

[0045] The diffuser of the fragrance delivery device may be configured to diffuse a fragrant compound from a fragrance solution. The fragrance solution may be present in the reservoirof the fragrance delivery device. The fragrance solution may be a fragrance mixture that includes a fragrance and a fragrance carrier composition. The fragrance carrier composition may be as described above. The fragrance may be a compound that is soluble in levulinic acid-based solvents, glycol-based solvents, or both. In such embodiments, the fragrance may be an essential oil. The fragrance may be a compound having a vapor pressure in a range from 0.05 to 1.5 mmHg at 20 °C. The fragrance may be a compound having a vapor pressure value at 20 °C selected from a range with a lower limit of any one of 0.05, 0.06, 0.065, 0.7, 0.075, 0.10, 0.15, 0.25, 0.5, and 0.75 mmHg and an upper limit of any one of 0.12, 0.15, 0.20, 0.25, 0.30, 0.50, 0.65, 0.75, 0.80, 0.90, 0.95, 0.98, 1.0, 1.05, 1.10, 1.15, 1.20, and 1.50 mmHg, where any lower limit can be paired with any mathematically compatible upper limit. In some embodiments, the fragrance may preferably be a compound having a vapor pressure value selected from a range from 0.1 to 0.9 mmHg at 20 °C, more preferably from a range from 0.1 to 0.75 mmHg at 20 °C..

[0046] The fragrance solution may include the fragrance in an amount such that the fragrance carrier composition maintains its form as a non-deal mixture. The fragrance may include the fragrance in amount such that the non-ideal behavior of the fragrance carrier composition is maintained. In some embodiments, the fragrance solution includes the fragrance and the fragrance carrier composition at a ratio in a range having a lower limit of any one of 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 50:50, and 60:40 w / w and an upper limit of any one of 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 60:40, and 65:35 w / w. Non-limiting examples of fragrance solutions for a plugin diffuser fragrance delivery system may include fragrance and the fragrance carrier composition in a range from 60:40 to 40:60 w / w. Non -limiting examples of fragrance solutions for a passive diffuser fragrance deliver system may include fragrance and the fragrance carrier composition in a range from 10:90 to 30:70 w / w. The fragrance solution may include the fragrance in an amount such that the fragrance delivery system continuously delivers fragrance for at least 2 weeks, including at least 3 weeks, and preferably at least 4 weeks.

[0047] The diffuser may be configured to diffuse a fragrance from a fragrance solution that has passed from the reservoir through a first end of a porous medium to a top end of theporous medium. In some embodiments, the diffuser includes a heater, a piezoelectric spraying system, an electrospray system, a reed diffuser stick, or combinations thereof.

[0048] The porous medium may have an elongated shape. In such embodiments, the porous medium may have at least a first end and a second end. The porous medium having an elongated shape may be flat, circular, or combinations thereof. The porous medium may have top end located proximate to a diffuser and a bottom end disposed in the reservoir of the fragrance delivery device. The diffuser may be coupled to the reservoir. The porous medium of the fragrance delivery device may be a wick, a reed diffuser stick, or combinations thereof. In some embodiments, the porous medium includes a polymeric material. The polymeric material may include one or more selected from PET, polypropylene, polyethylene, cellulose, among other polymers.

[0049] Embodiments in which the porous medium includes a reed diffuser stick, the material of the reed diffuser stick may be the diffuser. In such embodiments, the reed diffuser stick may be disposed in a reservoir having an opening for the top end of the reed diffuser stick to pass through. The top end of the reed diffuser stick may sufficiently diffuse a fragrance from a solution in the reservoir to the atmosphere. In embodiments in which the porous medium includes a wick, the wick may include a polymeric material including, but not limited, to polyethylene terephthalate (PET). In one or more embodiments, at least a portion of the first end of the porous medium is disposed in a solution of the reservoir of the fragrance delivery device.

[0050] METHOD FOR DELIVERING A FRAGRANCE

[0051] In another aspect, embodiments herein relate to a method for delivering a fragrance to the atmosphere. The method may include preparing a fragrance solution comprising a fragrance and a fragrance carrier composition in a fragrance delivery system. The fragrance carrier composition and the fragrance delivery system may be as described above.

[0052] Preparing the fragrance solution may include adding a fragrance to the fragrance carrier composition to form the fragrance solution. In such embodiments, the fragrance solution may be prepared in a reservoir of a fragrance delivery system. In some embodiments, the fragrance solution may be prepared and then added to the reservoir ofthe fragrance delivery system. The method of one or more embodiments may include reducing the viscosity of a glycol-based solvent by adding a levulinic acid-based solvent to the glycol-based solvent.

[0053] The thermodynamic characteristics of the fragrance carrier composition of one or more embodiments may be characterized through one or more analytical processes, including, but not limited to, spectroscopic analysis. Spectroscopic analysis may include infrared spectroscopy (e.g., Fourier-transform Infrared spectroscopy) coupled with a attenuated total reflectance (ATR) sample chamber (e.g., an ATR crystal). As one of ordinary skill may appreciate, infrared (IR) light shines on a sample in the sample chamber and interacts with it. The IR light that has interacted with the sample is then detected to create a Fourier-transform infrared (FT-IR) spectrum, which is unique for each sample and can be used to identify, characterize, and quantify the different substances that are present in the sample. The fragrance carrier compositions having non-ideal behavior that are characterized with IR-ATR may have spectra with shifted bands, bands with different shapes, or both as compared to the IR-ATR spectra of pure solvents. These changes may be indicative of changes in intermolecular forces, thereby indicating non-ideal behavior in solvent blends. For example, the IR-ATR spectra of the fragrance carrier composition of one or more embodiments may have changes in spectral bands that correspond to changes in hydrogen bonding of the mixtures as compared to the hydrogen bonds of the pure solvents.

[0054] In some embodiments, the method includes determining the difference in theoretical and experimental viscosities of a fragrance carrier composition. The difference in theoretical and experimental viscosities of a fragrance carrier composition may indicate that the fragrance carrier composition has non-ideal behavior.

[0055] In some embodiments, the method may include passing the fragrance solution from a first end of a porous medium disposed in a reservoir of a fragrance delivery system through a porous medium to a second end of the porous medium. The fragrance solution may pass from the first end of the porous medium to the second end of the porous medium at a constant rate. In one or more particular embodiments, the levulinic acid-based solventof the fragrance carrier composition increases a rate of diffusion of the fragrance carrier composition through the porous medium as compared to a rate of diffusion of the glycol- based solvent through the porous medium. The porous medium may include one or more polymeric materials as described above.

[0056] In one or more embodiments, the second end of the porous medium can be located proximate to a diffuser that may be coupled to a power source. In such embodiments, operating the diffuser promotes the diffusion of the fragrance from the fragrance solution in the second end of the porous medium to the atmosphere. In one or more embodiments, the fragrance is diffused from the fragrance solution into the atmosphere surrounding the fragrance delivery system, thereby delivering the fragrance to the atmosphere.

[0057] The method of one or more embodiments may include determining a wick diffusion rate of the fragrance carrier composition. In such embodiments, the diffusion rate of a solvent blend is determined by measuring the time it takes for a solvent front to travel from a bottom end of a wick disposed in a solvent reservoir to the top end of the wick. The method of one or more embodiments may include determining if the fragrance carrier composition is a non-ideal mixture. In such embodiments, the method of one or more embodiments may include determining a difference in theoretical viscosity and experimental viscosity of a fragrance carrier composition. In such embodiments, an experimental viscosity may be determined by measuring the viscosity of a solvent blend, such as with a Viscometer Anton Paar SVM 3001. The theoretical dynamic viscosity may be determined by Equation (1). heo = ^=i Xi. T]i Equation (1) where ntheois the theoretical dynamic viscosity of a solvent blend; xi is the molar fraction of the pure component i; and T]i is the dynamic viscosity of the pure component i.

[0058] One or more embodiments herein relates to the use of levulinic acid-based solvents, such as ethyl levulinate and its mixtures to solubilize and / or carry fragrances. Notably, for the use in air care devices, liquid electrical air fresheners, such as a heated wick delivery systems, piezoelectric spraying systems, electrospray devices, Venturi devices or wicking devices as reed diffusers. The key element of the invention relies on the unique andoptimized transportation behavior of the ethyl levulinate and its mixtures with glycols and glycols ethers in the porous media normally used in fragrance delivery systems. The ethyl levulinate notably reduces the viscosity of glycols and glycol ethers in mixtures composition, presenting a non-ideal behavior in binary mixture. The reduced viscosity drives to a faster diffusion of the mixture in the devices, allowing an optimized and constant fragrance delivery.

[0059] EXAMPLES

[0060] The performance of the ethyl levulinate to reduce the viscosity and increase the diffusion in the porous wick in ethyl levulinate in binary mixtures with butylene glycol, tripropylene glycol methyl ether, and dipropylene glycol were compared with other light solvents used for the same purpose in air care. It was observed experimentally that viscosity was reduced in blends glycols and glycol ethers with ethyl levulinate as compared to solvents with isopropylideneglycerol (IPG), dipropylene glycol methyl ether acetate (DPMA) and dipropylene glycol monomethyl ether (DPM). It was observed that binary systems having ethyl levulinate and butylene glycol, ethyl levulinate and tripropylene glycol monomethyl ether, and ethyl levulinate and dipropylene glycol presented deviations from ideal mixtures and lower viscosity values when compared with other solvents that are normally used as fragrance carriers.

[0061] Materials

[0062] Butylene glycol (BG), dipropylene glycol methyl ether acetate (DPMA), dimethyl glutarate, dimethyl adipate, ethyl levulinate (EL), dipropylene glycol monomethyl ether (DPM) were all obtained from Sigma-Aldrich. Tripropylene glycol methyl ether (TPM) was obtained from Dow Chemicals. Isopropylideneglycerol (IPG) was obtained from Solvay. Dipropylene glycol (DPG) was obtained from Thermo Scientific. Dimethyl glutarate (DMG) and dimethyl adipate (DMA) were used to prepare a synthetic mixture (DMG / DMA) to mimic the commercial solvent DBE ™ LVP (available from Invista).

[0063] Example 1 : Spectroscopic characterization of binary mixtures

[0064] Fourier-transform Infrared Spectroscopy (FTIR) was used to analyze pure samples of EL, BG, TPM, and DPG, along with 1 : 1 w / w blends of EL:BG, EL:TPM, and EL:DPG. FTIR spectra for each sample was acquired on a Bruker ALPHA II compact FT-IR spectrometer coupled to an ATR crystal. For each of the pure solvents and binary mixtures analysis, three (3) drops of the sample was placed in the ATR crystal of the Bruker ALPHA II instrument, and the absorbance was obtained from 600 cm'1to 4000 cm'1. IR spectra for pure solvents and blends are presented in FIGs. 1 A-1C.

[0065] As shown in FIGs. 1 A to 1C, the spectra recorded for pure glycol and glycol ethers show a broad band that dominates the region from 3650 cm'1to 3200 cm'1, the location and shape of which corresponds to a noticeable hydroxyl group and indicates the presence of hydrogen bonding between molecules of glycols / glycols ethers in their pure state. Other characteristic peaks correspond to C-H vibrations and C-0 vibrations for hydroxyl groups in the pure solvents. In the case of the EL, it is possible to identify a sharp band at 1723 cm'1, which is characteristic of the presence of C=O functional group, as well a strong band in 1159 cm'1corresponding to C-O-C vibration.

[0066] In each spectrum recorded for the binary mixtures, the characteristic O-H band is shifted to higher frequencies compared to pure glycols / glycol ether (e.g., from 3316 cm'1for pure BG to 3355 cm'1in a mixture with EL (FIG. 1 A); from 3472 cm'1for pure TPM to 3480 cm'1in a mixture with EL (FIG. IB); and from 3350 cm'1for pure DPG to 3423 cm'1in a mixture with EL). In each blend, the O-H band significantly changed shape and absorption maximum value, indicating that interm olecul ar hydrogen bonds present in the mixtures are weaker compared to the ones present in pure glycols / glycol ethers. Accordingly, a lower viscosity (e.g., negative change in experimental viscosity from theoretical viscosity (Aq)) than expected is observed for binary mixtures between ethyl levulinate and glycol / glycol ether (e.g., as presented in Tables 6, 11, and 16), which characterizes EL / BG, EL / TPM, and EL / DPG as non-ideal binary mixtures.

[0067] Example 2:

[0068] A variety of blends were prepared according to the weight ratios (w / w) and concentrations presented in Table 1.

[0069] Table 1: Blends composition.* Prepared with 73% by weight of dimethyl glutarate (DMG) and 27% by weight of dimethyl adipate (DMA).

[0070] Example 3 : Measuring wick diffusion velocity.

[0071] The wick diffusion velocity in millimeters per second (mm / s) of each of the sample mixtures 1 through 53 prepared according to Table 1 were measured using a standard wick of Polyethylene terephthalate (PET, dimensions: length: 76 mm; diameter: 7 mm). The method of measuring the wick diffusion velocity included adding 3.5 g of the blend in a bottle as shown in FIG. 2A. The PET wick was attached to the system by immersing a portion of the bottom end of the wick in the blend to avoid radial penetration. At this moment, a chronometer was initialized. Every 30 seconds, the system was evaluated for wick saturation by determining if the blend had reached the top end of the wick by contacting a liquid sensitive paper with the top of the wick as shown in FIG. 2B. When a full circular spot was observed on the liquid sensitive paper, the time on the chronometer was recorded and the total time (min, minutes) was determined.

[0072] Example 4: Measuring viscosity of the blends

[0073] The dynamic viscosity (in milliPascals- seconds, mPa- s) and kinematic viscosity (in millimeters squared per second (mm2 / s) of a portion of each of samples 1 through 53 listed in Table 1 were measured with a Viscometer Anton Paar SVM 3001 and recorded. In this viscometer, the viscosity measuring cell includes a tube that rotates at constant speed and is filled with sample fluid while a measuring rotor with a built-in magnet floats in the sample. The sample’s shear forces drive the rotor while magnetic forces delay its rotation. When the rotor reaches equilibrium speed, the fluid’s viscosity is determined. The kinematic viscosity is calculated from the dynamic viscosity and density of the sample.

[0074] The equipment was purged with 2 mL (milliliters) of each sample before the measurement using a 5 mL syringe. After purging, 1 mL of sample was added in the equipment using the same syringe and the viscosities and density measurement was performed automatically. Recorded dynamic viscosity (milliPascals seconds, mPa s), density (grams per cubic centimeter, g / cm3), and calculated kinematic viscosity (millimeters squared per second, mm2 / s) of samples 1-53 are presented in Table 2 along with the time to wick diffusion (in minutes, min).

[0075] Table 2 Viscosity, density and time to complete wick diffusion.

[0076] Example 5 : Calculation of the change in experimental and theoretical viscosity

[0077] Since the experimental viscosity was obtained for most of the samples as shown in Table 2, it was possible to calculate the difference between the experimental and theoretical viscosity (Ar|) to determine the deviation from ideal behavior of the mixture. Additionally, the sample diffusion through the PET wick was calculated in millimeters per minute (mm / min). Tables 3 through 16 present these values for each solvent blend listed in Tables 1 and 2.

[0078] Tables 3. Dynamic viscosity, viscosity deviation and wick diffusion for IPG / BG blends.

[0079] Table 4. Dynamic viscosity, viscosity deviation and wick diffusion for DPMA / BG blends.

[0080] Table 5. Dynamic viscosity, viscosity deviation and wick diffusion for DPM / BG blends.

[0081] Table 6. Dynamic viscosity, viscosity deviation and wick diffusion for EL / BG blends.

[0082] Table 7. Dynamic viscosity, viscosity deviation and wick diffusion forDMG / DMA / TPM blends.

[0083] Table 8. Dynamic viscosity, viscosity deviation and wick diffusion for IPG / TPM blends.

[0084] Table 9. Dynamic viscosity, viscosity deviation and wick diffusion for DPMA / TPM blends.

[0085] Table 10. Dynamic viscosity, viscosity deviation and wick diffusion for DPM / TPM blends.

[0086] Table 11. Dynamic viscosity, viscosity deviation and wick diffusion for EL / TPM blends.

[0087] Table 12. Dynamic viscosity, viscosity deviation and wick diffusion forDMG / DMA / DPG blends.

[0088] Table 13. Dynamic viscosity, viscosity deviation and wick diffusion for IPG / DPG blends.

[0089] Table 14. Dynamic viscosity, viscosity deviation and wick diffusion for DPMA / DPG blends.

[0090] Table 15. Dynamic viscosity, viscosity deviation and wick diffusion for DPM / DPG blends.

[0091] Table 16. Dynamic viscosity, viscosity deviation and wick diffusion for EL / DPG blends.

[0092] As shown in Tables 3 through 16 and FIGS. 3A through 5B, blends of solvents containing ethyl levulinate surprisingly have a reduction in viscosity versus what the expected, or theoretical, viscosity should be. Notably, blends of ethyl levulinate with butylene glycol, TPM, and DPG unexpectedly resulted in a faster wick diffusion rate and greater deviation from ideal behavior of the mixtures as compared to commercial solvent products used in air fresheners (i.e., DBE™ LVP, IPG, DPMA and DPM). Thus, the data above indicate that binary solvent blends of ethyl levulinate in combination with one of butylene glycol, TPM, and DPG results in non-ideal mixtures, which is unexpected. Additionally, as demonstrated with diffusion studies performed with PET wicks, the viscosity reduction of these non-ideal ethyl levulinate blends leads to faster diffusion ratesof the blends through the wick, which can provide a constant rate of fragrance delivery to the top of the wick for evaporation proximate to a diffuser. In cases in which a heated diffuser, a piezoelectric spraying system, an electrospray device, or a Venturi device is implemented, this constant fragrance delivery can achieve a constant fragrance evaporation rate.

[0093] FIGs. 3A through 5B present the variation of the viscosity as a function of the weight fraction (Xi) of lighter solvents (e.g., commercial solvents) in blends with butylene glycol, TPM and DPG, as well the viscosity deviation from an ideal binary mixture. As shown in FIGs. 3A through 5B, ethyl levulinate was determined to unexpectedly reduce the viscosity of the blends to a greater extent than when compared to blends of other commercial solvents (DPMA, DPM, DBE™ LVP and IPG). Thus, the results demonstrate that the binary mixtures of glycol-based solvents with ethyl levulinate form non-ideal mixtures.

[0094] The viscosity reduction of the binary solvent blends with ethyl levulinate was determined to have a direct impact on the diffusion velocity of the solvent blend in the wick, which is presented in graphical form in FIGs. 6 to 8. In each of the ethyl levulinate binary solvent mixtures (i.e., ethyl levulinate solvent blends with each of butylene glycol, TPM and DPG), ethyl levulinate promoted a diffusion velocity increase to a greater extent than other commercial solvents when the concentration of ethyl levulinate is in a weight ratio of 25:75 or greater in the solvent blend.

[0095] Embodiments of the present disclosure may provide at least one of the following advantages. The presence of ethyl levulinate in a fragrance carrier composition may reduce the viscosity of glycols and glycol ethers and provide non-ideal behavior in a binary mixture. When these low viscosity mixtures are used as a fragrance carrier composition in a fragrance delivery system, it is possible to obtain a faster diffusion in the porous wick as compared to commercial solvents and glycol-based solvents alone. Thus, this decrease in viscosity can maintain a constant delivery of the fragrance for consistent diffusion of the fragrance to the atmosphere.

[0096] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

CLAIMSWhat is claimed:

1. A fragrance carrier composition comprising: a levulinic acid-based solvent; and a glycol-based solvent, where the fragrance carrier composition is a non-ideal mixture.

2. The fragrance carrier composition of claim 1, wherein the levulinic acid-based solvent has Formula (II):Formula (II) wherein R is a Ci-Cio hydrocarbon group, preferably a Ci-Ce hydrocarbon group.

3. The fragrance carrier composition of claim 2, wherein R is a Ci-Cio alkyl or alkenyl group, preferably a Ci-Ce alkyl or alkenyl group.

4. The fragrance carrier composition of claim 2, wherein R is a C2-C6 hydrocarbon group, preferably a C2-C6 alkyl or alkenyl group, more preferably a C2-C3 hydrocarbon group, including an ethyl group, butyl group, and mixtures thereof.

5. The fragrance carrier composition of claim 1, wherein the levulinic acid-based solvent comprises an ester of levulinic acid.

6. The fragrance carrier composition of claim 2, wherein the levulinic acid-based solvent comprises at least 90 wt. %, preferably at least 95 wt. %, more preferably at least 98 wt. % of Formula (II).

7. The fragrance carrier composition of claim 1, wherein the levulinic acid-based solvent has Formula (III):Formula (III).

8. The fragrance carrier composition of claim 7, wherein the levulinic acid-based solvent comprises at least 90 wt. %, preferably at least 95 wt. %, more preferably at least 98 wt. % of Formula (II).

9. The fragrance carrier composition of any of the above claims, wherein the levulinic acidbased solvent has a vapor pressure of 0.20 mmHg (millimeters of mercury) or less at 20 °C.

10. The fragrance carrier composition of any of the above claims, wherein the levulinic acidbased solvent has a vapor pressure of 0.09 mmHg or less at 20 °C.

11. The fragrance carrier composition of any of the above claims, wherein the levulinic acidbased solvent reduces a viscosity of the glycol -based solvent.

12. The fragrance carrier composition of any of the above claims, wherein the glycol-based solvent is selected from the group consisting of a glycol, a glycol ether, and combinations thereof.

13. The fragrance carrier composition of claim 12, wherein the glycol-based solvent is selected from the group consisting of propyleneglycol, 1,2-pentanediol, 1,4-pentanediol, butylene glycol, tripropylene glycol methyl ether, dipropylene glycol, and combinations thereof.

14. The fragrance carrier composition of any of the above claims, wherein a ratio of levulinic acid-based solvent to the glycol-based solvent is in a range from 10:90 to 100:0 weight percent based on the total weight of the fragrance carrier composition (w / w).

15. A fragrance delivery system comprising: a fragrance delivery device comprising:a reservoir; a porous medium; and a diffuser, wherein at least a portion of a first end of the porous medium is disposed in the reservoir and an opposite end of the porous medium is located proximate to a diffuser, and wherein the reservoir includes a fragrance and the fragrance carrier composition of any of the above claims.

16. The fragrance delivery system of claim 15, wherein the porous medium is a wick, a reed diffuser stick, or combinations thereof.

17. The fragrance delivery system of claim 15 or 16, wherein the diffuser comprises a heater, a piezoelectric spraying system, an electrospray system, an aerosol diffuser, a reed diffuser stick, or combinations thereof.

18. The fragrance delivery system of any of claims 15 to 17, wherein the fragrance delivery system is one or more selected from a heated wick delivery system, a piezoelectric spraying system, an electrospray system, a Venturi device, or a wicking device.

19. A method for diffusing a fragrance into the air, the method comprising: diffusing a fragrance from a fragrance solution comprising a fragrance and the fragrance carrier composition of any of claims 1 to 14 into the atmosphere surrounding the fragrance delivery system.

20. The method of claim 19, further comprising passing the fragrance solution from a first end of a porous medium disposed in a reservoir of a fragrance delivery system through a porous medium to a second end of the porous medium.

21. The method of claim 20, wherein the fragrance solution passes from the first end of the porous medium to the second end of the porous medium at a constant rate.

22. The method of claim 20 or 21, wherein the levulinic acid-based solvent increases a rate of diffusion of the fragrance carrier composition through the porous medium as compared to a rate of diffusion of the glycol-based solvent through the porous medium.

23. Use of a levulinic acid-based solvent as a fragrance carrier in air care applications.

24. Use of the fragrance carrier composition of any of claims 1 to 14 as a fragrance carrier in air care applications.

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