The following four patents describe different methods of providing longevity of perfume in personal care products
1. Compositions comprising an efficient perfume bloom
US Patent 10,449,131
Application No 15/866,724
Granted 22 October 2019
Assignee Procter & Gamble
The applicants maintain that consumers desire personal care products, such as shampoos and body washes, to have pleasant fragrances, and that products having intense perfume blooms or bursts are particularly appealing as they provide a more noticeable sensory impact.
However, personal care products frequently include many perfume materials that do not contribute to the overall perception of the fragrance at a noticeable level.
The patent describes a method of making body wash and shampoo compositions comprising about 3% to about 15% of anionic surfactant and adding about 0.05-0.4% of a perfume comprising at least ten perfume raw materials.
An odour intensity rating (OIR) is determined at two on a scale from zero to five and methods of detecting odour thresholds and intensities by sensory panels are described in detail.
The applicants have selected perfume materials capable of providing a high perceived odour intensity when present in a product at a low concentration; a list of suitable perfume raw materials and three possible combinations is given in the patent.
An extensive list of suitable surfactants and additives for making shampoos and body washes is shown and some illustrative formulations are included with various perfume additions and the results of sensory panel testing.
2. Perfume composition
US Patent 10,456,338
Application No 15/526,580
Granted 29 October 2019
The patent describes a perfume composition provided in the form of dispersed perfume-containing droplets, suspended in an aqueous medium.
The perfume droplets comprise more than 60% of perfume ingredients and 25% or less are linear or branched alkyl alcohols and/or alkenyl alcohols; 10% or less are aldehydes; and 10% or less have a partition coefficient (cLogP) of less than 2.1.
The perfume-containing droplets are coated with a layer of coacervate formed as the reaction product between a cationic polymer, preferably amodimethicone, and an anionic polymer, preferably a crosslinked acrylates/C10-30 alkyl acrylate copolymer.
The dispersing medium is a gel and a method of preparing a perfume composition is described comprising passing a mixture of the perfume composition and cationic polymer through a conduit opening into a second fluid comprising an aqueous continuous phase and an anionic polymer.
The coacervate layer is formed by the interaction of oppositely charged coacervate precursor polymers at the interface between internal and continuous phases, and each of the droplets is coated with a layer of coacervate, which essentially acts as a barrier separating the droplets of internal phase from the continuous phase, preventing coalescence of the droplets.
The perfume composition is free of polar solvents and surfactants, and is substantially free of water-miscible or partially miscible solvents, alcoholic solvents and glycols.
In addition to the perfume ingredients, the droplets may contain colourants, stabilisers, chelating agents, preservatives, emollients and modifiers for modifying texture, viscosity, pH, osmotic force or refractive index.
3. Fragrance compositions and uses thereof
US Patent 10,501,706
Application No 15/175,781
Granted 10 December 2019
Assignee Procter & Gamble
According to the applicants, perfumers select fragrance materials to blend into a composition with the goal of achieving an overall specific fragrance profile of strength and character.
In so doing, they need to bear in mind differences in the individual character and volatility of the fragrance materials that are the components of the full fragrance.
Conventional perfuming compositions have fragrance profiles characterised by a high amount of low volatile fragrance materials and lower amounts of volatile fragrance materials. Perfumers typically classify fragrance materials according to their specific characters.
The low volatile fragrance materials are known as ‘base notes’, while the volatile fragrance materials can be further divided into high volatile fragrance materials – identified as ‘top’ or ‘head notes’ – and medium or moderate volatile fragrance materials, identified as ‘middle’ or ‘heart notes’.
One problem with this classification approach is that due to the subjective nature of characters, there is inconsistency with the construction of fragrance compositions.
Another problem is that consumers often complain that middle notes tend to fade too quickly after application of the composition, and that the character of the middle notes are undesirably altered by the presence of large amounts of the base notes during the period known as the ‘dry down’ phase.
The applicants sought to provide new rules for objectively classifying fragrance materials according to their volatility using their vapour pressures defined at a suitable temperature.
Fragrance materials were thus classified into low volatile fragrance materials or volatile fragrance materials for formulating into fragrance mixtures that retain a significant portion of their initial fragrance profile over time.
Claimed is a fragranced composition wherein the fragrance component comprises at least one low volatile fragrance material having a vapour pressure less than 0.001 Torr at 25°C, at least one substantially non-odourous fragrance modulator and a second fragrance comprising one or more volatile fragrance materials having a vapour pressure greater than or equal to 0.001 Torr at 25°C.
Extensive lists of volatile and low volatile perfume materials are given. The non-odourous modulator is preferably one or more sucrose esters or trimethylcyclohexane derivatives.It is claimed that by reducing the levels of the low volatile fragrance materials, and preferably increasing the levels of the volatile fragrance materials in a composition, the effect of the substantially non-odourous modulator on the fragrance profile leads to prolonged longevity of the fragrance.
4. Process for preparing polyurea microcapsules with improved deposition
US Patent 10,508,253
Application No 15/318,614
Granted 17 December 2019
The patent claims a process for producing perfume or flavour-containing polyurea microcapsules with improved deposition of encapsulated actives on targeted surfaces, such as fibre, hair and skin.
The process for the preparation of core-shell microcapsules comprises dissolving at least one polyisocyanate in a perfume to form an oil phase; dispersing the oil phase into an aqueous solution of an emulsifier to form an oil-in-water emulsion; and sequentially adding polymeric crosslinker-bearing amino groups followed by a polyamine to form a microcapsule slurry.
The process generates aggregated droplets and provides capsules that are at least partly aggregated through intermolecular forces such as electrostatic interaction, hydrogen bonding and interfacial reactions.
The concentration of perfume is between 10% and 60% by weight relative to the total weight of the microcapsule slurry, and the microcapsules show an improved deposition of the active ingredient on target surfaces while showing good stability in application and good perfume or flavour retention.
Preferably the isocyanate is a mixture of a biuret of hexamethylene diisocyanate with a trimethylol propane-adduct of xylylene diisocyanate, and the emulsifier should be anionic.
Amphiphilic cationic polymers can also be used as emulsifiers or co-emulsifiers with non-ionic emulsifiers to form positively charged capsules.
Preferably the polyisocyanate is used in an amount between 2% and 20%. The polymeric crosslinker-bearing amino groups are preferably polyvinylamine or polyethyleimine, or mixtures thereof.
It is essential to the process that the polymeric crosslinker-bearing amino groups are added before the polyamine that is going to react with the polyisocyanate by interfacial polymerisation.
The amino groups of the polymeric crosslinker react with the isocyanate functional groups of two different droplets to form covalent bonds between drops, which leads to at least partial aggregation.