DESC:FIELD OF THE INVENTION
The present invention relates to a microplastic-free biodegradable shelf-stable microcapsule powder formulation comprising a lipophilic active core such as a fragrance-core containing biodegradable shell, and preparation thereof, for incorporating in rinse off and leave on products.

BACKGROUND OF THE INVENTION
Fragrance plays a pivotal role in consumer preferences across various fast-moving consumer goods, significantly influencing purchase intent. The olfactory experience associated with a product category profoundly impacts consumer decisions. While the likability and intensity of fragrance are crucial factors in personal care products such as creams and lotions, they hold differing significance in products such as personal wash bars and laundry detergents – powder as well as liquid detergents. In personal care products such as wash bars, consumers evaluate fragrance at various stages, including point of purchase, during use, and post-bath, to assess its appeal. Conversely, in laundry products, fragrance evaluation extends from purchase to the washing process, including dissolution, soaking, rinsing, and fabric scent post-wash. Despite the importance of fragrance in rinse off or leave on products such as laundry products, achieving a long-lasting olfactory experience after rinsing has remained a challenge.

Existing methods primarily rely on free fragrance micellization facilitated by surfactants, resulting in minimal fragrance retention post-wash. Encapsulation of fragrances within hard-shell polymeric capsules presents a promising solution, enhancing fragrance longevity during rinse off applications. However, existing technologies lack comprehensive approaches for incorporating encapsulated fragrances into rinse off or leave on products such as laundry products, effectively.

US 4,145,184 discloses granular and liquid laundry detergent compositions comprising fragranced microcapsules.

US 6,248,703 discloses soap bar and detergent bar compositions comprising melamine capsules that contain essential oils.

WO 2007096790A1 discloses a process for the preparation of powdered aminoplast containing fragrances or other hydrophobic materials, using de-tackifying colloids such as modified starch, capsule, etc., with emulsifying properties and spray-drying of the capsule containing slurries. It also discloses consumer products such as water-free liquid detergent or fabric softener, hair or body oil or gel, hair or body spray based on cyclomethicone, and powder detergent or a fabric conditioning sheet.

WO 2004/016234 discloses spray-drying of aminoplast microcapsules in the presence of carboxymethylcellulose. However, inventors of the invention also disclosed that spray-dried powders were sticky and difficult to wash off from the spray-drier.

US 6,620,777 discloses improved deposition of fragranced aminoplast microcapsules on fabric from liquid fabric softeners with the inclusion of cationic polymers. However, none of the existing prior art discloses use of cationic polymer coated biodegradable capsules in powder form for improved delivery of fragrances onto fabric surfaces in the rinse off products.

US 5,137,646 discloses a process for the preparation and method of delivery of fragranced aminoplast particles which are stable in liquid compositions such as fabric softeners. However, this two-step manufacturing process involves the solidification of fragrances with a meltable polymer, followed by grinding of the solidified fragrances, and coating with the aminoplast resin.

IN 201921007894 discloses a free-flowing stable powdered aminoplast slurry premix with improved loading of fragrance that is stable at ambient conditions for 6 months to 1 year, and particularly provides a select process towards development of the same also optionally including cationic polymer for better deposition of said capsules on fabric. However, this microcapsule system is non-biodegradable.
WO 2024/023598 A1 discloses lipophilic active-core and polymeric shell material based microcapsules with improved thermal stability, wherein the particle size of said microcapsule ranges from 8 to 35 microns of Dv (90) value.

It is well known in the art that polymeric capsules are stable when present as aqueous slurries and, exhibit instabilities when dried to convert them to their powder form. This is because transportation and random movements during long-term storage ensure collision amongst various particles, due to which there are extensive capsule leakages. Although preparation of powdered aminoplast slurries have been reported in the art, none of the existing technologies are related to powdered capsules that can be applied in laundry rinse off and leave on products both in the solid form such as detergent powders as well as in aqueous dispersion form such as fabric conditioners. Furthermore, cationic modification of the powdered fragrance-containing capsules for effective adhesion on fabrics is not reported in art.

While various patents disclose the preparation and application of fragrance-containing microcapsules in liquid detergents and fabric softeners, solid forms or their incorporation into solid products are scarcely addressed. Furthermore, the challenges of producing powder capsules from aqueous slurries and achieving stable formulations comprising the same that are suitable for applications such as laundry applications, remain unaddressed.
Cationic modification of fragrance-containing microcapsules for improved adhesion onto fabric surfaces during or post- rinse off processes is an area of interest yet to be explored extensively. The prior art lacks methodologies for developing formulations comprising fully biodegradable microcapsules with a lipophilic active core such as fragrance as the core and a polymeric shell in stable, free-flowing powder form while also possessing long-term storage capability, in applications such as the rinse off and leave on laundry applications.

Hence, there is a strong need for a simplified method to produce mechanically stable and free-flowing powdered non-weeping biodegradable microcapsule formulation for use with rinse off products as well as leave on products. Modification of powdered microcapsules using cationic agents is desirable to enhance their deposition and adhesion onto fabrics during and post- rinse off cleansing, thereby addressing the existing limitations in the field of fragrance delivery in laundry products.

OBJECTS OF THE INVENTION
The principal object of the present invention is to provide a microplastic-free shelf-stable formulation comprising biodegradable microcapsules containing actives such as, but not limited to, fragrance as core, for use in rinse off and leave on products.

Another object of the invention is to provide a simple free-flowable microcapsule powder formulation comprising an active such as, but not limited to a fragrance core and a biodegradable polymeric shell, for use in rinse off and leave on products.

Yet another object of the invention is to provide enhanced loading of an active such as, but not limited to fragrance in rinse off and leave on products.

Still yet another object of the invention is to provide free-flowing, non-weeping, and non-caking powder formulation with lower dosage yet enhanced active such as, but not limited to fragrance loading for use in rinse off and leave on products.

Further object of the invention is to provide effective deposition and delivery of active such as, but not limited to fragrance containing microcapsules onto a substrate such as fabrics when incorporated in the products.

Further yet another object of the invention is to provide an active such as, but not limited to fragrance containing free-flowing microcapsules based formulation with good storage stability.

SUMMARY OF THE INVENTION
The present invention provides a microplastic-free, shelf-stable, free-flowable, non-weeping, and non-caking biodegradable microcapsules powder formulation, and a process of preparing said formulation. The formulation of the present invention comprises of actives such as but not limited to fragrance-containing biodegradable microcapsules, and a coating. Actives of said coating include biopolymer(s), naturally-occurring small molecules such as sugars, polyols, amino acids, additives, and optionally cationic polymers. Said biopolymer, naturally-occurring small molecules, and additives render storage stability, free-flowability, and improved loading of active such as but not limited to fragrance, while said cationic polymer further enhances deposition of said microcapsules on a substrate such as a fabric. The process of preparing said formulation comprises preparation of a microcapsule based slurry, and addition of coating for said microcapsules based slurry with the actives, followed by spray drying said formulation.

BRIEF DESCRIPTION OF THE DRAWINGS
The summary of the present invention, as well as the detailed description, are better understood when read in conjunction with the accompanying drawings that illustrate one or more possible embodiments of the present invention, wherein,
Figure 1 shows the average pre-rub and post-rub strengths of freshly prepared biodegradable microcapsule powder formulations (SD 01 – SD 05) of the present invention incorporated in detergent powder, and applied to a fabric;
Figure 2 shows the average pre-rub and post-rub strengths of biodegradable microcapsule powder formulations (SD 03 and SD 04) of the present invention incorporated in detergent powder, after 12 weeks at 45 °C with 70% relative humidity, and applied to a fabric;
Figure 3 shows the average pre-rub and post-rub strengths of freshly prepared biodegradable microcapsule powder formulations (SD 01 – SD 04) of the present invention incorporated in fabric softener and applied to a fabric; and
Figure 4 shows the Thermogravimetric Analysis of Spray dried biodegradable microcapsule powder formulations (SD 04 and SD 05) of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The summary of the present invention, as well as the detailed description, are better understood when read in conjunction with the accompanying drawings that illustrate the outcomes of one or more possible embodiments of the present invention.

The terms “lipophilic active core” and “lipophilic core” have herein been used interchangeably, and refer to a core comprising a lipophilic active material.

The terms “lipophilic core material” and “active” have herein been used interchangeably, and refer to the material forming the core wherein the material is a lipophilic active material.

The combination of one or more biopolymers, one or more naturally-occurring small molecules, one or more additives, and optionally one or more cationic polymers is herein referred to as “coating” or “coatings”.

As stated hereinbefore, the present invention provides a free-flowing microplastic-free biodegradable powder formulation comprising microcapsules comprising an active core such as but not limited to a fragrance core and a polymeric shell, for incorporation in rinse off and leave on products, and said microcapsule based slurry is coated with actives.

According to an embodiment, the microcapsule is characterized in that the lipophilic core material of said microcapsules comprises at least 95 percent by weight, preferably 100 percent by weight, based on the total weight of said lipophilic core material, and said lipophilic core material is selected from fragrances, profragrances, emollient oils, essential oils, hair-benefitting agents, skin-benefitting agents, conditioner actives, cosmetic care actives, personal care actives, UV absorbers, vitamins, anti-oxidants, anti-microbial agents, anti-viral agents, flavors, anti-malodor agents, pharmaceutical agents, dyes, printing inks, pesticides, biocides, agrochemicals, coating materials, anti-ageing actives, or the like, or combinations thereof.

According to an embodiment of the present invention, the free-flowing biodegradable microcapsule powder formulation of the present invention comprises a coating comprising a combination of biopolymers, naturally-occurring small molecules, additives, and optionally cationic polymer. Said combination renders attributes such as free-flowability, high storage stability, and enhanced loading of fragrance. The use of said cationic polymer in the formulation further enhances deposition of the core material such as but not limited to fragrance on fabric.

According to the embodiments of the present invention, said biopolymers are hydrolyzed biopolymers or modified biopolymers selected from but not limited to modified celluloses, polysaccharides, starches, gums, and plant-derived proteins. Examples of celluloses include, but are not limited to, hydroxyethyl cellulose, hydroxypropyl methylcellulose, carboxymethylcellulose, carboxymethyl hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, and methyl ethyl hydroxyethyl cellulose. Examples of commercially available hydroxypropyl methylcellulose include, but are not limited to, a free-flowing granular powder under the tradenames NATROSOL® (Ashland, Covington, Ky.), CELLOSIZE® (Dow, Midland, Mich.), and TYLOSE® (ShinEtsu, Tokyo, Japan).

Examples of starches include, but are not limited to, corn starch, potato starch, sweet potato starch, wheat starch, sago palm starch, tapioca starch, rice starch, soybean starch, arrow root starch, amylopectin starch, bracken starch, lotus starch, waxy maize starch, and high amylose corn starch. Examples of such starches include, but are not limited to, hydrolyzed low-molecular-weight and modified starches such as tapioca dextrins that possess film forming ability such as Crystal TexTM 626 and Crystal TexTM 644 sold by Ingredion, hydrogen octenyl butanedioate modified waxy maize starch such as Hi-CapTM 100 sold by Ingredion, carboxymethylcellulose, partially hydrolyzed natural waxy maize starch such as N-ZorbitTM 2144 DG sold by Ingredion, partially hydrolyzed maize starch, specialty maize starch such as AmazeTM by Ingredion, aluminum starch octenylsuccinate (Dry FloTM Plus sold by Ingredion), and maltodextrin.

Examples of gums include, but are not limited to, Arabicgum, tragacanth gum, guar gum, locust bean gum, carrageenans, alginate, gellan, xanthan gum, and pullulan.

Examples of plant-based proteins include, but are not limited to, isolates, concentrated, or hydrolyzed proteins such as but not limited to legumes (kidney bean, lima bean, adzuki bean, mung bean, golden gram, black gram, urad gram, scarlet runner bean, ricebean, moth bean, tepary bean, etc.), broad beans, peas, chickpeas, cow peas, pulses, pumpkin seeds, oat seeds, soy proteins, hemp seeds, edamame, and quinoa.

According to one or more embodiments of the present invention, one or more biopolymers and combinations thereof are selected from the above-mentioned examples of biopolymers.

According to the embodiments of the present invention, said naturally-occurring small molecules include, but are not limited to, isolated, purified, and modified small molecules originated from plants, but not limited to saccharides (monosaccharides, disaccharides, trisaccharides), low molecular weight dextrins (linear and cyclodextrins) obtained from hydrolysis of natural starch, polyols, amino acids, polyphenols, hydroxyl acids, fatty acids, lipids, and phytosterols.
Examples of saccharides include the commonly known small molecules such as but not limited to glucose, fructose, galactose, xylose, ribose, allulose, tagatose, and arabinose.

Examples of polyols include, but not limited to xylitol, maltitol, erythritol, sorbitol, threitol, arabitol, mannitol, and galactitol, lactitol, and galactitol.

Examples of naturally occurring amino acids include, but are not limited to, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

Examples of polyphenols include, but are not limited to, epigallocatechin gallate (EGCG), rutin, hesperidin, kaempferol, gallic acid, ellagic acid, tannic acid, chlorogenic acid, coumaric acid, pterostilbene, enterolactone, and procyanidin B2.

Examples of small organic hydroxyl acids include, but are not limited to, citric acid, lactic acid, malic acid, tartaric acid, mandelic acid, and glycolic acid.

Examples of naturally occurring plant-based fatty acids include, but are not limited to, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and -linolenic acid.
Examples of lipids include, but are not limited to, derivatives of fatty acids, such as triacylglycerides (TAGs) and glycerophospholipids (GPLs), a variety of aromatic and hydrocarbon-like compounds, such as sterols, carotenoids, terpenes, and waxes.

Examples of phytosterols include, but are not limited to, cholesterol, brassicasterol, campesterol, stigmasterol, ß -sitosterol, and avenasterol.

Additives employed in the present invention include, but are not limited to, silica, alumina, titania, zeolite, clays, wollastonite, salts such as sodium chloride, sodium sulfate, potassium chloride, potassium sulphate, potassium iodide, ammonium chloride, calcium carbonate, magnesium hydroxide, magnesium chloride, talc powder, or the like. Examples of natural clays include, but are not limited to, bentonite, montmorillonite, illite, calamine, and kaolinite.

Examples of cationic polymers used in the present invention include, but are not limited to, cationic polymers derived from modified natural polymers such as cellulose, starch, guar, cassia, tapioca, tara gum, and the like. Examples of commercially available naturally derived cationic polymers include polyquaternium-10, Guar gum, 2-hydroxy-3-(trimethylammonio) propyl ether chloride (JaguarTM C17 sold by Solvay), hydrolyzed cationic corn starch (CaTOTM 75Q sold by Ingredion), cationic hydrolyzed tapioca starch (SPACTM sold by SPAC starch products), crosslinked cationic tapioca starch (MICROCATTM 310 sold by Ingredion), and cationic hybrid corn starch (OptiPROTM 650 sold by Ingredion).

In accordance with the embodiments of the present invention, at least one biopolymer, one naturally-occurring small molecule, one additive, and optionally one cationic polymer, are in synergistic combination with biodegradable core-shell microcapsule slurry, to render a microplastic-free, shelf-stable, free-flowable, non-weeping, and non-caking biodegradable microcapsule powder formulation.

Said microcapsules comprise a core and a shell, wherein said shell may be made of polymers selected from biodegradable polyester such as, but not limited to, cross-linked polymethacrylate-co-vinyl acetate, and said core may be made of a lipophilic active such as, but not limited to, a fragrance.

It is to understood that for better understanding and the purpose of the study, the present invention is herein described considering fragrance as the core material, and that the scope of the invention is not limited to fragrance active as the lipophilic core material.
Polymeric microcapsules employed for experimentation purpose in the present invention include biodegradable shell-fragrance core microcapsules produced in-house with high loading of fragrances of up to 45%. The core-shell aqueous microcapsules comprise 25-65 weight% of total solid. The microcapsules are semi-impermeable in nature, that is, in the dry state, a portion (up to 20 weight%) of the core (e.g., fragrance) is found to be released slowly from the microcapsules over time. Therefore, it is very crucial to stabilize the microcapsules in the dry state to prevent such release of fragrance.

According to an embodiment of the present invention, said formulation comprises a biodegradable microcapsule slurry, and a coating comprising synergistic combination of biopolymer(s), naturally-occurring small molecule(s), additive(s), and optionally cationic polymer, with said liquid biodegradable microcapsule slurry and coating being in a ratio of 1:0.06 to 1:0.35. Said ratio aids in obtaining a storage stable free-flowable biodegradable microcapsule powder formulation with enhanced loading of fragrance after spray drying. Said formulation of the present invention has storage stability at ambient conditions for at least 1 year.

According to an embodiment of the present invention, said formulation comprises a coating which is a synergistic combination of one or more biopolymer), one or more naturally-occurring small molecules, one or more additives, in defined ratios to render free flowability thereby alleviating any caking activity, wherein the coating comprises 56 weight% to 85 weight% of biopolymer, 4 weight% to 21 weight% of naturally-occurring small molecule, and 2 weight% to 18 weight% of additives, to render improved barrier property, lower moisture-content, desired particles size, free-flowing property, storage stability, and non-weeping powder characteristics.

According to an alternate embodiment of the present invention, said formulation comprises a coating which is a synergistic combination of one or more biopolymers, one or more naturally-occurring small molecules, one or more additives, and one or more cationic polymers, in defined ratios, wherein the coating comprises 50 weight% to 85 weight% of biopolymer, 2 weight% to 21 weight% of naturally-occurring small molecule, 1.3 weight% to 18 weight% of additives, and 2 weight% to 21 weight% of cationic polymers, to render improved barrier property, lower moisture-content, desired particle size, free-flowing property, storage stability, improved performance via enhanced deposition, non-weeping and non-caking powder characteristics.
In accordance with the embodiments of the present invention, said microcapsules comprise a biodegradable polyester hard shell and a liquid core, preferably a lipophilic core such as but not limited to a liquid fragrance core, and have the potential to be incorporated in rinse off products such as detergent powder without caking problems, or can be incorporated in rinse off or leave on liquid products wherein said microcapsules survive the washing and rinsing processes, while retaining their ability to be lodged on fabric surfaces after drying of the same.

According to some embodiments of the present invention, said biodegradable microcapsules are cationically modified by cationic polymer thereby rendering enhanced deposition efficiency of said microcapsules on the fabric when incorporated in fabric care formulations such as but not limited to detergent powders and fabric softeners. Said cationic polymer aids in good dispersion of said microcapsules in said formulations for deposition onto fabric during rinse off.

The effective transfer and lodging of polymeric microcapsules onto fabrics in a rinse off or leave on product has been accomplished using rational principles of formulation design.

According to an embodiment of the present invention, a powder formulation comprising the free-flowable, biodegradable fragrance containing microcapsules of the present invention, is incorporated in a rinse off product or leave on product for desired effects. The deposition of microcapsules of flowable powders or aqueous slurries in rinse off products or leave on products is impacted, primarily, by stability of the micron-sized capsules in these products, and, importantly the transfer efficiency of these microcapsules onto a substrate such as fabrics. Using rational design principles, in accordance with the embodiments of the present invention, said microcapsules are adequately well protected in a stable free-flowable powder formulation and rendered suitable for further use in rinse off products or leave on products. The integrity of said microcapsules in said formulation is retained such that they are delivered onto a substrate such as a fabric even when used with rinse off products such as detergent powders and laundry liquids, or leave on products.

According to another embodiment of the present invention, the microcapsule powder formulation is suitable but not limited to applications in home and personal care products, cosmetic products, textile products, printing and coating applications, pharmaceutical formulations, consumer goods, and agro-industrial products.

Non-limiting examples of home care products containing microcapsule powder formulation of the present invention include, but are not limited to, air care products, house cleaning products, dish washing products, and laundering or fabric care products. Examples of air care products include, but are not limited to, aqueous air freshener liquids, gels, sprays, upholstery refreshers and sprays, and liquids for metered dosing articles, tablets, pellets, cakes, and pastes; house cleaning products include, but are not limited to, multi-surface cleaners, carpet cleaners, and hard surface cleaners; dishwashing products include, but are not limited to, liquid dishwashing agents, and dishwashing tablets and cakes; laundering or fabric care products include, but are not limited to, liquid and solid laundering detergents, fabric conditioners, fabric refreshers, fabric stiffeners, stain removing articles, fabric refresher sprays, solid fabric softener and refresher products, and fabric refresher cones; personal care products include, but are not limited to, leave on and rinse off hair and skin care compositions such as but not limited to shampoo, conditioner, hair removal depilatory, hair styling gel, hair colorant, antiperspirants, deodorants, aqua mist, spray and roll-on products, body washes, shower gels, hand washes, soap, body lotion, face washes, face mask, face cream, face serum, and sunscreens; and cosmetic products include, but are not limited to, lip-gloss, foundation, foundation primers, and eyeshadow.

According to an embodiment of the present invention, said free-flowable biodegradable microcapsule powder formulation is prepared by a simple process comprising of:
(i) preparing a biodegradable aqueous microcapsule slurry comprising a lipophilic active core and a polymeric shell by an emulsion polymerization process; (ii) coating the aqueous microcapsule slurry obtained in step (i), with a preformed mixture comprising biopolymers, naturally-occurring small molecules, additives, and optionally cationic polymers; and (iii) spray drying the slurry obtained in step (ii), with an inlet air temperature of 135 °C to 175 °C and outlet air temperature of 55 °C to 75 °C, to obtain a final product with a fragrance loading in said polymeric microcapsules in the range of 45-76 weight%.

According to the embodiments of the present invention, said formulation is prepared under mild conditions during spray drying involving economized temperature parameters of incoming air temperature of about 135° C and outcoming temperature of about 55°C, with a yield in the range of at least 80% to 95% on large-scale batches.

The inventors of the present invention have found that a system which when combined with aqueous slurries serves as a good vehicle for protecting the integrity of the microcapsule during the wash process and ensuring effective transfer and deposition of microcapsules onto substrates such as fabric surfaces.

According to an embodiment of the present invention, said hard shell biodegradable microcapsules could be loaded to up to 76 weight% in a formulation, and yet retain stability.

According to an embodiment of the present invention, said formulation comprises one or more cationic polymers, preferably cationic starch that enables the surface charges of the polymeric microcapsules to be further modified for better adhesion of the microcapsules to a substrate such as a fabric.

In accordance with the embodiments of the present invention, the fragrance contained in the formulation is fully biodegradable considering a combined score of 100 weight% of ready biodegradability (OECD 301) and inherent biodegradability (OECD 302) for all the ingredients. This implies that the ingredients are either readily biodegradable (as per OECD 301 guideline) or inherently biodegradable (following OECD 302 protocol). The polymeric shell, biopolymers, naturally-occurring small molecules, and cationic polymer were found to be biodegradable as per OECD 301 and OECD 302. The additives employed in the present invention are inorganic in nature. The formulation of the present invention exhibits enhanced storage stability, thermal stability, deposition, and fragrance delivery performance. Said microcapsule slurry would not be classified as microplastics under ECHA Regulation (EC) No. 1907/2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as regards to crosslinked synthetic polymer microparticles.

The EU has issued legislation to regulate microplastics under Annex XVII of REACH. The provisions in the new law will be implemented in phases, starting October 17, 2023. On September 27, 2023, the European Union (EU) issued Commission Regulation (EU) 2023/2055 to regulate synthetic polymer microparticles (‘microplastics’) as substances on their own and in mixtures (the Regulation).

‘Microplastics’ are solid plastic particles composed of mixtures of polymers and functional additives that are intentionally added and used in a wide variety of products. These include, but are not limited to, cosmetics, detergents, glitter, granular infill materials used in artificial sports surfaces, medical devices, paints, and toys.

According to the definitions in the Regulation, synthetic polymer microparticles means solid polymers meeting both the following conditions:
i) are contained in particles and constitute at least 1% of those particles; or build a continuous surface coating on particles, and
ii) at least 1% of the particles in the point above meet either of the following requirements:
‘microplastic’ means a particle containing solid polymer, to which additives or other substances may have been added, and where = 1% w/w of particles have (i) all dimensions 1 nm = x = 5 mm, or (ii) a length of 3 nm =x = 15 mm and length to diameter ratio of > 3.

A crosslinked synthetic polymer in the above-mentioned criteria will not be designated as synthetic polymer microparticle if it is a degradable polymer in accordance with Appendix 15 ‘Rules on proving degradability’ in the Regulation.

The individual ingredients of the powdered microcapsule formulation of the present invention exhibited complete biodegradation following OECD 301 (Ready biodegradation) and OCED 302 (Inherent biodegradation) protocols. Therefore, the microcapsule powder formulation of the present invention is designated to be microplastic-free.

The formulation of the present invention exhibits higher loading of fragrance oil in the biodegradable polymeric powder formulation thereby enabling lower dosage of powder polymeric microcapsules in the wash off and rinse off laundry products as well as leave on products, compared to prior art.

The polymeric capsule powder formulation was is found to be freely flowable with no noticeable caking activity at ambient storage condition for more than 12 months. The synergistic combination of biopolymers, naturally-occurring small molecules, and additives helps in preventing caking, and inclusion of cationic polymers further enhances deposition of the microcapsules on to the substrate.

The microcapsules of the powder formulation of the present invention were subjected to two hours of mechanical shaking at 1385 rpm to simulate a transportation test. Then the same was analysed by Thermogravimetric analyzer (TGA). No change in the TGA profiles was noticed before and after the mechanical shaking, inferring the stability of the microcapsules in the powder form.

A sample of the microcapsule powder formulation was further subjected to twelve weeks stability test following a standard ICH protocol (45 °C and 70% RH). Then the same was analysed by TGA. No change in the TGA profiles was noticed before and after the stability test, indicating the mechanical robustness of said polymeric microcapsule powder.

The powdered microcapsule composition of the present invention was further stored in an air tight container and stored for a year. After a year, the physical properties of the sample were analysed, and performance of the formulation in a detergent base was evaluated. The formulation was free flowing, free of any caking, free of any aggregate formation, and the moisture-content increased negligibly. It was also observed that there was no significant change in the performance. This was corroborated with TGA analysis of the sample.

As exemplary cases for the study, laundry rinse off formulations were incorporated with the microcapsule powder formulation of the present invention. The formulation of the present invention was incorporated in rinse off products such as detergent powder and fabric conditioners that are used in fabric washing process thereby enabling the successful deposition of said fragrance containing polymeric microcapsules onto fabrics post-washing and drying through rinse off cycle.

The surface charge of the fragrance-loaded microcapsules of the present invention was positively modified in situ through the addition of appropriate quantities of cationic polymer such as but not limited to cationically modified starch or charged polyquats, in the slurry.

Deposition of the microcapsules onto the surface of the fabric at post-laundry rinse off condition, demonstrated the advantage of in situ surface modification observed in the present invention. The same was established by comparing a formulation not comprising a cationic polymer and a formulation comprising a cationic polymer (for example, cationically-modified starch) in the biodegradable microcapsules based powder formulation. The sample with surface-charge modification was rated higher by panelists during a post-rinse off study.

The present invention provides a formulation exhibiting high stability to polymeric microcapsules without any caking activity, and delivery of said microcapsules onto fabric surfaces even when rinse off products or leave on products have been employed for fabric cleaning and care.

The polymeric microcapsules based formulation of the present invention is in a powdery freely flowable form thus maintaining the integrity of the microcapsules over a period of time without any compromise in its efficacy. The formulation of the present invention exhibits high deposition efficiency in terms of transfer of fragrance containing microcapsules.

The present invention will be more readily understood from the following non-limiting exemplary illustrations of the formulation in accordance with the embodiments of the present invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed that should not be construed to limit the scope of the present invention.

The present invention discloses a biodegradable microcapsule powder formulation having a particle size (D50) in the range of 100-200um, moisture content below 2%, and recovery yield percentage in the range of 80-95%, and is found to be free of any caking, free-flowing, free of any aggregates, non-weeping, high performing, and shelf-stable upon storage at ambient condition for a year, when said formulation comprises a biodegradable microcapsule slurry, and a coating comprising a synergistic combination comprising of one or more biopolymers, one or more naturally-occurring small molecules, one or more additives, and optionally one or more cationic polymers, in a ratio of 1:0.06 to 1:0.35. Said coating in the spray dried aqueous slurry formulation comprises 50-85 weight% of biopolymer, 2-21 weight% of naturally occurring small molecules, 1.3-18% of additives, and optionally 2-21 weight% of cationic polymers.

The present invention highlights the importance of an optimal amount of biopolymer ratio in the synergistic combination of microcapsule slurry in the range of 50-85%. Studies related to the present invention showed that when the amount of the biopolymer was more than 85%, the particle size increased to above 200 um and exhibited caking during stability at ambient condition, and when the amount of the biopolymer was less than 50%, the recovery (that is, yield percentage) of fresh microcapsule powder samples dropped to below 80% along with low performance when used in a consumer base, that is, a detergent or a fabric softener, and exhibited a low particle size of less than 100um. The microcapsule powder formulation of the present invention exhibits a particle size ranging between 100-200um, and is found to be uniformly distributed in a detergent powder formulation. In instances where the particle size was less than 100um, it resulted in a non-homogeneous distribution in a detergent powder formulation.

The present invention highlights the importance of an optimal amount of naturally occurring small molecules in the range of 2-21% in the coating of the microcapsule slurry. Studies related to the present invention showed that when the amount of the naturally occurring small molecule is more than 21%, the particle size increased to over 200um and the moisture % significantly increased to more than 2%, thereby resulting in aggregation and caking, whereas a an amount of less than 2% of the naturally occurring small molecules showed that the recovery yield % dropped to below 80%.

The present invention highlights the importance of an optimal amount of the additives in the synergistic combination of the microcapsule slurry in the range of 1.3-18%. Studies related to the present invention showed that when the amount of the additive is more than 18%, the particle size decreased to less than 100um thereby resulting in dusting and low density of the samples, whereas use of additives in an amount less than 1.3%, the sample did not exhibit free flowing property and resulted in caking.

The present invention highlights the importance of an optimal amount of cationic polymers in the range of 2-21% in the synergistic microcapsule slurry. Studies related to the present invention showed that when the amount of the cationic polymer was above 21%, it did not exhibit significant post-rub benefit of the fragrance. Also, when the amount of cationic polymer was less than 2%, a drop in the performance was observed.

Studies related to the present invention also revealed that a ratio of 1:0.06 to 1:0.35 of liquid biodegradable microcapsule slurry and coating is ideal, as a ratio of less than 1:0.06 resulted in leaching of the core oil which is about 20% of the total weight of the core.

Example 1: Preparation of biodegradable aqueous microcapsule slurry
The microcapsules of the present invention were prepared in accordance with the process disclosed in WO2024023598A1.
The weight% of combined polymers in solid content of the slurry formulation varies from 20 to 65%, and the total fragrance loading ranges from 5 to 85% weight%.
Said process for the preparation of biodegradable aqueous microcapsule slurry comprises:
1) dissolving a total of 5.8g of polymerizable molecules such as methacrylic acid, 2-hydroxyethyl methacrylate, ethylene diol dimethacrylate, pentaerythritol tetraacrylate, vinyl acetate, or the like, or combinations thereof, which are used as the building blocks, and 0.8g of dilauroyl peroxide which is used as an initiator, in 32.3g of lipophilic core, i.e., oil phase containing ingredients presented in Table 1, and heating at 40-55 °C under nitrogen while stirring at 100-200 rpm for 15- 45 minutes to form prepolymer(s);
2) dissolving emulsifier sodium dodecyl sulfate in water phase to prepare 64.8g of 1.02 weight% emulsifier solution;
3) emulsifying the oil phase obtained in step 1 in the aqueous phase obtained in step 2 by stirring at 1200-1400 rpm for up to 12 minutes using a propeller type stirrer;
4) heating the emulsion obtained in step 3, under nitrogen at 40-60 °C for 15 to 45 minutes followed by heating at 65-85 °C for 4-6 hours at 100-400 rpm; and
5) quenching the unreacted monomers of step 4, at 65-85 °C by adding 5g (0.06 weight%) of an aqueous persulfate solution.
Table 1.
Compound CAS No. Weight%
Dihydromyrcenol 18479-58-8 25
Isononyl acetate 40379-24-6 20
Tetraahydro linalool 78-69-3 15
Nerolidol 7212-44-4 10
Hexyl acetate 142-92-7 10
Methyl hexyl ketone 111-13-7 5
Aldehyde C12 MNA 110-41-8 5
Lemonile 61792-11-8 3
Clonal 2437-25-4 3
Allyl amyl glycolate 67634-00-8 2
Manzanate 39255-32-8 1.5
Melonal 106-72-9 0.5

The fragrance- containing core was found to be fully biodegradable (23% inherent and 77% readily biodegradable).
The slurry was found to be readily biodegradable as per OCED 301B.
Example 2: Preparation of slurry compositions for spray drying
The biodegradable slurry prepared in Example 1 was added to a coating composition comprising an aqueous mixture of biopolymers, naturally-occurring small molecules, additives and optionally cationic polymers to prepare slurries. Table 2 presents the different slurry samples (SD 01- SD 13) prepared for the study considering the biopolymer maltodextrin, the naturally-occurring small molecule dextrose, silica as the additive, and the cationic polymer Optipro 650.
Table 2:
Sample # Slurry (as per Example 1) Biopolymer (maltodextrin) Naturally-occurring small molecule (dextrose) Additive (Silica) Cationic Polymer (Optipro 650)
SD 01 100g 6.5g 0g 0g 0g
SD 02 100g 5.8g 1.47g 0g 0g
SD 03 100g 6.2g 1.3g 0.3g 0g
SD 04 100g 5.6g 2g 0.5g 1.7g
SD 05 100g 3g 1g 0.3g 0.4g
SD 06 100g 2.6g 1.37g 1.1g 1.5g
SD 07 100g 8.3g 0.4g 0.5g 0.1g
SD 08 100g 6.6g 3.5g 0.7g 1.2g
SD 09 100g 7.2g 0.12g 1.1g 0.9g
SD 10 100g 6.7g 2.2g 0.1g 1.2g
SD 11 100g 7.2g 1.47g 3.5g 0.9g
SD 12 100g 8.1g 1.85g 1.2g 3.8g
SD 13 100g 7.8g 1.74g 1.6g 0.2g

Example 3: Spray drying of slurry compositions
The slurry compositions obtained in Example 2 (SD 01 to SD 13) were spray-dried using a Techno Search Spray Dryer Model SPD-P-111 portable spray dryer. The incoming air temperature of the chamber was 135 °C–145 °C and the outgoing air temperature was 55 °C–65 °C during the spray-drying operation. A two fluid co-current nozzle of diameter 1.00 mm with auto-deblocking was used to spray-dry the samples to obtain the desired free-flowing polymeric microcapsule powder formulations. Recovery yields (weight%) of the obtained powder formulations under these conditions are presented in Table 3.

Table 3.
Sample # Recovery Yield %

SD 01 70
SD 02 76
SD 03 85
SD 04 88
SD 05 57
SD 06 47
SD 07 63
SD 08 54
SD 09 71
SD 10 39
SD 11 54
SD 12 66
SD 13 78

Example 4: Analysis of Spray-dried biodegradable microcapsule powders
Moisture content and particle size of the spray-dried samples SD 01 -SD 13 obtained in Example 3, were analyzed using Cole Parmer Moisture balance and Mastersizer 3000 particle size analyzer, and presented in Table 4.

Table 4.
Sample # Moisture-Content (weight%) Powder PSA (D50), µm
SD 01 2.35 51.4
SD 02 1.8 34.5
SD 03 1.5 161
SD 04 2 164
SD 05 1.3 123
SD 06 1.9 100
SD 07 3.6 257
SD 08 2.8 288
SD 09 4.5 325
SD 10 4 346
SD 11 5.2 67
SD 12 2.8 98
SD13 3.1 96

Samples with a recovery yield of more than 80%, particle size in the range of 100-200um, and moisture content equal to or below 2%, have been considered for further performance and stability analysis.

Example 5: Performance Analysis of Spray-dried biodegradable microcapsules powder in a detergent powder
Spray-dried biodegradable microcapsules powder (SD 01-SD 13) at 0.4% dosage was added to a detergent powder. For a single load of washing in a standard machine, about 40g of washing powder was added and the fabrics pre- and post- rub evaluations after drying were carried out by a trained panel of evaluators. It was observed that the post-rub performance of the microcapsules of the fresh samples of SD 01, SD 02, SD 05, SD 06, SD 07, SD 08, SD 09, SD 10, SD 11, SD 12, and SD 13 was below the acceptable average rating, i.e., the performance was found to be below 2 indicating poor post-rub performance. So, stability study was carried out for samples SD 03 and SD 04 at 45 °C for 12 weeks wherein a desired rating was provided by the trained panel of evaluators after 12 weeks. The scale of rating is provided in Table 5.
Table 5.

Rating Scale
For Profile rating For Strength
1 Completely disliked 0 No odour
2 Disliked 1 Very weak
3 Somewhat disliked 2 Weak
4 Neither liked nor Disliked 3 Just right
5 Somewhat liked 4 Strong
6 Liked 5 Very strong
7 Extremely liked
The ratings of the performance of the biodegradable microcapsule powder formulation in a detergent powder for freshly prepared samples (SD 01 - SD 05) are provided in Figure 1, and the performance of the biodegradable microcapsule powder formulation stored at 45 °C and mixed in a detergent powder after 12 weeks, is presented in Figure 2.
Example 6: Performance Analysis of Spray-dried biodegradable microcapsules powder (SD 01 - SD 04) in fabric softener:
Spray-dried biodegradable microcapsules powder (SD 01 - SD 13) at 0.4% dosage were added to a liquid fabric softener base. For a single load of washing in a standard machine, about 30g of liquid fabric softener base was added, and pre- and post- rub evaluations of the fabrics after drying, were carried out by a trained panel of evaluators. It was observed that the post-rub performance in microcapsules SD 01, SD 02, SD 05, SD 06, SD 07, SD 08, SD 09, SD 10, SD 11, SD 12, and SD 13 was below the acceptable average rating for freshly prepared samples. The ratings of the freshly prepared samples SD 01- SD04 are presented in Figure 3.

Example 7: Thermogravimetric Analysis of Spray dried biodegradable microcapsules powder (SD 04 and SD 05):
The isothermal thermogravimetric analysis (TGA) was carried out for SD 04 and SD 05 samples. This method is a thermal analysis technique used to study the thermal stability and decomposition kinetics of materials. This method comprises heating the sample to a constant temperature, and the change in its mass is monitored continuously over time. This allows for the determination of decomposition temperatures, the amount of volatile components, and the kinetics of thermal degradation. In the spray-dried biodegradable microcapsules powder (SD 04 and SD 05), it is important to have the optimal amounts of the shell and coating materials of the present invention. If the ratio of the microcapsule slurry and the coating is below or above the ratio of 1:0.06 to 1:0.35, it is difficult to retain the core as well as the desired properties of the microcapsules.
The conditions considered for the Isothermal TGA study are:
a) Heat from 30 °C to 120 °C at 10 °C/min, b) Holding for 60 min at 120 °C, and c) Heat from 120 °C to 800 °C at 60°C/min
From the TGA graphs presented in Figure 4, it can be observed that there is a significant loss of mass from 0 min to 60 min in sample SD 05 compared to SD 04 which is nearly 5-6 % of the microcapsule powder which is equivalent to around 18-20 % of direct loss of core.

Example 8: Stability study of Spray-dried biodegradable microcapsulepowder
The stability study was conducted on the spray-dried samples (SD 01 - SD 04) to evaluate their moisture content, particle size, and flowability. The results of these evaluations after12 weeks at 45 °C and relative humidity of 70%, and after 1 year at ambient conditions, are presented in Table 6 and Table 7 respectively.

Table 6.
Sample # Moisture % 12-week stability
Powder PSA(D50) Flowability
SD 01 4.9 60 The sample is not freely flowable and forms lumps
SD 02 3.6 42 The sample is not freely flowable and forms lumps
SD 03 2.2 189 The sample is flowable and but forms lumps
SD 04 1.9 167 Sample is flowable and no lumps formed

Table 7.
Sample # 1 Year stability at ambient conditions
Moisture % Powder PSA Flowability
D50
SD 01 5.5 257 The sample is not freely flowable and forms lumps
SD 02 4.2 300 The sample is not freely flowable and forms lumps
SD 03 2.5 236 The sample is flowable and but forms lumps
SD 04 2.1 185 Sample is flowable and no lumps formed

It was observed that samples SD 01 and SD 02 exhibited high moisture content (5.5% and 4.2% respectively), and were not flowable along with significant lump formation as these samples contain only biopolymer and naturally-occurring small molecule and no additive or cationic polymer. Sample SD 03 exhibited a moderate moisture content of 2.5%, and while it is not flowable, it exhibited only slight lump formation as it does not contain the optimal amount of additive needed to render free flowing nature to powderSD 04 which also comprises an additive and cationic polymer, exhibited the least moisture content among the samples considered for the study, with a moisture content of 2.1%, and is flowable with no lump formation.

It was observed that as the moisture content decreased, the flowability of the sample improves, and lump formation reduced. Sample SD 04, with the least moisture content, demonstrated the best flowability and no visible lump formation, indicating a direct correlation between lower moisture content and better flow properties.

The free-flowable biodegradable fragrance containing microcapsule powder formulation of the present invention exhibits high storage stability, enhanced loading of fragrance, and enhanced deposition of said microcapsules on substrates such as fabrics. The present invention provides a fully biodegradable microplastic-free product for delivery of actives such as but not limited to fragrances.

In accordance with the various embodiments of the present invention, a free-flowable microplastic-free biodegradable stable microcapsule powder formulation for use in rinse off and leave on products is provided, wherein said formulation comprises a microcapsule comprising a lipophilic active-containing core and a biodegradable polymeric shell, and a coating. Said microcapsule composition and the coating are in a synergistic combination in a ratio of 1:0.06 to 1:0.35. Said coating comprises of a synergistic combination of biopolymers, naturally-occurring small molecules, additives, and optionally cationic polymers. Said actives include but are not limited to fragrances, profragrances, emollient oils, essential oils, hair-benefitting agents, skin-benefitting agents, conditioner actives, cosmetic care actives, personal care actives, UV absorbers, vitamins, anti-oxidants, anti-microbial agents, anti-viral, flavors, anti-malodor agents, pharmaceutical agents, dyes, printing inks, pesticides, biocides, agrochemicals, coating materials, anti-ageing actives, or the like, and combinations thereof. Said active-containing microcapsules are optionally cationically modified by a cationic polymer to provide enhanced adhesion to a substrate during cleansing and post-rinse off. Said free-flowable biodegradable microcapsule powder formulation is prepared by a simple process comprising of (i) preparing a biodegradable aqueous microcapsule slurry comprising a lipophilic active core and a polymeric shell by an emulsion polymerization process; (ii) coating the aqueous microcapsule slurry obtained in step (i), with a preformed mixture comprising biopolymers, naturally-occurring small molecules, additives, and optionally cationic polymers; and (iii) spray drying the slurry obtained in step (ii), with an inlet air temperature of 135 °C to 175 °C and outlet air temperature of 55 °C to 75 °C, to obtain a free-flowable biodegradable microcapsule powder with an improved fragrance loading in said polymeric microcapsules in the range of 45-76 weight%.

Said biodegradable microcapsule powder formulation can be incorporated in rinse off and leave on products such as home and personal care products, cosmetic products, textile products, printing and coating products, pharmaceutical formulations, consumer goods, and agro-industrial products.

It is to be understood, however, that the present invention would not be limited by any means to the techniques, and approaches that are not specifically described, and any change and modifications to the techniques and approaches can be made without departing from the spirit and scope described in the present invention.
,CLAIMS:I/We claim:
1. A free-flowable microplastic-free stable biodegradable microcapsule powder formulation for use in rinse off and leave on products comprising of:
a microcapsule comprising an active-containing core and a biodegradable polymeric shell; and
a coating,
wherein
said biodegradable polymeric shell is a biodegradable polyester shell;
said active-containing core is a lipophilic core; and
said coating comprises a synergistic combination of biopolymers, naturally-occurring small molecules, additives, and optionally cationic polymers; and

said microcapsule composition and said coating are in a ratio of 1:0.06 to 1:0.35.

2. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said lipophilic core material comprises 95-100 percent by weight of an active, based on total weight of the lipophilic core material.

3. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said active is selected from fragrances, profragrances, emollient oils, essential oils, hair-benefitting agents, skin-benefitting agents, conditioner actives, cosmetic care actives, personal care actives, UV absorbers, vitamins, anti-oxidants, anti-microbial agents, anti-viral agents, flavors, anti-malodor agents, pharmaceutical agents, dyes, printing inks, pesticides, biocides, agrochemicals, coating materials, anti-ageing actives, and combinations thereof.

4. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein the coating comprises:
a. 50% to 85% by weight of one or more biopolymers;
b. 2% to 21% by weight of one or more naturally-occurring small molecules;
c. 1.3% to 18% by weight of one or more additives; and
d. optionally, 2% to 21% by weight of one or more cationic polymers.

5. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said biopolymers are selected from modified celluloses selected from hydroxypropyl methylcellulose, and carboxymethylcellulose, polysaccharides, starches, gums, plant-derived proteins, or the like.

6. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said naturally-occurring small molecules are selected from isolated, purified, and modified small molecules originated from plants.

7. The biodegradable microcapsule powder formulation as claimed in claim 6, wherein said naturally-occurring small molecules are selected from saccharides, low molecular weight dextrins, polyols, amino acids, polyphenols, hydroxyl acids, fatty acids, lipids, phytosterols, or the like.

8. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said additives are selected from silica, alumina, titania, zeolites, clays, wollastonite, talc powder, and salts selected from NaCl, Na2SO4, KCl, K2SO4, and NH4Cl.

9. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said cationic polymer is selected from cationic polymers derived from modified natural polymers selected from cellulose, starch, guar, cassia, tapioca, Tara, or the like.

10. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said cationic polymer is selected from cationically modified starches, polyquaternium compounds, cationically modified guar gums, or the like.

11. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein the powder formulation has a particle size distribution (D50) in the range of 100 to 200 µm, a moisture content of less than or equal to 2%, and a recovery yield percentage of greater than or equal to 80.

12. A process for preparing the biodegradable microcapsule powder formulation as claimed in claim 1, comprising of:
(i) preparing a biodegradable aqueous microcapsule slurry comprising a lipophilic active core and a polymeric shell by an emulsion polymerization process;
(ii) coating the aqueous microcapsule slurry obtained in step (i), with a preformed mixture comprising biopolymers, naturally-occurring small molecules, additives, and optionally cationic polymers; and
(iii) spray drying the slurry obtained in step (ii), with an inlet air temperature of 135 °C to 175 °C and outlet air temperature of 55 °C to 75 °C, to obtain a free-flowable biodegradable microcapsule powder.

13. The process as claimed in claim 12, wherein the spray drying is conducted under mild temperature conditions to obtain encapsulation integrity, and a yield of 80-95%.

14. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said microcapsules are loaded with the active in the range of 45 – 76 wt.% in said rinse-off and leave on products.

15. The biodegradable microcapsule powder formulation as claimed in claim 1, wherein said rinse off and leave on products are selected from home and personal care products, cosmetic products, textile products, printing and coating products, pharmaceutical formulations, consumer goods, and agro-industrial products.