US-12624316-B2 - Treatment composition with delivery particles made from acid-treated chitosan

US12624316B2US 12624316 B2US12624316 B2US 12624316B2US-12624316-B2

Abstract

A treatment composition that includes a treatment adjunct and a population of core/shell delivery particles, where the shell is made from an acid-treated chitosan and a cross-linking agent, where the acid-treated chitosan results from treating chitosan with a weak acid, or even a mixture of a strong acid and a weak acid. Related methods of making and using such compositions.

Inventors

Conny Erna Alice Joos
MEAGAN MARIE KOCHEL
Johan Smets
Ariel Lebron
Jennifer Beth ALLISON
Mattia COLLU
Susana Fernandez Prieto
Olav Pieter Dora Tony Keijzer
Linsheng Feng
SONIA MARCELA MALAGON GOMEZ

Assignees

THE PROCTER & GAMBLE COMPANY

Dates

Publication Date: 20260512
Application Date: 20231129

Claims (14)

1 . A treatment composition comprising a treatment adjunct and a population of delivery particles, wherein the delivery particles comprise a core and shell surrounding the core, wherein the core comprises a benefit agent, wherein the benefit agent comprises a fragrance material, wherein the shell consists of a polymeric material that is a reaction product of an acid-treated chitosan and at least one cross-linking agent, wherein the acid-treated chitosan results from treating chitosan with a mixture of a first acid and a second acid, the first acid is a strong acid, the second acid is a weak acid, wherein the first acid and the second acid are present in a normality ratio of from about 35:65 to about 65:35, wherein the chitosan is treated with the mixture at a pH of 6.5 or less, and at a temperature of at least 25° C., wherein the at least one cross-linking agent is polyisocyanate, and wherein the treatment adjunct comprises a conditioning active.
2 . The treatment composition according to claim 1 , wherein the first acid is selected from the group consisting of hydrochloric acid, perchloric acid, nitric acid, sulfuric acid, and a mixture thereof.
3 . The treatment composition according to claim 1 , wherein the second acid is selected from the group consisting of formic acid, acetic acid, ascorbic acid, glutamic acid, lactic acid, maleic acid, malic acid, succinic acid, citric acid, acrylic acid, oxalic acid, tartaric acid, and a mixture thereof.
4 . The treatment composition according to claim 1 , wherein the first acid has a first pKa of less than 1, and the second acid has a first pKa of from about 1 to about 5.5.
5 . The treatment composition according to claim 1 , wherein the chitosan is characterized by a weight average molecular weight of from about 100 kDa to about 600 kDa.
6 . The treatment composition according to claim 1 , wherein the reaction product is formed in a reaction, wherein the weight ratio of the chitosan present in the reaction to the cross-linker present in the reaction is from about 1:10 to about 1:0.1.
7 . The treatment composition according to claim 1 , wherein the fragrance material comprises perfume raw materials characterized by a logP of from about 2.5 to about 4.5.
8 . The treatment composition according to claim 1 , wherein the core further comprises a partitioning modifier.
9 . The treatment composition according to claim 1 , wherein the delivery particles are characterized by a volume-weighted median particle size from about 1 to about 100 microns.
10 . The treatment composition according to claim 1 , wherein the delivery particles are obtainable from a process comprising the steps of: forming a water phase by treating the chitosan with the mixture of the first acid and the second acid, wherein the chitosan is treated at a pH of 6.5 or less, and at a temperature of at least 25° C., for at least one hour, thereby forming an acid-treated chitosan; forming an oil phase, the forming step comprising dissolving together the benefit agent and the at least one cross-linking agent; forming an emulsion by mixing the oil phase into an excess of the water phase, thereby forming droplets of the oil phase dispersed in the water phase, and optionally adjusting the pH of the emulsion to be in a range from pH 2 to pH 6; curing the emulsion at a temperature of at least 40° C. for a time sufficient to form a shell at an interface of the droplets with the water phase, the shell consisting of the reaction product of the at least one cross-linking agent and the acid-treated chitosan, and the shell surrounding the core comprising the droplets of the oil phase.
11 . The treatment composition according to claim 1 , wherein the delivery particles are cationic and characterized by a zeta potential of at least 15 mV at a pH of 4.5.
12 . The treatment composition according to claim 1 , wherein the shells of the delivery particles degrade at least 60% in 60 days when tested according to test method OECD 301B.
13 . The treatment composition according to claim 1 , wherein the treatment adjunct further cmprises surfactants, deposition aids, rheology modifiers or structurants, bleach systems, stabilizers, builders, chelating agents, dye transfer inhibiting agents, dispersants, enzymes, enzyme stabilizers, catalytic metal complexes, polymeric dispersing agents, clay and soil removal/anti-redeposition agents, brighteners, suds suppressors, silicones, hueing agents, aesthetic dyes, neat perfume, additional perfume delivery systems, structure elasticizing agents, carriers, hydrotropes, processing aids, anti-agglomeration agents, coatings, formaldehyde scavengers, pigments, or mixtures thereof.
14 . The treatment composition according to claim 1 , wherein the treatment adjunct further comprises anionic surfactant, a cationic conditioning agent, or a mixture thereof.

Description

FIELD OF THE INVENTION The present disclosure relates to a treatment composition that includes a treatment adjunct and a population of core/shell delivery particles, where the shell is made from an acid-treated chitosan and a cross-linking agent, where the acid-treated chitosan results from treating chitosan with a weak acid, or even with a mixture of a strong acid and a weak acid. The present disclosure also relates to related methods of making and using such compositions. BACKGROUND OF THE INVENTION Delivery particles, particularly core/shell delivery particles, are a convenient way to delivery benefit agents in treatment compositions such as laundry products. For environmental reasons, it may be desirable to use delivery particles that have a wall made from naturally-derived and/or biodegradeable materials. Delivery particles having a shell made at least in part from chitosan-based materials are known. However, such particles may not deliver the desired level of performance. Furthermore, chitosan can be a challenging material to work with due to its viscosity-building tendencies. U.S. Patent Publication 2021/0252469 discloses treatment of chitosan in an acidic medium prior to the formation of microcapsules, for example by adjusting the pH with hydrochloric acid (HCl). However, there are challenges associated with such treatment methods. For example, under certain conditions, hydrochloric acid can be corrosive to manufacturing equipment, which is typically made of steel. Additionally or alternatively, improvements in the performance of delivery particles are still desired. There is a need for improved treatment compositions that include delivery particles made from chitosan-based materials, as well as related methods. SUMMARY OF THE INVENTION The present disclosure relates to treatment compositions that include chitosan-based core/shell delivery particles, where the chitosan is treated by a weak acid, or even a mixture of a strong acid and a weak acid. For example, the present disclosure relates to a treatment composition that includes a treatment adjunct and a population of delivery particles, where the delivery particles include a core and shell surrounding the core, where the core includes a benefit agent, where the shell includes a polymeric material that is the reaction product of chitosan and a cross-linking agent, where the acid-treated chitosan results from treating chitosan with a mixture of a first acid and a second acid, the first acid comprising a strong acid, the second acid comprising a weak acid, where the first acid and the second acid are present in a normality ratio of from about 20:80 to about 80:20, preferably from about 35:65 to about 65:35, wherein the chitosan is treated with the mixture at a pH of 6.5 or less, and at a temperature of at least 25° C. The present disclosure also relates to a treatment composition that includes a treatment adjunct and a population of delivery particles, where the delivery particles include a core and shell surrounding the core, where the core includes a benefit agent, where the shell includes a polymeric material that is the reaction product of an acid-treated chitosan and a cross-linking agent, wherein the acid-treated chitosan results from treating chitosan with an acid, where the acid includes one or more weak acids, where the chitosan is treated with the acid at a pH of 6.5 or less, and at a temperature of at least 25° C.; and where the treatment adjunct includes a conditioning active. The present disclosure also relates to a method of making a treatment composition, where the method includes the steps of: providing a base composition, wherein the base composition comprises a treatment adjunct, and combining the population of delivery particles with the base composition. The present disclosure also relates to a method of treating a surface, where the method includes the step of: contacting a surface, preferably a fabric, with a treatment composition as described herein. DETAILED DESCRIPTION OF THE INVENTION The present disclosure relates to treatment compositions that include delivery particles having shells made, at least in part, from chitosan-based materials. In particular, the delivery particles include a shell comprising a reaction product of chitosan and a cross-linking agent. Prior to shell formation, the chitosan used to make the particle shells is treated with a weak acid, or even a mixture of acids, namely a mixture comprising a strong acid and a weak acid. Typically, when chitosan is dissolved in water, for example during the process of making delivery particles, the resulting mixture tends to be quite viscous. This can result in flowability and processing challenges, and/or inhibit the adequate formation of delivery particle shells. It has been found that the acid treatment can result in a decrease of the mixture's viscosity. Additionally, it is believed that acid treating the chitosan can beneficially affect the molecular weight of th