process

Abstract

1. A method for covalently attaching a modifying agent to a polymeric microcapsule wall, the wall comprising an entity capable of reacting with an acrylic moiety, comprising providing a linking compound on the wall to which the modifying agent subsequently attaches, the linking compound having the formula I JPEG2023511711000011.jpg31163In formula, n=1 to 30; R1, R2, and R3 are independently selected from the following moieties: R1 and R3 are 、 H and Me; and X is selected from O and NH; and R2 has a group selected from CH2, CH2CH(OH)CH2, and CH2.CH2, such that the modified microcapsules exhibit enhanced substantivity to substrates such as fabrics when used in laundry formulations.

Description

[Technical Field]

[0001] The present disclosure relates to microcapsules, and more particularly to microcapsules that can be stably dispersed in aqueous liquids. More particularly, it relates to surface modification of the capsules to make them more anchorable to a substrate. [Background technology]

[0002] Microcapsules, i.e., capsules typically having an average diameter of about 50 nm to several mm, have been known and used for some time as a means of protecting encapsulated agents until they are needed. The range of encapsulated substances is quite wide, including dyes, cells, pharmaceuticals, enzymes, pigments, flavors, and fragrances. One particular application is the use of microcapsules for fragrance delivery in laundry applications, with the goal of protecting the fragrance until it is released from the capsule at a desired point. A wide range of capsule wall materials are known, ranging from gelatin to acrylics, polyureas, and aminoplasts. Aminoplasts, such as melamine-formaldehyde resins, form excellent capsules, and the material has become particularly popular because of its relative low cost.

[0003] It is desirable to be able to distribute microcapsules on a substrate so that they remain dispersed there. It is also desirable to be able to provide dispersibility to microcapsules in aqueous liquids so that they remain dispersed or at least are easily redispersible. These are not natural properties of most microcapsules, which means that a modifier must be provided to the capsules. In this case, the modifier is a material that either has affinity for both the capsules and the substrate or imparts ready dispersibility to the capsules, ideally capable of performing both functions. In the case of providing fragrance on laundry items during washing, this means that the modifier must impart substantivity to the specific substrate, whether natural, such as wool or cotton, or synthetic, such as acrylic, polyamide, or polyester, or a mixture of these materials. Typical modifiers are nonionic polysaccharides such as mannan, glucan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan, and mixtures thereof.

[0004] The modifier allows the microcapsules to adhere continuously to the substrate. The problem with modifiers is that their connection to the capsule is an equilibrium with the modifier molecules attaching to and detaching from the capsule.

[0005] It has been proposed to make modifiers more firmly attached. One approach has been to add a modifier to the fragrance dispersion so that a capsule wall forms, and the entanglement of the modifier with the formed wall causes the modifier to be fixed in place. This has been successful in some cases, but not all. In addition, some modifiers may interact with some perfume components in such a way as to alter the perfume properties and therefore the desired hedonic effect.

[0006] Another proposal is to covalently link the modifier to the capsule wall. This has the advantage that the capsule can be formed and then subsequently modified. This relies on complementary reactive groups on both the wall and the modifier, which is often not the case. One proposed way to overcome this is to use a linking compound, i.e., a compound with functionality that targets both the capsule wall and the modifier. Examples of this technique can be found in International Publications WO2006 / 1172902, WO2010 / 1424012, and WO2018 / 149775. Summary of the Invention

[0007] It has now been found that effective and durable immobilization of microcapsules to a substrate is feasible by a new mechanism. Accordingly, a method is provided for covalently attaching a modifier to a polymeric microcapsule wall, the wall comprising an entity capable of reacting with an acrylic moiety, and comprising providing a linking compound on the wall to which the modifier subsequently attaches, the linking compound being Formula I [ka] During the ceremony, n=1 to 30; R1, R2, and R3 are independently selected from the following moieties: R1 and R3 are H and Me; and X is selected from O and NH; and R2 is selected from CH2, CH2CH(OH)CH2, and CH2.CH2; It has.

[0008] In addition, the present disclosure also provides microcapsules prepared by the method described above. In specific embodiments, n is 1-23, 1-20, 1-15, 1-10, and 1-5. In specific embodiments, the linking compound is a compound having an acrylate moiety (CH2=CH.COO-) at one end and a methacrylate entity (CH2=C(CH3).COO-) at the other end, i.e., one of R1 and R3 is H and the other is CH3.

[0009] In further specific embodiments, R1 and R3 are both H or both CH3, and X is O, with the other moieties being as described above. In further specific embodiments, the linking compound has Formula II or Formula III: [ka] It is a compound according to the following:

[0010] The compound represented by formula II is 3-(acryloyloxy)-2-hydroxypropyl methacrylate.

[0011] The polymer that makes up the capsule wall can be any polymer containing an entity capable of reacting with an acrylic moiety, i.e., a moiety containing a prop-2-enoyl group (CH2=CH-CO-). Entities that will react with the acrylic moiety are nucleophilic groups, such as primary and secondary amines, hydroxyl, thio and phosphine (H-PR2) hypophosphites HP(O)OH, and phosphonates of the type H-PO(OH)2 or H-PO(OR)2.

[0012] Specific examples of polymers incorporating amine groups are aminoplasts, such as urea-formaldehyde resins, and melamine-formaldehyde resins, and polyureas.

[0013] The modifying agent may be any suitable modifying agent capable of reacting with the linking compound to form a covalent bond and thereby becoming permanently linked to the capsule surface. Exemplary modifying agents include polysaccharides such as mannan, glucan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan, and mixtures thereof.

[0014] The process of the present invention was carried out by adding the linking compound to a slurry of capsules, followed by the modifier, the linker, and the initiator.

[0015] The degree of grafting of the modifier, i.e., the proportion of the added modifier that adheres to the capsules, may be determined by any suitable method, such as gel permeation chromatography or viscosity measurement. A typical sample preparation procedure for GPC to determine the degree of grafting is described in the examples.

[0016] The modified capsules should therefore be easily redispersible when necessary and have the desired enhanced substantivity on the substrate, depending on the nature of the modification, and should have much greater substantivity on the substrate in that a greater proportion of the capsules will adhere to the substrate, thereby providing a much enhanced olfactory experience.

[0017] The microcapsules described above may be incorporated into any treatment formulation applied to a substrate. This may be, for example, a laundry formulation such as a laundry detergent (powder or liquid) or a fabric conditioner or softener. Accordingly, the present disclosure also provides such treatment formulations. Additionally, it provides a method for enhancing the subsistence of microcapsules applied to a substrate as part of a treatment formulation, the microcapsules being prepared as described above.

[0018] The present disclosure will be further described with reference to the following examples, which describe particular embodiments and are not intended to be limiting. All proportions are by weight.

[0019] Example 1 Preparation of perfume-containing urea-melamine-formaldehyde capsule A with hydroxypropyl cellulose grafting The following materials and quantities were used for 100 g of slurry: [Table 1] 1. Varying copolymers of ethylene and maleic anhydride 2. Polymethylol-melamine precondensate 3. Hydroxypropyl cellulose M CS dispersion

[0020] Prior to capsule preparation, a 2.85% aqueous solution of hydrolyzed ZeMac™ E400 was prepared. Similarly, a hydroxypropyl cellulose dispersion was prepared by dispersing hydroxypropyl cellulose in a glycerin / water solution that had been stirred at room temperature for 1 day. The reactor temperature was set to 35°C, and then: water (10 g), Zemac™ E400 prepared as above, and urea were added. The pH was adjusted to 4.6±0.2 using NaOH solution while stirring, and the stirring speed was adjusted to obtain the desired capsule size (15-20 μm). The flavor was added, and stirring was continued at 35°C. A portion of the Luracoll™ SD (1.4 g) was added and the temperature increased to 88° C. This temperature was maintained for 30 minutes, at which point the remainder of the Luracoll™ SD (0.6 g) was added and the temperature maintained. While maintaining stirring and temperature, the 3-(acryloyloxy)-2-hydroxypropyl-methacrylate and HPC were added. This was followed by the addition of potassium peroxodisulfate and the temperature maintained. The remainder of the water and ethylene urea were added prior to cooling the reaction mixture. Capsule characterization: solids content 32%, expected 33%; 50 =18μm;5 / 21s -1Viscosity at 25°C = 3000 / 1500 mPa.s; grafted HPC ≈ 40%.

[0021] The degree of grafting was determined by the following method: One volume part (typically 10 ml) of the capsule slurry was diluted with two volumes of ethanol, and the mixture was placed in an ultrasonic bath for 30 minutes at 25°C. The liquid was evaporated, and the solid residue was suspended in pentane and sonicated again for 20 minutes. The solid was filtered off and rinsed twice more with pentane. The off-white solid was collected from the filter and dried in air. A calculated amount of this powder (40-50 mg) was added to 5.0 ml of DMF, which was prepared as an eluent for gel permeation chromatography (0.1 mol / L LiBr was dissolved in DMF, and the solution was filtered first through a 0.45 μm and then a 0.2 μm pore size filter). The suspension was stirred at 60°C for 16 hours, filtered through a 0.45 μm pore size syringe filter, and injected into a gel permeation chromatography system. There, separation was performed through three columns (Water Styragel 4, 5, and 6, all 7.8 × 300 mm) covering the entire total molecular weight range of 6 × 10 6 The separation was performed up to g / mol. The detection system consisted of a Heleos II Dawn 8+ multi-angle laser light scattering (MALLS) and a differential refractive index (dRI, Optilab T-Rex) detector (both from Wyatt Technologies), allowing the detection and quantification of residual (non-grafted) surface-modifying agents. Separation conditions were: 0.5 ml / min flow rate, 50 °C, DMF / 0.1 M LiBr as eluent. The recovery of free, ungrafted polymer can now be determined and subtracted from the total polymer grafts used to yield the amount of grafted polymer.

[0022] Example 2 Preparation of fragrance-containing urea-melamine-formaldehyde capsules B using polysaccharides other than HPC The exact same procedure as in Example 1 was repeated except that the HPC was replaced with 0.5 g of polysaccharide modified with ammonium functionality. Capsule slurry characterization: solids content 32.4%, predicted 33.5%; d 50 =7μm;5 / 21s -1 Viscosity at (25°C) = 4000 / 1900 mPa.s;

[0023] Example 3 Preparation of perfume-containing urea-melamine-formaldehyde capsule C with grafts of hydroxypropyl cellulose. In a closed reactor equipped with a mechanical stirrer, 26 g of hydrolyzed ZeMac™ E400 solution (2.9%) and 16 g of water were introduced at room temperature and stirred at 200 RPM for 3 minutes. The stirring was then stopped, and fragrance (33 g) was added to the reactor, followed by 0.2 g of Dynasylan™ AMEO (3-aminopropyltriethoxysilane). Stirring (700 rpm) and heating were then started, and upon reaching 35°C, the pH was adjusted to 6.0 using aqueous NaOH. When the pH was adjusted to 4.6 using aqueous formic acid, stirring was maintained at 35°C for 1 hour. Luracoll SD (1.2 g) and urea (0.8 g) were added to the stirred solution, and heating was increased to reach 90°C. 30 minutes after reaching 90°C, 0.7 g of Luracoll was added, and heating was continued for another 120 minutes. 0.1 g of 3-(acryloyloxy)-2-hydroxypropyl methacrylate and 0.55 g of HPC, followed by potassium peroxodisulfate (KPS, 1 g of a % aqueous solution) were added to the reactor in two portions over the next hour. After another hour, 4 g of ethylene urea (30%) in water was added, followed by approximately 16 g of water. The slurry was cooled to 25° C. over a period of 1-2 hours. Capsule Slurry Characterization: 50 =17μm;5 / 21s -1 Viscosity at (25°C) = 2800 / 1800 mPa.s; HPC grafting ≈ 60%.

[0024] Example 4 Preparation of perfume-containing polyurea capsule D with hydroxypropyl cellulose grafts. [Table 2]

[0025] Into a reactor equipped with a mechanical stirrer, at 25°C and under gentle stirring, water, Floset™ DP CAPS 371L, and Bayhydur™ XP2547 were introduced, whereupon the stirring speed was increased to 1300 rpm. The isocyanate Desmodur™ and fragrance were simultaneously added to the stirred mixture, and stirring was continued for 30 minutes. An aqueous solution of Lupasol™ G100 was added to the stirred mixture, and heating was initiated; the temperature was gradually increased from 25°C to 85°C over 3 hours, where it was maintained for another 2 hours. 3-(Acryloyloxy)-2-hydroxypropyl-methacrylate was then added, followed by HPC (hydroxypropyl cellulose), KPS, and AIBN solutions, at 30-minute intervals. The temperature and stirring were maintained for another hour, at which time ammonia was added. After a short stirring period, the mixture was cooled to 25°C. Characterization: Solids content 43.2%, predicted 42.1%, d 50 : 14.8 μm; HPC graft: 60-70%

[0026] Example 5 Preparation of perfume-containing resorcinol-melamine-formaldehyde capsule E with grafts of hydroxypropyl cellulose. [Table 3]

[0027] In a reactor equipped with a mechanical stirrer, water, resorcinol, Floset™ DP / CAPS 371L, and Luracoll™ SD were added and stirring was started at 400 rpm. Once the mixture was homogenized, the fragrance was added and the stirring speed was increased to 950 rpm. The pH was adjusted to 3.5-4.0 using formic acid. The temperature was gradually increased to 75°C and maintained there for 1 hour. The pH was readjusted with formic acid and stirring at 75°C was maintained for another hour. The 3-(acryloyloxy)-2-hydroxypropyl-methacrylate and HPC, followed by KPS, were added to the reactor over the next hour at 75° C. Stirring was continued for another hour at 75° C. The ethylene urea solution was added and stirring was continued for another hour at 75° C., at which point heating was stopped and the mixture was cooled to 25° C. Capsule characterization: 50 = 10.7 μm; solid content 31.7%, predicted 33.3%; HCP graft %: ~40%.

[0028] Example 6 Preparation of perfume-containing urea-melamine-formaldehyde capsules F without surface modification For comparison purposes, capsule F was synthesized according to the procedure described in Example 1, but omitting the grafting step; that is, neither HPC, 3-(acryoyloxy)-2-hydroxypropyl-methacrylate, nor KPS was added to the reaction. This is an example of a capsule without surface modification. Capsule characterization: solid content 30%, expected 31%; 50 =17μm;5 / 21s -1 Viscosity at (25°C) = 1200 / 700 mPa.s.

[0029] Example 7 Preparation of fragrance-containing urea-melamine-formaldehyde capsules G with surface modification by xyloglucan through interencapsulation For comparison purposes, capsule G was synthesized according to the procedure from Example 1, but omitting HPC, 3-(acryloyloxy)-2-hydroxypropyl-methacrylate, and KPS. The difference with capsule A was the addition of 0.3 g of xyloglucan along with the addition of Luracoll SD at 88° C. This is an example of a capsule in which the surface modification was achieved by interencapsulation of a modifying agent in the outer layer of the capsule surface. Capsule characterization: solids content 32%, expected 33%; 50 =17.5μm;5 / 21s -1 Viscosity at (25°C) = 2800 / 1100 mPa.s.

[0030] Example 8 Preparation of fragrance-containing urea-melamine-formaldehyde capsules H with surface modification by hydroxypropyl cellulose via interencapsulation For comparison purposes, capsule H was synthesized according to the procedure from Example 1, but omitting 3-(acryloyloxy)-2-hydroxypropyl-methacrylate and KPS. HPC was added (in the same amounts as in Example 1) along with Luracoll at 88° C. This is an example of a capsule in which the surface modification was achieved by interencapsulation of a modifying agent in the outer layer of the capsule surface. Capsule characterization: solids content 19%, expected 33%; 50 =17μm;5 / 21s -1 Viscosity at (25°C) = 3000 / 1500 mPa.s; grafted HPC ≈ 20%.

[0031] A low solids content measurement indicates that the capsules cannot withstand drying, i.e., the encapsulated fragrance leaks out of the capsules as they dry, either because they are mechanically damaged or because the shell is insufficiently impermeable to prevent fragrance evaporation. Either way, this represents an example of poor fragrance encapsulation, likely as a result of modifier molecules interfering with the encapsulation process.

[0032] Example 9 Demonstration of the necessity of the components required for the grafting of modifiers Example 1 was repeated omitting one or more molecules used in the grafting stage (identified by "-" for the absence of the molecule and "+" for the presence of the molecule). Thus, No. 1 in the table below represents a synthesis in which only HPC was added and the linker and radical initiator were omitted. Entries 5-7 in the table describe variations in the radical initiator and its impact on grafting. The graft percentage was determined by the method described in Example 1. [Table 4]

[0033] What can be seen is In Nos. 1-3, very little HPC is grafted (recovery is nearly complete), demonstrating that the absence of one of the modifiers (HPC), linker, or initiator leads to almost no grafting. In No. 4 (identical to Example 1), there was 50% grafting, a substantial result. In No. 5, the use of AIBN initiator (soluble in oil) gives slightly worse, but still acceptable, results than in No. 4. In No. 6, the combination of the two types of initiators showed no improvement over KPS used alone. In No. 7, the use of 2,2'-azobis-(2-methylpropionamidine)-dihydrochloride initiator gives results equivalent to those of No. 4.

[0034] Example 10 Demonstration of the olfactory benefits of grafting HPC onto a polyester substrate (T-shirt) Polyester is known to be a difficult substrate for fragrance deposition, especially for encapsulated fragrances, likely because the smooth, hard surface of polyester fibers provides a very small contact area for the fragrance capsules, requiring high adhesion energy to achieve high olfactory performance between the two objects. Liquid detergent samples containing Capsules A, C, F, G, and H, as prepared in Examples 1, 3, 6, 7, and 8, respectively, were prepared by dispersing the capsule slurries in identical amounts (50 g) of liquid detergent base. The fragrance concentration level was identical in all of the samples. Each was subjected to a wash cycle in a standard European-style washing machine (front-loading) with five cotton towels and three polyester T-shirts, plus additional cotton sheets to fill the washing machine load up to 5 kg. After drying, the substrate was lightly rubbed to break the capsules and release the fragrance, and the post-rub fragrance boost performance was evaluated by noting the perceived fragrance intensity. The fragrances were assessed by a panel of seven expert testers. Capsule G was taken as the standard (in which the modifier was encapsulated by an art-recognized method of encapsulation). The olfactory assessment was based on the following scale: 1 - No difference or less than standard capsules 2- Slightly stronger than standard capsules 3- Significantly stronger than standard capsules 4- Significantly stronger than standard capsules Based on. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 shows the results of Example 10.

[0036] The numbers were averaged and the results are shown in Figure 1. It can be seen that the performance of the samples (A and C) in which the modifier was covalently grafted was significantly higher than that of the other samples. Capsule I, with its low performance, proves that the interencapsulation route to surface modification is not the way to introduce this specific modifier. Even though capsule G can be prepared by coencapsulation, its performance is still lower than that of A and C, but higher than that of the unmodified capsule F.

[0037] Thus, this example highlights not only the benefits of surface modification of capsules for higher olfactory performance (F vs. A, C, and G), but also the advantages of covalent bonding over mutual encapsulation strategies, especially when the molecule of interest is not available via encapsulation methods. [Table 5]

Claims

1. 1. A method for covalently attaching a modifying agent to a polymeric microcapsule wall, the wall comprising an entity capable of reacting with an acrylic moiety, comprising providing a linking compound on the wall to which the modifying agent is subsequently attached, the linking compound having the formula I 【Chemistry 1】 During the ceremony, n = 1 to 30; R 1 , R 2 and R 3 are independently selected from the following moieties: R 1 and R 3 is H and Me; and X is selected from O and NH; and R 2 is CH 2 , C.H. 2 CH(OH)CH 2 , and C.H. 2 .CH 2 Selected from: The method comprising:

2. 2. The method of claim 1, wherein n is selected from 1-23.

3. The linking compound has an acrylate moiety (CH 2 =CH.COO-), and at the other end a methacrylate entity (CH 2 =C(CH 3 The method of claim 1, wherein the compound has the formula: .COO-.

4. R 1 and R 3 But both are H or both are CH 3 and X is O.

5. The linking compound has Formula II and Formula III: 【Chemistry 2】 The method according to claim 1, wherein the compound is selected from the group consisting of compounds represented by the formula:

6. The method of claim 5, wherein the linking compound is 3-(acryloyloxy)-2-hydroxypropyl methacrylate.

7. The method of claim 1 , wherein the polymeric microcapsule wall comprises amine groups.

8. 8. The method of claim 7, wherein the polymeric material of the microcapsule wall is selected from aminoplasts and polyureas.

9. 10. The method of claim 1, wherein the modifying agent is selected from at least one polysaccharide.

10. 10. The method of claim 9, wherein the polysaccharide is selected from mannan, glucan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan, and mixtures thereof.

11. 10. The method of claim 1, wherein the microcapsules contain a fragrance.

12. 10. Microcapsules prepared by the method of claim 1.

13. A treatment formulation, in particular a laundry formulation, comprising the microcapsules of claim 12.

14. 10. A method for enhancing the substantivity of microcapsules applied to a substrate as part of a treatment formulation, the microcapsules being prepared according to the method of claim 1.

15. 15. The method of claim 14, wherein the treatment formulation is a laundry product and the microcapsules contain a fragrance.

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