PROCESS.

Abstract

The present invention relates to a method for covalently linking a modifier to a polymeric microcapsule wall, wherein the wall comprises entities capable of reacting with acrylic moieties, comprising supplying a linking compound onto the wall to which the modifier subsequently links, the linking compound having Formula (I), wherein n = 1 to 30; R1, R2, and R3 are independently selected from the following moieties: R1 and R3 are H and Me; X is selected from O and NH; and R2 is selected from CH2, CH2CH(OH)CH2, and CH2.CH2. In this manner, the modified microcapsules exhibit improved substantivity to substrates, such as textiles, when used in laundry preparations.

Description

PROCESS pfrfrQnn / zznz / E / YiAi Description of the Invention This description relates to microcapsules, and more specifically to microcapsules that can be stably dispersed in aqueous liquids. More specifically, it relates to modifying the surface of capsules to make them more substantial to the substrates. Microcapsules, typically capsules with average diameters ranging from approximately 50 nm to several mm, have been known and used for some time as a means of protecting encapsulated actives until needed. The range of encapsulated substances has been very broad, including dyes, cells, pharmaceuticals, enzymes, pigments, flavorings, and fragrances. One particular application is the use of microcapsules for fragrance release in laundry applications, the objective being to protect the fragrance until the desired point, at which time it is released from the capsule. A wide range of materials are known for capsule walls, from gelatin to acrylics, polyureas, and aminoplasts. Aminoplasts, such as melamine-formaldehyde resin, have been particularly popular because they form excellent capsules and the material is relatively inexpensive. The goal is to be able to deposit microcapsules onto a substrate,Ref. 335437 so that they remain in place. It is also desirable to provide dispersibility to the microcapsules in aqueous liquids so that they remain dispersed, or at least redisperse easily. These are not natural properties of most microcapsules, and this means that it is necessary to provide a modifier to the capsules. In this case, a modifier is a material that either has an affinity for both the capsule and the substrate, or that confers easy dispersibility to the capsules, with the ideal material being capable of performing both functions. In the case of providing fragrance to garments during washing, this means that the modifier must provide substantivity to the particular substrate, whether natural, such as wool or cotton, or synthetic, such as acrylics, polyamides, or polyesters, or mixtures of these materials.Typical modifiers are non-ionic polysaccharides, such as mannan, glucan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan, and mixtures thereof. The modifier allows the microcapsules to bind sequentially to the substrate. The problem with modifiers is that the connection with the capsule is a delicate balance, with modifier molecules constantly moving in and out of the capsules. It has been proposed to anchor modifiers more firmly. One method has been to add the modifier to the fragrance dispersion as the capsule walls form, so that the modifier becomes entangled with the forming walls, thus anchoring the modifier in place. This has been successful in some, but not all, cases. Furthermore, some modifiers can interact with certain perfume components in a way that alters the nature of the perfume and, therefore, the desired hedonic effect. Another proposal has been to covalently link the modifier to the capsule wall. This has the advantage that the capsules can be formed and then subsequently modified. However, it depends on the presence of complementary reactive groups on both the wall and the modifier, which is not usually the case. One proposed way to overcome this is to use a linking compound, i.e., a compound that has functionality for both the capsule wall and the modifier. Examples of this technique can be found in the international publications WO 2006 / 1172902, WO 2010 / 1424012, and WO 2018 / 149775. It has now been found that it is possible to effectively secure microcapsules substantially to substrates by means of a new mechanism. Therefore, a method is provided for covalently linking a modifier to the wall of a polymeric microcapsule, such wall comprising entities capable of reacting with acrylic fractions, comprising supplying a linker compound to the wall to which the modifier is subsequently attached, the linker compound having formula I: pfrfrQnn / zznz / E / YiAi in which n=30; Ri, R2 and R3 are selected independently of the following remainders: Ri 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. In addition, the description also provides microcapsules prepared by a process like the one described above. In particular modalities, n is 1-23, 1-20, 1-15, 1-10 and 1-5. In one particular embodiment, the bonding compound is a compound with an acrylate residue (CH2=CH.COO-) at one end and a methacrylate entity (CH2=C (CH3) .COO-) at the other, i.e., one of R and R3 is H and the other CH3). In another particular modality, Ri and R3 are both H or both CH3 and X are O, the other remains being as described above. In another particular modality, the bonding compound is a compound of Formula II or Formula III: oo III The compound in Formula II is 3(acryloyloxy)-2-hydroxypropyl methacrylate. The polymer that makes up the capsule wall can be any polymer comprising entities capable of reacting with acrylic moieties, that is, moieties comprising the prop-2-enoyl group CH2=CH-CO-. The entities that will react with the acrylic moieties are nucleophilic groups, for example, primary and secondary amines, hydroxyl, thio and phosphine (H-PR2), hypophosphites H2P(O)OH, and phosphonates of the type H-PO(OH)2 or H-PO(O>2). Particular examples are polymers that incorporate amine groups, such as urea and melamine-formaldehyde resins and polyurea. The modifier can be any suitable modifier capable of reacting with the bonding compound to form a covalent bond and thus be permanently attached to the capsule surface. Typical examples of modifiers include polysaccharides such as mannan, glucan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan, and mixtures thereof. The process of the invention is carried out by adding the linking compound to a capsule suspension, followed by the modifier, the linker, and an initiator. The degree of grafting of the modifier, i.e., the proportion of added modifier that binds to the capsules, pfrfrQnn / zznz / E / YiAi, can be determined by any suitable method, for example, by gel permeation chromatography or viscosity measurement. A typical procedure for preparing samples for GPC for determining the degree of grafting is described in the examples. Depending on the nature of the modification, the modified capsules are easily redispersed, if necessary, and have improved substantivity on the desired substrates. The modified capsules have a much greater substantivity for the substrates, since a greater proportion of the capsules will adhere to the substrate, thus providing a much more enhanced olfactory experience. The microcapsules described above can be incorporated into any treatment preparation applied to a substrate. This could be, for example, a laundry preparation, such as a laundry detergent (powder or liquid) or a fabric conditioner or softener. Therefore, the description also provides such a treatment preparation. Furthermore, it provides a method for enhancing the substantivity of a substrate with microcapsules applied to the substrate as part of a treatment preparation, the microcapsules being prepared as described above. The description is further detailed with reference to the following examples, which describe particular modalities and are in no way intended to be limiting. All proportions are by weight. EXAMPLES Example 1 Preparation of urea-melamine-formaldehyde capsule A containing perfume with hydroxypropylcellulose graft. pfrfrQnn / zznz / E / YiAi The following materials and quantities were used for 100 g of suspension. Component Mass / g Perfume 27 Drinking grade water 42 Zemac™ E4001 2.85% 20 Urea 1 NaOH 30% 0.5 Luracoll™SD2 2 3-(acryloyloxy)-2-hydroxypropyl-methacrylate 0.1 Klucel™3 4 Potassium persulfate 4% 1 Ethylene urea 30% 4 Total 9 9.6 1. Alternating copolymer of ethylene and maleic anhydride 2. Polymethylol-melamine precondensate 3. Hydroxypropylcellulose Dispersion M CS Prior to capsule preparation, a 2.85% solution of hydrolyzed ZeMac™ E400 in water was prepared. Similarly, a hydroxypropylcellulose dispersion was prepared one day in advance by dispersing hydroxypropylcellulose in a stirred glycerin / water solution at room temperature. The reactor temperature was adjusted to 35°C, and then the following were added: water (10 g), Zemac™ E400 prepared as before, and urea. 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 perfume was added, and stirring continued at 35°C. A portion of Luracoll™ SD (1.4 g) was added and the temperature was increased to 88°C. This temperature was maintained for 30 minutes, at which point the remainder of Luracoll™ SD (0.6 g) was added and the temperature was maintained. 3-(Acryloyloxy)-2-hydroxypropyl methacrylate and HPC were added while stirring and temperature were maintained. This was followed by the addition of potassium peroxodisulfate, and the temperature was maintained. The remaining water and ethylene urea were added before cooling the reaction mixture. Capsule characterization: solid content 32%, expected 33%; dso = 18 pm; Viscosity at 5 / 21 s-1(25°C) = 3000 / 1500 mPa.s; HPC grafted = 40%. pfrbQnn / zznz / E / YiAi The degree of grafting was determined by the following method: One part by volume of the capsule suspension (typically 10 mL) was diluted in two parts by volume 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 resuspended in pentane and sonicated again for 20 minutes. The solid was filtered and rinsed twice more with pentane. The whitish solid was collected from the filter and air-dried. A calculated amount of this powder (40–50 mg) was suspended in 5.0 mL of DMF prepared as the eluent for gel permeation chromatography (0.1 mol / L of LiBr was dissolved in DMF, and this solution was filtered first through a 0.45 µm filter, and then through a filter with a pore size of 0.2 µm). This 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. Separation was performed there using three columns (Waters Styragel 4, 5, and 6, all 7 inches).8 x 300 mm), covering a total molecular weight range up to 6 x 10⁶ g / mol. The detection system consisted of a Heleos II Dawn8+ multi-angle laser light scattering detector (MALLS) and a differential refractive index (dRI, Optilab T-Rex) (both from Wyatt Technologies), enabling the detection and quantification of the residual (non-grafted) surface modifier. Separation conditions: Flow rate 0.5 mL / min, 50°C, DMF / LiBr pfrfrQnn / zznz / E / YiAi. 0.1 M as eluent. This allowed the determination of the recovery of the free, non-grafted polymer, and the difference from the total polymer used for grafting produces the amount of grafted polymer. Example 2 Preparation of a urea-melamine-formaldehyde capsule B containing perfume using a polysaccharide other than HPC. Example 1 was repeated following exactly the same procedure except that the HPC was replaced by 0.5 g of a modified polysaccharide with ammonium functionalities. Characterization of the capsule suspension: solid content 32.4%, expected 33.5%; dso = 7 pm; Viscosity at 5 / 21 s“1(25°C) = 4000 / 1900 mPa.s; Example 3 Preparation of a C-shaped urea-melamine-formaldehyde capsule containing perfume with a hydroxypropylcellulose graft. In a closed reactor equipped with a mechanical stirrer, 26 g of ZeMac™ E400 hydrolyzed solution (2.9%) and 16 g of water were introduced at room temperature and stirred for 3 minutes at 200 RPM. Stirring was then stopped, and 33 g of perfume were added to the reactor, followed by 0.2 g of Dynasylan™ AMEO (3-aminopropyltriethoxysilane). Stirring (700 rpm) and heating were then initiated, and after reaching 35°C, the pH was adjusted to 6.0 using an aqueous NaOH solution. Stirring was continued for 1 hour at 35°C, at which point the pH was adjusted to 4.6 using an aqueous formic acid solution. Luracoll SD (1.2 g) and urea (0.8 g) were added to this stirred solution and heating was increased to reach 90°C. 30 minutes after reaching 90°C, 0.7 g of Luracoll were added and heating was continued for another 120 minutes. 0.1 g of 3-(acryloyloxy)-2-hydroxypropyl methacrylate and 0.55 g of HPC were added to the reactor, followed by potassium peroxodisulfate (KPS, 1 g of a 4% aqueous solution) in two portions over the next hour. After another hour, 4 g of a 30% aqueous ethylene urea solution were added, followed by approximately 16 g of water. The suspension was cooled to 25°C for 1–2 hours. Characterization of the capsule suspension: dso = 17 pm; Viscosity at 5 / 21 s-1(25°C) = 2800 / 1800 mPa.s; % HPC grafted * 60%. Example 4 pfrbQnn / zznz / E / YiAi Preparation of a polyurea D capsule containing perfume with hydroxypropylcellulose graft. Name Mass Water 51 g Floset™ Solution DP CAPS 371L1 13 g Name Mass Perfume 32 g Lupasol™ G1002 commercial 1.5 g 3-(acryloyloxy)-2-hydroxypropyl-methacrylate 0.2 g Desmodur® Wl3 0.3 g Bayhydur® XP25474 0.1 g HPC (hydroxypropyl cellulose) 0.1 g AIBN 0.12 g KPS5 0.12 g Ammonia 1.5 g 1. emulsion stabilizer 2. polyethylene imine 3. Monomeric cycloaliphatic diisocyanate 4. hydrophilic aliphatic polyisocyanate 5. Potassium persulfate In a reactor equipped with a mechanical stirrer, at 25°C and with gentle stirring, the following were introduced: water, Floset DP CAPS 371L and Bayhydur XP2547, after which the stirring speed was increased to 1300 rpm. Desmodur isocyanate and perfume were added simultaneously to this stirred mixture and stirring was continued for 30 minutes. The Lupasol™ G100 solution in water was added to the stirred mixture and heating was started, gradually raising the temperature from 25°C to 85°C for three hours, where it was maintained for another two hours. Next, 3-(acryloyloxy)-2-hydroxypropyl methacrylate was added, followed by HPC solutions (hydroxypropylcellulose, KPS and AIBN at 30-minute intervals). The temperature and stirring were maintained for another hour, at which point ammonia was added. After brief stirring, the mixture was cooled to 25°C. Characterization: solid content 43.2%, expected 42.1%, dso: 14.8 pm; HPC graft: 60-70% Example 5 pfrbQnn / zznz / E / YiAi Preparation of resorcinol-melamine-formaldehyde capsule E containing perfume with hydroxypropylcellulose graft. Name Mass Resorcinol 0.7 g Floset™ DP / CAPS 371 L 10 g Luracoll™ SD 1.9 g Perfume 3.6 g Formic acid 3.6 g 3-(Acryloyloxy)-2-hydroxypropyl methacrylate 0.1 g HPC 0.5 g KPS 0.1 g Water 37 g Name Mass Water 37 g 30% Aqueous Ethylene Urea 10 g Water, resorcinol, Floset™ DP / CAPS 371L, and Luracoll™ were added to a reactor equipped with a mechanical stirrer. The mixture was placed in SD and agitation was started at 400 rpm. Once the mixture was homogenized, the perfume was added and the agitation speed was increased to 950 rpm. Using formic acid, the pH was adjusted to 3.5–4.0. The temperature was gradually increased to 75°C and held there for 1 hour. The pH was then adjusted again with formic acid, and agitation was maintained at 75°C for another hour. 3-(acryloyloxy)-2-hydroxypropyl methacrylate and HPC were added to the reactor at 75°C, followed by KPS for the next hour. Stirring at 75°C was continued for another hour. Ethylene urea solution was added, and stirring continued at 75°C for another hour, at which point heating was stopped and the mixture was cooled to 25°C. Capsule characterization: dso = 22.7 pm; solid content 31.7%, expected 33.3%; % HCP graft: -40%. Example 6 Preparation of urea-melamine-formaldehyde F capsule containing perfume without surface modification For comparison purposes, a capsule F was synthesized following the procedure described in Example 1, but omitting the grafting step; that is, neither 3-(acryloyloxy)-2-hydroxypropyl methacrylate nor KPS were added to the HPC reaction. This is an example of a capsule without surface modification. Capsule characterization: solid content 30%, expected pfrfrQnn / zznz / E / YiAi 31%; dso = 17 pm; Viscosity at 5 / 21 s-1(25°C) = 1200 / 700 mPa.s. Example 7 Preparation of a G-capsule of urea-melamine-formaldehyde containing perfume with surface modification by xyloglucan by co-trapping For comparison, capsule G was synthesized following the procedure of Example 1, but omitting HPC, 3-(acryloyloxy)-2-hydroxypropyl methacrylate, and KPS. The difference from 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 surface modification is achieved by co-trapping the modifier in the outer layer of the capsule surface. Capsule characterization: solid content 32%, expected 33%; dso = 17.5 pm; Viscosity at 5 / 21 s 1 (25°C) = 2800 / 1100 mPa.s. Example 8 Preparation of H capsule of urea-melamine-formaldehyde containing perfume with surface modification by hydroxypropylcellulose by co-entrapment For comparative purposes, capsule H was prepared following the procedure in Example 1, but omitting the 3-(acryloyloxy)-2-hydroxypropyl methacrylate and KPS. HPC (same amount as in Example 1) was added along with Luracoll at 88°C. pfrbQnn / zznz / E / YiAi This is an example of a capsule in which the surface modification was carried out by co-trapping the modifier in the outer layer of the capsule surface. Capsule characterization: solid content 19%, expected 33%; dso = 17 pm; Viscosity at 5 / 21 s-1(25°C) = 3000 / 1500 mPa.s; HPC grafted ~ 20%. The low solids content measurement indicates that the capsules cannot withstand drying; that is, the encapsulated fragrance escapes from the capsules as they dry, either because they break mechanically or because the coatings are not sufficiently impermeable to prevent fragrance evaporation. Either way, this represents an example of poor fragrance encapsulation, possibly resulting from interference of the modifying molecule with the encapsulation process. Example 9 Demonstration of the need for the components required for the modifier graft. Example 1 was repeated, omitting one or more molecules used in the grafting step (indicated by * for the absence of the molecule and + for the presence of the molecule). Therefore, entry 1 in the table below represents a synthesis in which only HPC was added and the linker and residue initiators were omitted. Entries 5–7 in the table describe a variation of the residue initiator and its impact on grafting. The percentage of grafting was determined by the method described in Example 1. No. HPC linker KPS AIBN 2,2'-azobis-(2-methylprop¡oamid¡n)- dihydrochloride HPC recovery (%) HPC grafting (%) 1 - + - - - >95 0 2 - + + - - >95 0 3 + + - - - >95 0 4 + + + - - -50 50 5 + + - + - >70 30 6 + + + + -50 50 7 + + - - + -50 50 It can be seen that: - In Nos. 1-3, there is almost no HPC grafting (recovery is almost complete), which shows that the absence of one of the modifiers (HPC), linker or initiator leads to almost non-existent grafting. - In No. 4 (identical to Example 1), there is a 50% graft, a substantial result. - In No. 5, the use of the AIBN (oil-soluble) starter gives a slightly worse result than in No. 4, but still acceptable. - In No. 6, the combination of the two initiator tapes showed no improvement over the KPS used alone. In No. 7, the use of the initiator 2,2'-azobis-(2-methylpropionamidin)-dihydrochloride gives a result equal to that of No. 4. Example 10 Demonstration of the olfactory benefit of HPC grafting onto polyester substrate (T-shirts) Polyester is known to be a difficult substrate for fragrance deposition, especially for encapsulated fragrance deposition, probably due to the smooth, hard surface of polyester fibers, which offers a very small contact area for the fragrance capsule, requiring high adhesion energy between the two objects in order to achieve high olfactory performance. Samples of liquid detergent containing capsules A, C, F, G, and H, prepared in Examples 1, 3, 6, 7, and 8 respectively, were prepared by dispersing a suspension of these capsules in identical quantities (50 g) of a liquid detergent base. The fragrance concentration level was identical in all samples. Each sample was subjected to a wash cycle in standard European front-loading washing machines with five cotton towels and three polyester T-shirts, with additional cotton sheets to complete the 5 kg washing machine load. After drying, the performance of the post-rubbing fragrance booster was evaluated by observing the perceived fragrance intensity level after gently rubbing the substrate to crush the capsules and release the fragrance. The fragrance was evaluated by a panel of 7 expert evaluators. Capsule G was taken as the standard (one in which the modifier was incorporated using the trapping method recognized in the art). The olfactory evaluation was based on a scale of: - no difference or worse than the standard capsule - slightly stronger than the standard capsule - significantly stronger than standard capsule 4 - considerably stronger than the standard capsule. The figures were averaged and the results are shown in Figure 1. It can be seen that the performance of the samples in which the covalent shape modifier was grafted (A and C) was significantly higher than that of the other samples. Capsule I, with its low performance, demonstrates that the co-trapping route to surface modification is not the way to introduce this particular modifier. While capsule G can be prepared by co-trapping, its performance is even lower than that of A and C, but higher than the performance of unmodified capsule F. Therefore, this example demonstrates not only the benefit of modifying the capsule surface for greater olfactory performance (F vs. A, C, and G), but also highlights the advantage of covalent grafting over the co-trapping strategy, especially when the molecules of interest cannot be used in the trapping method. pfrfrQnn / zznz / E / YiAi Example Capsule Note Polyester T-shirt Comment A 1 3 Covalent graft (HPC) C 3 4 Covalent graft (HPC) F 6 1 No modifier G 7 1 Co-trapping (xyloglucan) H 8 1 Co-trapping (HPC) pfrfrQnn / zznz / E / YiAi It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

1. A method for covalently linking a modifier to the wall of a polymeric microcapsule, said wall comprising entities capable of reacting with acrylic moieties, comprising the arrangement in the wall of a linking compound to which the modifier is subsequently linked, the linking compound having Formula I: characterized in that: n=la 30; Ri, R2 and Ra are independently selected from the following moieties: Ri 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.

2. Method according to claim 1, characterized in that n is selected from 1-23, 1-20, 1-15, 1-10 and 1-5.

3. Method according to claim 1, characterized in that the linking compound is a compound with an acrylate residue (CH2=CH.COO-) at one end and a methacrylate entity (CH2=C (CH3) .COO-) at the other.

4. Method according to claim 1, characterized in that Ri and R3 are both H or both CH3 and X is O.

5. Method according to claim 1, characterized in that the bonding compound is a compound selected from compounds of Formula II and Formula III:

6. Method according to claim 5, characterized in that the bonding compound is 3-(acryloyloxy)-2-hydroxypropyl methacrylate.

7. Method according to claim 1, characterized in that the wall of the polymeric microcapsule comprises amine groups.

8. Method according to claim 7, characterized in that the polymeric material of the microcapsule wall is selected from aminoplasts, such as urea and melamine-formaldehyde resins, and polyurea.

9. Method according to claim 1, characterized in that the modifier is selected from at least one polysaccharide.

10. Method according to claim 9, characterized in that the polysaccharide is selected from mannan, glucan, glucomannan, xyloglucan, hydroxyalkylcellulose, dextran, galactomannan and mixtures thereof.

11. Method according to claim 1, characterized in that the microcapsules contain fragrance.

12. Microcapsules, characterized in that they are prepared by a method in accordance with claim 1.

13. Treatment preparation, particularly a laundry preparation, characterized in that it comprises microcapsules according to claim 12.

14. Method for improving the substantivity of a substrate of microcapsules applied to the substrate as part of a treatment preparation, characterized in that the microcapsules are prepared according to the method of claim 1.

15. Method according to claim 14, characterized in that the treatment preparation is a washing product and the microcapsules contain fragrance.