JP2003001100A - Method for producing cationic microcapsules - Google Patents

Abstract

[PROBLEMS] To invert the charge of an anion or amphoteric microcapsule to a positive charge. A method for denaturing an anion or amphoteric microcapsules is prepared by adjusting a compound having a positive charge without causing agglomeration, flocculation, or precipitation, and further, without altering these microcapsules. While adding. These compounds and treatment methods are described. The produced microcapsules have an excellent affinity for textile fibers, skin, paper and hair and are used, for example, for fixing cosmetics, perfumes, encapsulating agents and physiological products.

Description

Detailed Description of the Invention

At present, microcapsules are used for papermaking, textiles,
It is widely used in various fields such as cosmetics, pharmaceuticals and food industry.

[0002] A process for producing microcapsules filled with hydrophobic active ingredients comprises the steps of dispersing the active ingredients in water as fine droplets and then coating these droplets with a polymeric shell. This latter step uses various techniques based on many patents. To give a few examples of these patents, the 1996 ARO
Polyamides described in U.S. Pat. No. 3,270,100, polyurea-polyurethanes first described in 1969 NCR British Patent No. 1,142,556, or 1964. Ivy of the year
There is a very widely practiced interfacial polymerization in the art of manufacturing microcapsules with an outer shell made of polyester, which was first described in British Patent No. 950443 to IBM.

By in-situ polymerization or polycondensation, mainly
Microcapsules having an outer shell composed of aminated urea or melamine type resin are manufactured from a water-soluble precondensate. This technique has already been described in 3965 (3M) British Patent No. 989264.

[0004] Complex coacervation, which becomes a wall composed of gelatin complex, has already been reported in 19
US Patent No. 2,8 of 57 NCR (NCR)
It was first described in No. 00,457.

These first patents, advances in technology, and successive improvements in these various methods have resulted in
It was the basis of many patents.

All of these improved prior art techniques produce a high quality microcapsule with a reduced number of steps.
Since the microcapsules produced by this conventional technique have a negative charge as a whole under normal use conditions, they can be classified as anionic or amphoteric microcapsules.

[0007] There are few techniques that can produce cationic microcapsules, and there are techniques that are difficult to use and difficult to control. These techniques are described, for example, in US Pat. No. 5,753,264.

The object of the present invention is to start substantially from the well-known microcapsules as described above, after the so-called encapsulation process, to subject these microcapsules to a post-treatment so that they are substantially under practical conditions. It is to produce microcapsules having a charge that becomes a cation.

The advantages of the present invention are that conventional encapsulation techniques can be used and that the manufactured microcapsules require a field or positive charge in which positive charge is effective, as exemplified below. It can be used in the field.

Pharmaceutical and Cosmetic Fields It is well known in these industries that positively charged products readily adhere to the skin or hair. By utilizing this property, it is possible to deposit and then release active ingredients such as vitamins, ultraviolet filters, drugs, and insecticides, insecticides, acaricides, coloring agents, antiperspirants and the like.

Textile Field The sticking to anionic fibers is significantly promoted by the positive charge. Cation microcapsules have a strong affinity for this type of fiber, especially under conditions suitable for the anionic character of the anionic fiber. Examples of this type of fiber are cellulosic fibers such as cotton, polyamides, wool, polyesters and polyurethanes. Cationic microcapsules can be used, among other things, to fix and then release perfumes, active cosmetics or pharmaceuticals, fungicides, insecticides and other useful agents. The strong affinity for these fibers improves the washfastness of the fibers, eliminates the need for binders, or at least reduces the amount of binder used, thereby promoting release of the active ingredient.

Field of Paper Making Cationic capsules have an excellent affinity for cellulosic fibers and are very well incorporated inside and on the surface of cellulosic fibers. Clean tissue, anti-dirt paper,
The application to toner manufacturing etc. becomes easy.

More generally, flocculation (flo
Cement) and a medium mainly composed of cationic compounds such as a textile fiber conditioner that makes it difficult to incorporate anionic microcapsules that cause viscosity changes.

Further, the deodorant, physiological product, food preparation, or chemically active ingredient can be encapsulated in microcapsules.

As is well known to manufacturers and persons skilled in the art, it is very difficult to introduce a positive charge into the anionic medium, and usually the higher the molecular weight of the medium used, the more pronounced the precipitation or flocculation. Cause to.

The technique described herein does not change the fragile and complex product microcapsules by the totally unexpected method of controlled addition of compounds having opposite charges to the microcapsules. , Its charge can be changed, and agglomeration (agg
lomeration), flocculation and precipitation, and their shape, let alone depositing these compounds on the outer shell of the microcapsules without degrading the quality and becoming part of the outer shell. Is shown to improve.

Of course, various encapsulation techniques can be utilized to produce microcapsules that are easy to use in the process of the present invention.

Therefore, when a high molecular weight anionic polymer which is not incorporated in the outer shell of the microcapsule is present in the microcapsule suspension, the flocculation remarkably remarkably occurs during the introduction of the cationic compound. As a result, problems such as protective colloids and purification steps which will be described in detail later occur.

Similarly, various compounds existing in the medium and involved in encapsulation, charges not fixed in microcapsules, density of negatively charged atoms, presence of amphoteric molecules, and more or less porous. The outer shell structure of the hydrated microcapsules influences the process.

The diameter of the microcapsules that facilitate the method of the present invention can vary widely, but generally ranges from 0.1 to 200.
More favorable results are obtained with an average diameter in the range of 1 to 200 microns.

The first step of the method of the present invention is to place the microcapsules under the preferred conditions and environment. That is,

A pH condition that shifts the ionic equilibrium from a state in which anions are dominant in an ordinary acid medium.

Optimal concentration conditions that avoid flocculation and agglomeration.

First, it is necessary to dilute the microcapsules and wash the microcapsules to remove the ionic polymers present in the medium from the microcapsules.
This step involves decanting or suspending according to the density of the dispersed phase, followed by removal of the liquid phase, replacement with water, centrifugation, filtration or ultrafiltration, and more general solid / liquid separation methods. Can be implemented by:

When the process is very delicate, the addition of protective colloid is very effective.

Effective protective colloids in this case are, in particular, the known compounds which have an activity selected by virtue of their nonionic character. Some of the most well-known among them are polyvinyl alcohol and its derivatives,
Cellulose ethers or esters, polyvinylpyrrolidone and its derivatives, polyacrylamide and methylacrylamide and their derivatives, natural gums (guar, xanthan, alginate, etc.), and mixtures of these polymers.

Under these conditions, the microcapsules are vigorously stirred and the cationizing reagent is added slowly until the desired positive charge is reached. The amount of this reagent will be determined by the desired effect and the optimum amount should be determined by the respective application. If the amount of this reagent is too small, the desired charge cannot be obtained. On the other hand, if this amount is too large, various reagents attempting to reach the anion site compete with the reagent fixed to the anion site, and the effect is reduced.

Compounds that are effective in reversing charge and used in the present invention must have the following properties. That is, it is generally water-soluble or rapidly finely dispersed to reach appropriate sites quickly. Therefore, emulsions or solutions in a solvent that is compatible with water are also suitable.

The optimum molecular weight of this compound should not be too large or too small, depending on its chemical structure. If this molecular weight is too high, flocculation of the formulation will occur. On the contrary, if the molecular weight is too small, it becomes difficult to adhere to the wall surface of the microcapsule, and the effect is lost.

The molecular weight of compounds suitable for carrying positive charges ranges between 100 and 100,000,000, preferably between 500 and 10,000,000, with one or a few in its backbone or side chains. It has one cationic group, that is, a group in the form of a quaternary ammonium compound, which is found in most industrial products.

The molecule preferably contains one or several of these cationic groups, for example alcohols, ethers, esters, ketones, amides, imides, amines, silanols, aromatic or saturated cyclic groups, heterocycles. It is present in the form of polymers having groups such as cyclic groups, sulfur atoms which are somewhat oxidized, saturated or unsaturated bonds. Those skilled in the art can use these polymers to adjust the solubility of the compound for the outer shell of the microcapsule and the support for fixing the microcapsule, and thus the production control and the selling price. There is.

Preferred polymers are cellulose, starch,
Protein, alginate, guar gum, carrageen
en), carob, xanthan, and other well known natural product sources. Furthermore, the preferred polymers may be of synthetic origin. Examples of the most useful of these polymers are polyamide, poly (meth) acrylamide, polyether, polyester, polyoxymethylene, silicone, polyurethane, polyvinyl ether,
Polyethylene (propylene) oxide, polyvinyl alcohol and acetate, polyvinyl formal or butyryl, polyvinyl methyl ether, polyvinyl pyrrolidone, polyvinyl (methyl) oxalidone, polyvinyl amine, polyvinyl pyridine, polyimidazoline, and, for example, melamine-formaldehyde resin or urea formaldehyde. It is a reactive polymer such as a resin.

The polymers which can be used are further specified, for example, poly (diallyldimethylammonium chloride), poly (N, N-diethyl-3,5-methylenepiperidinium chloride), poly (dimethylimino) trimethylene (dimethylimino). Hexamethylene bromide, poly (4-vinylbenzyltrimethylammonium chloride), poly (2-vinylpiperidine chloride), polyDADMAC and similar polymers, which are more cationic polymers.

The polymers exemplified above are not limited thereto but also include copolymers in which several of these polymers are combined. To illustrate this, INCI
Poly-quaternary compound with product name 1 to 20, and 2
4 and 47, which are mainly used in the cosmetics industry.

All of these polymers have a variety of effects. In particular, a polymer having both a quaternary amine group and a free amine or amide group can obtain an important effect.

These polymers have the advantage that the charge density is not too high compared to fully cationized structures. Therefore, these compounds have the advantage that they can be easily added to the suspension of microcapsules, especially when diluting the microcapsules in an acidic medium, or at least temporarily supplementing the amounts. It has the advantage that it can be easily added to the suspension of the microcapsules even when in use. By this, in the usual way,
The affinity of the surface of the textile fiber, hair, skin, etc. for the anionic support agent becomes stronger.

Some of these well-known polymers are exemplified below. Partially cationized melamine resins, cationic polyamides that can be modified with epichlorohydrin, polyacrylamines, polyethylene-imines, partially quaternized polymers or copolymers of polyvinylpyrrolidones. , Polyvinyl (methyl) oxazolidone, polyvinylamines, polyvinylpyridines, and polyimidazolines.

A few examples of commercially available cationic polymers specialized in cosmetics under the trade name INCI are described below. Polyquaternium 2 (Rhone Poulenc Mirapol A 15) Polyquaternium 7 (Calgon Merquat 550) Polyquaternium 16 (BASF Luviquat FC) Polyquaternium 17 (Rhone Poulenc Mirapol AD1) Polyquaternium 18 (Rhone Poulenc Mirapolteraf 28 ISP) Polyquaternium 18 HS-100) Polyquaternium 32 (Allied colloide Salcare SC6
3) Polyquaternium 33 Polyquaternium 44 (Luviquat MS 370 from BASF) Polysilicone 9 (Elastomer OS from Kao)

An example is a high molecular weight product which does not contain a polymer but which exerts a similar effect and sticks. Quaternium 45 (Ikeda's Luminex) Quaternium 61 (Scher's Schercoquat DAS) Quaternium 78 (Finetex's Finsoft HCM 100)

Example 1 Produced according to US Pat. No. 5,635,211 and containing a perfume having a density of 0.85, a solid content of 40%, a diameter of 20 μm.
Polyurea type (interfacial polymerization) microcapsules 500ml
Was diluted with 500 ml of water with stirring.

The microcapsules were placed in a decanted ampoule and left for one day.

The lower liquid phase was removed and replaced with 400 ml of pure water.

Gently stir to homogenize the medium and pour with acetic acid.
H was set to 5.

With stirring, 6 g of Colacral VL (a vinylpyrrolidone copolymer of BASF) was added.

When the mixture was homogeneous, 15 g of Gafquat HS100 from ISP was added slowly with vigorous stirring.

The prepared microcapsules had enhanced cation character and easily fixed to the anionic support in acidic medium.

Example 2 Manufactured according to French Patent No. 90.08092,
35% solids containing a fragrance of density 1.05, diameter 10
μ melamine type (in-situ polymerization) microcapsules 500m
1 was diluted with 500 ml water with stirring.

The microcapsules were placed in a cylinder and left for one day.

The liquid phase of the supernatant was removed and replaced with pure water.

The medium was homogenized by gentle stirring.

After performing the precipitation operation again to remove the supernatant phase, 400 ml of water was added to make the water level the same, and the pH of the homogenized medium was adjusted to 4.5 with formic acid.

While stirring vigorously, hydroxypropyl-
1.5 g of guar (N-Hanse HP from Hercules) was added.

When the mixture was homogeneous, 30 g of Calgon's Merquat 550 was added with vigorous stirring.

The prepared microcapsules had enhanced cation character and easily fixed to the anionic support in acidic medium.

Example 3 500 ml of gelatin type microcapsules produced by complex coacervation according to the patent EP-B-339-866 and having a solid content of 25% encapsulating a perfume with a density of 1.05 and an average diameter of the cell star of 20 μ were used. , While stirring, 2
Diluted with 00 ml water.

The microcapsules were placed in a cylinder and left for one day.

The liquid phase of the supernatant was removed and replaced with pure water.

The medium was homogenized by gentle stirring and the pH was brought to 5.0 with acetic acid.

With vigorous stirring, 1.5 g of hydroxyethyl-cellulose (Natrosol 250M from Hercules) was added.

When the mixture was homogeneous, 10 g of Hercules Kymene EX 2012 (polyamine modified with epichlorohydrin) was added with vigorous stirring.

The prepared microcapsules had enhanced cation character and easily adhered to the anion support.

Example 4 Produced by complex coacervation according to patent EP0674942B1, the mean diameter of the capsules is 50 μm.
Then, the pH of 500 ml of gelatin type microcapsules having a solid content of 35% in which a bactericidal agent was encapsulated was adjusted to 5.5.

1.3 g of hydroxyethyl-cellulose (Natrosol 250M from Hercules) was added with vigorous stirring.

Once the mixture was homogeneous, again with vigorous stirring, 18 g of polyvinylpyridine partially reionized to 45% in alcohol (from Reuilly Corp.).
Reilline) was added.

The prepared microcapsules had enhanced cation character and were easily anchored to the anion support.

Example 5 The capsules produced by complex coacervation according to the patent EP 0674942B1 have an average diameter of 8 μ and a solid content of 35% and are colored with a blue colorant which dissolves in the lips for the test. 500 ml of gelatin type microcapsules encapsulating a cosmetic hydrated compound were taken out at pH 3.9 before raising the pH.

With stirring, 5 g of Colocral VL was added.

When the mixture was homogeneous, 10 g of polyamine (Lufasol G35 from BASF) was added with vigorous stirring.

The microcapsules produced had enhanced cation character and easily stuck to the anion support.

These microcapsules are compared with the first non-cationized microcapsules. For this purpose, 2 g of 35% microcapsules were added at 40 ° C for 20
Poured into 0 ml of water and adjusted to pH 4 with hydrochloric acid. In this medium, a piece of fiber cloth of 20 cm 2 is stirred for 30
Soaked for a minute.

Then, the cloth piece was taken out and dried, and the color condition was evaluated in the range of 0-10. Blank first, 1
0 represents the best result.

[0072] This result shows a significant advantage of the capsule of the invention.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) D06M 13/46 B01J 13/02 K 4L055 D21H 21/54 E (72) Inventor Hubbard Gerard France F-77780 Bron-Mallot Rue de Fugere 31 F Term (Reference) 4C076 AA64 DD49A DD52A EE01A EE16A EE32A EE42A FF70 GG29 4C083 DD14 4G005 AA01 AB21 BA02 BA05 BB01 EA05EA42EA45EA45EA45EA15EA45DD45BA05EA45DD0515 BA49 BB02 BB15 BB24 BB52 BB53 BC45 BC46 CA54 DA09 EA31 4L033 AC10 AC15 BA85 4L055 AG94 AG99 AJ08 FA30 GA29

Claims (9)

[Claims] 1. A method for producing a microcapsule having a positive charge, which comprises producing an anionic or amphoteric microcapsule and then having a cationic group which reacts with the anionic or amphoteric microcapsule. Alternatively, the method is carried out in two main steps, the inversion of its charge or the enhancement of its cationic character by several compounds. 2. The cationic compound for reversing charges or enhancing its cationic property contains one or several quaternary nitrogen atoms in its molecule. Method. 3. A compound for reversing charge or enhancing its cationic property has a molecular structure containing, in addition to a quaternary nitrogen atom, one or several non-quaternary amine and / or amide groups. The method according to claim 2, wherein 4. A compound which inverts electric charge or enhances its cationic property has a molecular weight of 100 and 10,000,000.
A polymer which is between 0 and 3.
Alternatively, the method described in 3. 5. The method according to claim 1, 2, 3 or 4, characterized in that the microcapsules are produced by complex coacervation. 6. A method according to claims 1 to 4, characterized in that the polymer used for charge reversal is added when the pH of the microcapsules is acidic. 7. The step of charge reversal or enhancement comprises the addition of a protective colloid to prevent flocculation and agglomeration of anionic or amphoteric microcapsules during the addition of the cationic compound. Method according to claims 1 to 6, characterized in that it is carried out in advance. 8. The method according to claim 1, which contains a fragrance or a deodorant, a cosmetic active agent, a colorant, a pharmacologically active agent, a physiological product, a food compound, or a chemical active agent. Micro capsule. 9. A method of immobilizing microcapsules comprising adding the microcapsules produced in claim 8 to an acidic medium in a medium containing a support intended to receive the microcapsules.