SPHERICAL MICROPARTICLES

Abstract

The present invention relates to a composition of spherical microparticles composed of a wall material and at least one cavity that comprises a gas and/or a liquid, which have pores on the surface thereof, wherein the spherical microparticles have a mean particle diameter of 10-600 m and wherein at least 80% of those microparticles, the particle diameter of which does not deviate from the mean particle diameter of the microparticles of the composition by more than 20%, each have on average at least 10 pores, the diameter of which is in the range from 1/5000 to 1/5 of the mean particle diameter, and, furthermore, the diameter of each of these pores is at least 20 nm, wherein the wall material consists of a composition comprising at least one aliphatic-aromatic polyester and at least one additional polymer, wherein the additional polymer is selected from the group consisting of polyhydroxy fatty acids, poly(p-dioxanones), polyanhydrides, polyesteramides, polysaccharides and proteins, to a method for the preparation thereof and use thereof.

Claims

1.-16. (canceled)

17. A composition of spherical microparticles composed of a wall material and at least one cavity that comprises a gas and/or a liquid, which have pores on the surface thereof, wherein the spherical microparticles have a mean particle diameter of 10-600 m and wherein at least 80% of those microparticles, the particle diameter of which does not deviate from the mean particle diameter of the microparticles of the composition by more than 20%, each have on average at least 10 pores, the diameter of which is in the range from 1/5000 to 1/5 of the mean particle diameter, and, furthermore, the diameter of each of these pores is at least 20 nm, wherein the wall material consists of a composition comprising at least one aliphatic-aromatic polyester and at least one additional polymer, wherein the additional polymer is selected from the group consisting of polyhydroxy fatty acids, poly(p-dioxanones), polyanhydrides, polyesteramides, polysaccharides and proteins.

18. The composition of spherical microparticles according to claim 17, wherein the aliphatic-aromatic polyester is an ester of an aliphatic dihydroxy compound esterified with a composition of aromatic dicarboxylic acid and aliphatic dicarboxylic acid.

19. The composition of spherical microparticles according to claim 17, wherein the aliphatic-aromatic polyester is selected from polybutylene azelate-co-butylene terephthalate (PBAzeT), polybutylene brassylate-co-butylene terephthalate (PBBrasT), polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate (PBSeT) and polybutylene succinate terephthalate (PBST).

20. The composition of spherical microparticles according to claim 17, wherein the composition forming the wall material comprises at least one polymer having a glass transition temperature or a melting point in the range from 45 to 140 C.

21. The composition of spherical microparticles according to claim 17, wherein the wall material has a solubility in dichloromethane of at least 50 g/l at 25 C.

22. The composition of spherical microparticles according to claim 17, wherein the additional polymer is at least one polyhydroxy fatty acid.

23. A method for preparing a composition of spherical microparticles, comprising a) preparing an emulsion from water or an aqueous solution of a pore former as discontinuous phase and a continuous phase comprising a solution of at least one aliphatic-aromatic polyester and at least one additional polymer selected from the group consisting of polyhydroxy fatty acids, poly(p-dioxanones), polyanhydrides, polyesteramides, polysaccharides and proteins, in a water-immiscible solvent, b) emulsifying the emulsion obtained in a) in water in the presence of at least one dispersant to give a w/o/w emulsion having droplets with a mean size of 1-600 m, and removing the water-immiscible solvent at a temperature in the range from 20 to 80 C., c) separating off the spherical microparticles formed in method step b) and optionally drying the spherical microparticles.

24. A composition of spherical microparticles obtained by the method according to claim 23.

25. A carrier substance for filling with at least one aroma chemical comprising the composition of spherical microparticles according to claim 17.

26. The method according to claim 23, further comprising impregnating the optionally dried spherical microparticles with at least one aroma chemical.

27. A method for preparing an aroma chemical preparation, comprising impregnating the composition of spherical microparticles according to claim 17 with at least one aroma chemical.

28. The method for preparing an aroma chemical preparation according to claim 27, wherein the spherical microparticles are suspended in a liquid aroma chemical or in a solution of at least one aroma chemical.

29. An aroma chemical preparation obtained by the method of claim 26.

30. A composition comprising the aroma chemical preparation according to claim 29, wherein the composition is selected from perfumes, washing and cleaning compositions, cosmetic compositions, body care compositions, hygiene articles, food, food supplements, scent dispensers or fragrances.

31. A composition comprising the composition of spherical microparticles according to claim 17, in a proportion by weight of 0.01 to 99.9% by weight, based on the total weight of the composition.

32. A method for the controlled release of aroma chemicals comprising incorporating the aroma chemical preparation according to claim 29 into a perfume, washing and cleaning composition, cosmetic composition, body care composition, hygiene article, food, food supplement, scent dispenser or fragrance.

33. The composition of spherical microparticles according to claim 17, wherein the additional polymer is at least one polycaprolactone

Description

EXAMPLES

[0333] The examples below are intended to illustrate the invention in more detail. The percentages in the examples are weight percentages unless otherwise indicated.

Determining the Mean Particle Diameter in Aqueous Suspension/Emulsion Using Light Scattering:

[0334] The particle diameter of the w/o/w emulsion or the particle suspension is determined with a Malvern Mastersizer 2000 from Malvern Instruments, England, sample dispersion unit Hydro 2000S according to a standard measurement method which is documented in the literature. The value D[4,3] is the volume-weighted average.

Determining the Mean Particle Diameter of the Solid:

[0335] The microparticles are determined as powder with a Malvern Mastersizer 2000 from Malvern Instruments, England, including powder feed unit Scirocco 2000 according to a standard measurement method which is documented in the literature. The value D[4,3] is the volume-weighted average.

Determining the Pore Diameter:

[0336] The pore diameters were determined by means of scanning electron microscopy (Phenom Pro X). For this purpose, various close-up images were taken and these were retrospectively automatically measured using the ProSuite (FibreMetric) software from Phenom. The pores of a selected region of a particle were identified using the difference in contrast and the surfaces thereof were automatically measured. The diameter for each surface was calculated with the assumption that the surfaces were circular. (Sample size 100 pores).

[0337] In the context of the evaluation, only those pores whose pore diameter was at least 20 nm were taken into consideration. Depending on the particle size, the images were recorded, for larger particles with 1600- to 2400-times magnification, and for smaller particles with up to 8000-times magnification.

[0338] In order to determine the size of at least 10 pores, only those microparticles whose particle diameter does not deviate from the mean particle diameter of the composition of microparticles by more than 20% were taken into consideration.

[0339] The following assumption was made for evaluation of the number of pores based on the total surface area of the microparticle: Since these are spherical particles, the image only shows half the surface of the particle. If the image of a microparticle shows at least 5 pores whose diameter is at least 20 nm and whose diameter is in the range from 1/5000 to 1/5 of the mean particle diameter, then the total surface comprises at least 10 pores.

[0340] The evaluation was carried out according to the following procedure:

1. The mean particle diameter D[4,3] of the microparticles was already determined in the microparticle dispersion, using light scattering. The upper and lower limits of the particle diameter of the microparticles which are taken into consideration for determining the pores (20%) can be calculated from this.
2. The microparticle dispersion was dried.
3. From a sample, in each case 20 images showing multiple microparticles were taken by means of scanning electron microscopy.
4. 20 microparticles were selected whose particle diameter is in the range20% of the mean particle diameter of the microparticles. The particle diameter thereof was thus measured with the ProSuite (FibreMetric) software from Phenom.
5. The pores of each of these 20 microparticles were measured. For this purpose, the surface areas of the visible pores were measured automatically and the diameter thereof was calculated.
6. The individual values of the pore diameters were checked as to whether their diameter met the condition of being in the range from 1/5000 to 1/5 of the mean particle diameter and being at least 20 nm.
7. The number of pores meeting this condition was determined and multiplied by two.
8. It was verified whether at least 16 microparticles each had on average at least 10 pores.

Determining the Bulk Density:

[0341] The bulk density was determined as specified in DIN-EN ISO 60: 1999.

Determining the Water Content of the Microparticle Composition

[0342] Karl Fischer titration (DIN 51777): For this, approx. 2 g of powder were precisely weighed in and titrated with a 799 GPT titrino by the Karl Fischer method.

Example 1: Procedure for Preparing the Fillable Spherical Microparticles

[0343] Pore former solution: 0.54 g of ammonium carbonate were dissolved in 53.46 g of water (pore former).

[0344] Solution of the Aliphatic-Aromatic Polyester and of the Additional Polymer: 15.12 g of PBSeT and 6.48 g of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx)) were stirred into 270.0 g of dichlormethane and dissolved with stirring at 25 C.

[0345] In order to prepare the w/o emulsion, 54.0 g of pore former solution were emulsified in the solution of the aliphatic-aromatic polyester and the additional polymer for 1 minute at 5 000 rpm with a rotor-stator.

[0346] The w/o emulsion thus created was transferred into 419 g of a 0.8% by weight polyvinyl alcohol solution (having a degree of hydrolysis of 88 mol % and a viscosity of 25 mPa*s and proportion of carboxyl groups of 3 mol %) and likewise emulsified with shear and energy input (one minute at 300 rpm with an anchor stirrer).

[0347] The w/o/w emulsion produced in this way was subsequently further stirred at 150 rpm with an anchor stirrer, heated slowly to 40 C. while being stirred, and kept at this temperature for 4 hours with a nitrogen flow of 100 l/hour. Thereafter, the microparticle suspension was cooled to room temperature and filtered.

[0348] The mean particle diameter after filtration was 257 m. Water content: <0.5%

Examples 2 to 3

[0349] The procedure was analogous to example 1 with the difference that the polymer mixtures specified in Table 1 composed of aliphatic-aromatic polyester and a copolyester of 3-hydroxybutyrate and 3-hydroxyhexanoate [P(3HB-co-3HHx)] were used for the preparation of the fillable spherical microparticles.

Example 4

[0350] Pore former solution: 0.0225 g of ammonium bicarbonate were dissolved in 4.4775 g of water (pore former).

Solution of the Aliphatic-Aromatic Polyester and of the Additional Polymer:

[0351] 1.26 g of PBSeT and 0.54 g of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx)) were stirred into 22.5 g of dichloromethane and dissolved with stirring at 25 C. In order to prepare the w/o emulsion, 4.5 g of pore former solution were emulsified in the solution of the aliphatic-aromatic polyester and the additional polymer for 1 minute at 10 000 rpm with a rotor-stator.

[0352] The resultant w/o emulsion was transferred into 86 g of a 1% by weight polyvinyl alcohol solution (having a degree of hydrolysis of 88 mol % and a viscosity of 25 mPa*s and proportion of carboxyl groups of 3 mol %) and likewise emulsified with shear and energy input (one minute at 8 000 rpm with a rotor-stator).

[0353] The w/o/w emulsion produced in this way was subsequently further stirred at 400 rpm with an anchor stirrer and kept at room temperature for 10 hours with a nitrogen flow of 100 l/hour.

TABLE-US-00001 TABLE 1 Fillable spherical microparticles using various polymers Mean particle Concentration diameter Pore of pore former D[4,3] Ex. former [% by wt.] Polymer [wt %] [m].sup.1) 1 Ammonium 1.0 Mixture: 70% PBSeT + 257 carbonate 30% P(3HB-co-3HHx).sup.a 2 Ammonium 1.0 Mixture: 70% PBSeT + 378 carbonate 30% P(3HB-co-3HHx).sup.b 3 Ammonium 1.0 Mixture: 30% PBSeT + 195 carbonate 70% P(3HB-co-3HHx).sup.b 4 Ammonium 1.0 Mixture: 30% PBSeT + 96 carbonate 70% P(3HB-co-3HHx).sup.a .sup.aP(3HB-co-3HHx) comprises 7 mol % 3HH; product Aonilex X131A, commercially available from Kaneka;//.sup.bP(3HB-co-3HHx) comprises 11 mol % 3HHx, product Aonilex X151A, commercially available from Kaneka//PBSeT: polybutylene sebacate terephthalate = polyester of 1,4-butanediol and a mixture of sebacic acid and terephthalic acid; product Ecoflex FS Blend A1300 from BASF SE. .sup.1)Determining the particle diameter of the microparticle in the aqueous suspension.

Abbreviations Used

[0354] 3HHx=3-hydroxyhexanoate; 3HB=3-hydroxybutyrate; P(3HB-co-3HHx)=copolyester of 3-hydroxybutyric acid and 3-hydroxyhexanoic acid

Example 5: Procedure for Preparing the Fillable Spherical Microparticles

[0355] Pore former solution: 0.54 g of ammonium carbonate were dissolved in 53.46 g of water (pore former).

[0356] Solution of the aliphatic-aromatic polyester and of the additional polymer: 15.12 g of PBSeT and 6.48 g of polycaprolactone were stirred into 270.0 g of dichloromethane and dissolved at 25 C. while stirring.

[0357] In order to prepare the w/o emulsion, 54.0 g of pore former solution were emulsified in the solution of the aliphatic-aromatic polyester and the additional polymer for 1 minute at 5 000 rpm with a rotor-stator.

[0358] The w/o emulsion thus created was transferred into 419 g of a 0.8% by weight polyvinyl alcohol solution (having a degree of hydrolysis of 88 mol % and a viscosity of 25 mPa*s and proportion of carboxyl groups of 3 mol %) and likewise emulsified with shear and energy input (one minute at 300 rpm with an anchor stirrer).

[0359] The w/o/w emulsion produced in this way was subsequently further stirred at 150 rpm with an anchor stirrer, heated slowly to 40 C. while being stirred, and kept at this temperature for 4 hours with a nitrogen flow of 100 l/hour. Thereafter, the microparticle suspension was cooled to room temperature and filtered.

[0360] The mean particle diameter after filtration was 289 m: water content <0.5%

Example 6

[0361] The procedure was analogous to example 5 with the difference that the polymer mixtures specified in Table 2 (composed of aliphatic-aromatic polyester and a polycaprolactone) were used for the preparation of the fillable spherical microparticles.

Example 7: Procedure for Preparing the Fillable Spherical Microparticles

[0362] The matrix-forming polymer used was a polymer blend of 70% by weight PBSeT and 30% by weight polycaprolactone. The procedure was as follows:

Pore former solution: 0.54 kg of ammonium carbonate was dissolved in 53.5 kg of water (pore former). Solution of the aliphatic-aromatic polyester: 15.1 kg of PBSeT (as in Example 1) and 6.5 kg of polycaprolactone (as in Example 5) were stirred into 270.0 kg of dichloromethane and dissolved at 25 C. while stirring.

[0363] The w/o emulsion was produced by emulsifying the pore former solution in the solution of the aliphatic-aromatic polyester at 170 rpm with a twin-level cross-beam stirrer for 15 minutes.

[0364] The resulting w/o emulsion was transferred into 423 kg of a 0.8% by weight aqueous polyvinyl alcohol solution and likewise emulsified with shear and energy input (one minute at 120 rpm using a round anchor stirrer).

[0365] Stirring of the w/o/w emulsion thus created with an impeller stirrer was then continued at 120 rpm, while reducing the pressure to 800 mbar and gradually increasing the jacket temperature to 40 C. and keeping it at this temperature for 4 hours. Thereafter, the microparticle suspension was cooled to room temperature, filtered and dried at 37 C.

[0366] The average particle diameter D[4,3] determined from the aqueous suspension was 110 m.

TABLE-US-00002 TABLE 2 Fillable spherical microparticles using various polymers Mean particle Concentration diameter Pore of pore former D[4,3] Ex. former [% by wt.] Polymer [wt %] [m].sup.1) 5 Ammonium 1.0 Mixture: 70% PBSeT + 289 carbonate 30% polycaprolactone 6 Ammonium 1.0 Mixture: 30% PBSeT + 277 carbonate 70% polycaprolactone 7 Ammonium 1.0 Mixture: 70% PBSeT + 110 carbonate 30% polycaprolactone PBSeT: polybutylene sebacate terephthalate as in Example 1 Polycaprolactone: commercially available from Perstorp under the trade name Capa 6506. Polycaprolactone having an approximate Mw of 50 000 and a melting point of 58-60 C.

TABLE-US-00003 TABLE 3 Detailled characterization of spherical microparticles using various polymer mixtures. Calculated upper Smallest and lower limits and largest of the pore pore diameter diameter [m] Mean particle measured [m] Lower Upper Number of Ex. diameter [m] Min Max limit.sup.1) limit.sup.2) pores 10 1 257 1.9 11.7 0.05 51.4 Met 2 378 2.1 13.0 0.08 75.6 Met 3 195 1.3 4.8 0.04 39 Met 4 96 0.4 3.4 0.02 19.2 Met 5 289 1.9 7.4 0.06 57.8 Met 6 277 2.5 11.2 0.06 55.4 Met .sup.1) 1/5000 of the mean particle diameter of the microparticles .sup.2) of the mean particle diameter of the microparticles

Examples 8a to 8c: Impregnation of the Spherical Microparticles by Spray Application

[0367] 500 g of the microparticles from Example 7 were initially charged in a ploughshare mixer and sprayed with 1000 g of a solution A at 20 C. by means of a one-phase nozzle having a nozzle diameter of 0.5 mm (spray pressure 2 bar) over 2 min (flow rate 500 ml/min).

Example 8a): Solution a Used was a 10% by Weight Solution of L-Menthol in 1,2-Propylene Glycol

[0368] L-Menthol with a purity of >99.7% is commercially available under the trade name L-Menthol FCC from BASF SE.

Example 8b): Solution a Used was a 10% by Weight Solution of Rose Oxide 90 in 1,2-Propylene Glycol

[0369] Rose oxide 90 (chemical name: tetrahydro-4-methyl-2-(2-methylprop-1-enyl)pyran)) with a purity (sum of isomers, CGC) 98.0% (area), cis-isomer 90.0-95.0% (CGC, area)/trans-isomer 5-10% (CGC, area) is commercially available from BASF SE.

Example 8c): Solution a Used was a 10% by Weight Solution of Dihydrorosan in 1,2-Propylene Glycol

[0370] Dihydrorosan (chemical name tetrahydro-2-isobutyl-4-methyl-2H-pyran) with a purity (sum of isomers, GC)98.0% (area), having a proportion of cis-isomer of 65-85% (area) and trans-isomer of 15-35% (area), commercially available from BASF SE.