PREPARATION OF LOW-DUSTING OR NON-DUSTING WATERDISPERSIBLE CROSSLINKED POLYVINYLPYRROLIDONE GRANULES

Abstract

Preparation of low-dusting or dust-free waterdispersible crosslinked polyvinylpyrrolidone (PVPP) granules characterized by extruding a dough consisting of said PVPP and water through a die plate and subsequent drying of the granules.

Claims

1. A method of preparing low-dusting or non-dusting granules consisting of PVPP comprising extruding a dough consisting of said PVPP and water through a die plate and subsequent drying of the granules.

2. The method according to claim 1 having a residual humidity after drying of from 10 to 2 wt-%.

3. The method according to claim 1 having a dust number after drying of the granules of between 70 and 0.

4. The method according to claim 3 having a dust number after drying of between 65 and 0.

5. The method according to claim 4 having a dust number after drying of between 52 and 0.

6. The method according to claim 5 having a dust number after drying of between 10 and 0.

7. The method according to claim 1 wherein granules of 500 μm diameter and higher make up 75% or more of said preparation.

8. The method according to claim 7 wherein granules of 500 μm diameter and higher make up 95% or more of said preparation.

9. The method according to claim 7 wherein granules of 850 μm diameter and higher make up 10% or less of said preparation.

10. A method for producing low-dusting or non-dusting granules consisting of PVPP, comprising extruding a dough consisting of said PVPP and water, said dough having a water content of between 25 and 75 wt-% through a die plate, and subsequent drying of the granules.

11. The method according to claim 10 for producing low-dusting or non-dusting granules consisting of PVPP, comprising extruding a dough consisting of said PVPP and water, said dough having a water content of between 30 and 70 wt-% through a die plate, and subsequent drying of the granules.

12. The method according to claim 11 for producing low-dusting or non-dusting granules consisting of PVPP, comprising extruding a dough consisting of said PVPP and water, said dough having a water content of between 40 and 65 wt-% through a die plate, and subsequent drying of the granules.

13. The method according to claim 12 for producing low-dusting or non-dusting granules consisting of PVPP, comprising extruding a dough consisting of said PVPP and water, said dough having a water content of between 45 and 65 wt-% through a die plate, and subsequent drying of the granules.

14. The method according to claim 10, comprising extruding the dough consisting of said PVPP and water without additional heating.

15. A method of treating a beverage comprising (i) contacting the beverage with PVPP granules prepared according to claim 1, and (ii) subsequently filtering, settling, and/or centrifuging the beverage to remove the PVPP.

Description

EXAMPLES

Example 1

[0015] Crosslinked PVPP as fine powder (Divergan F) and water are mixed thoroughly in a standard Lödige mixer (Lödige ploughshare mixer M5 RMK, speed set to 160 rpm with chopper, produced by Gebrüder Lödige Maschinenbau GmbH) in a weight-ratio of 35 to 65. The resulting dough is extruded at room temperature (20° C., 1013.25 mbar) in a dome extruder (DomeGranulator DG-L1, produced by Fuji Paudal Co.) through a die plate with a hole diameter of 0.7 mm at an extruder speed of 50 rpm. This results in strings that break into single granules directly, by falling down and/or slight mechanical agitation. The granules are then put into a polypropylene box and transferred into a standard lab oven operated at 50° C. After drying overnight, the granules consisted of at least 90% crosslinked PVPP. The granules are free-flowing and show nearly no dusting (dust number 13.8). Upon adding the granules to water at a concentration of 50 g per hL they quickly disintegrate into a fine suspension of PVPP particles in water. The granules show a catechin absorption of 67.6% whereas the ungranulated PVPP employed to make the granules show a catechin absorption of 67.0%.

Example 2a

[0016] As example 1, but an extruder speed of 40 rpm was used and the drying did take place in a fluidized bed (Fluidizd bed Aeromatic Strea 1 by Aeromatic AG) operated at an air temperature of 50° C. The resulting granules were nearly non-dusting (dust number 10.6), free-flowing and very quickly disintegrated upon addition to water.

Example 2b

[0017] As example 2a, but an extruder speed of 60 rpm was used. The resulting granules did not show differences compared to granules from Example 2a (dust number 13.4).

Example 2c

[0018] As example 2a, but an extruder speed of 80 rpm was used. The resulting granules did not show differences compared to granules from Example 2a (dust number 6.4).

Example 3a (not According to the Invention)

[0019] A ratio of PVPP to water of 80 to 20 was used. Otherwise, the same process as in example 1 but with an extruder speed of 40 rpm was employed. Granules with a significant number of fines (dust number 142) before a sieving step were obtained, the granules also break easily. The particle size distribution of the granules is displayed in Table 2.

Example 3b

[0020] As example 3a, but with a ratio of PVPP to water of 75 to 25. The resulting granules show significant less fines and break less easily. The particle size distribution of the granules is displayed in Table 2.

Example 3c

[0021] As example 3a, but with a ratio of PVPP to water of 70 to 30. The resulting granules do not dust much (dust number 64) and are stable. The particle size distribution of the granules is displayed in Table 2.

Example 3d

[0022] As example 3a, but with a ratio of PVPP to water of 60 to 40. The resulting granules do not dust much (dust number 52) and are stable. The particle size distribution of the granules is displayed in Table 2.

Example 3e

[0023] As example 3a, but with a ratio of PVPP to water of 50 to 50. The resulting granules do not dust (dust number 8.5) and are stable. The particle size distribution of the granules is displayed in Table 2.

Example 3f

[0024] As example 3a, but with a ratio of PVPP to water of 65 to 35. The resulting granules do not dust (dust number 3.04) and are stable. The particle size distribution of the granules is displayed in Table 2.

EXAMPLES NOT ACCORDING TO INVENTION

Example 4

[0025] As example 3a, but with a ratio of PVPP to water of 100 to 0. No granules are obtained but rather the originally used PVPP powder.

Example 5

[0026] As example 3a, but with a ratio of PVPP to water of 20 to 80. The resulting dough cannot be extruded as it is too wet.

[0027] The results of examples 1 to 5 are reported in Table 1

TABLE-US-00001 TABLE 1 PVPP Water Dust Catechin Extruder Example (wt-%) (wt-%) value abs speed 1 35 65 13.8 67.6 50 2a 35 65 10.6 40 2b 35 65 13.4 60 2c 35 65 6.4 80 3a (not 80 20 142 40 according to the invention) 3b 75 25 40 3c 70 30 64 40 3d 60 40 52 40 3e 50 50 8.5 40 3f 35 65 3.04 40 4 (not 100 0 No granules 40 according to formed the invention) 5 (not 20 80 Too wet, not according to extrudable the invention)

Analytical Tools:

[0028] Humidity measurements: Residual humidity was measured on a Mettler Toledo halogen dryer HR 73 by placing 1 g of a sample on the balance and dry it at 130° C. to until the mass changed less than 1 mg in cos.

[0029] Sieve analysis: For particle size distribution, a sieve analysis was carried out by placing 25 g of a sample on a Retsch vibration sieve machine AS 200 control g using sieves with a diameter of 200 mm. Subsequently, the sieves were vibrated for 10 minutes at an amplitude of 2.0 mm. For analysis, the sieves were weighted before and after vibration.

[0030] The results of the sieve analysis are reported in Table 2.

TABLE-US-00002 TABLE 2 Example 3a (not according to the invention) Example 3b Example 3c Example 3d Example 3e Example 3f Water in 20.0% 25.0%  30.0%   40.0%   50.0%   65.0%   dough >1000 μm  1.1% .sup. 0% 0% 0% 0% 3.5%.sup.  >850 μm 1.9% 1.4% 0% 1.5%.sup.  0% 1% >710 μm 26.5%  41% 52.2%   32.7%   16.5%   33.3%   >600 μm 22.6% 30.2%  36.9%   53%  73.8%   51.2%   >500 μm 18.4% 15.9%  9.6%.sup.  11.9%   9.1%.sup.  10.4%   >425 μm 10.9% 7.2% 1.3%.sup.  0.8%.sup.  0.7%.sup.  0.5%.sup.  >250 μm 7.0% 3.4% 3.3%.sup.  0% 0% 0% >180 μm 2.9% 1.0% 0% 0% 0% 0%  >63 μm 8.0% .sup. 0% 0% 0% 0% 0%  >0 μm 0.5% .sup. 0% 0% 0% 0% 0%

[0031] Catechin absorption: A beer model system, which contains the phenolic compound (+)-catechin in a 5% ethanol solution, is used as a relative measure of the absorptive capacity of the PPVP. The absorbance is measured at 280 nm against a solvent blank.

[0032] As reagents, absolute ethanol (DAB quality), dried (+)-catechin hydrate (e.g. Fluka, prod. no. 22110, drying process for catechin hydrate: 12 h in a vacuum dryer at 60° C. with subsequent determination of dry matter stored in a desiccator), ultrapure water, HPLC quality (Millipore treatment equipment) were employed. For the catechin solution 80 mg (based on dry matter) were transferred with 50 mL of ethanol into a 1 L volumetric flask, dissolved by heavy mixing, filled up with ultrapure water to the calibration mark and mix again. For the ethanol solution, 50 mL of ethanol were filled in a 1 L volumetric flask and filled up with ultrapure water to the calibration mark.

[0033] In all cases the dry matter of Divergan is determined for an exact calculation of the PVPP quantity, which is needed for the analysis. 50 mg of dry PVPP were weighted in a 150 mL beaker to form the blank. Subsequently, 100 mL ethanol solution were added into the beaker with the blank for a contact time of exactly five minutes. The suspension is filtered immediately through a glass filter type G3 (pore size 16-40 μm), or, for very fine PVPP a glass filter type G4 (pore size 10-16 μm) and measured against the 5% ethanol solution at 280 nm (EBL). To form the sample, 50 mg—under account of the dry matter—of the PVPP sample were weighted into a second beaker. Subsequently, 100 mL catechin solution were added to the sample and proceeded in the same way as with the blank sample (ESA). The “untreated” catechin solution was measured against the 5% ethanol solution at 280 nm. This value is referred to the basic content E100.

[0034] All solutions were measured in a 1 cm quartz cuvette in a standard UV-Vis spectrometer at 280 nm. The catechin adsorption is calculated by:

[00001]$\mathrm{Catechin}\mathrm{adsorption}\mathrm{in}\%=\frac{\left(E100-\left(\mathrm{ESA}-\mathrm{EBL}\right)\right)}{E100}\times 100\%$

E100: extinction of the catechin solution
ESA: extinction of the sample
EBL: extinction of the blank

Determination of Powder Flow Properties

[0035] Various glass funnels with a height of 90 mm, a slope angel of 30° and openings of 48 mm on the upper and 2.5, 5, 8, 12 and 18 mm on the lower end were filled to the brim with a representative sample of a given product while keeping the lower opening hole closed. Upon opening, the products flow out of the funnel. If the product does not flow, the next funnel with the next larger opening is taken and the procedure is repeated until one has identified the funnel the product flows through. Sample with very high flowability flow through the 2.5 mm funnel, samples with very bad flowability do not flow through the 18 mm funnel.

TABLE-US-00003 Example Funnel Divergan F 18 mm  (ungranulated PVPP) 3a 8 mm 3c 8 mm 3f 8 mm 1 8 mm