METHOD FOR THE CONTROL OF ODOUR

Abstract

The present invention relates to a method for the control of odour by contacting surface-reacted calcium carbonate with odourants, wherein the surface-reacted calcium carbonate is a reaction product of natural ground or precipitated calcium carbonate with carbon dioxide and one or more acids, wherein the carbon dioxide is formed in situ by the acid treatment and/or is supplied from an external source, to the use of the surface-reacted calcium carbonate for the control of odour, as well as to products for the control of odour containing surface reacted calcium carbonate.

Claims

1. Method for the control of odour by contacting surface-reacted calcium carbonate with odourants, wherein the surface-reacted calcium carbonate is a reaction product of natural ground or precipitated calcium carbonate with carbon dioxide and one or more acids in an aqueous medium, wherein the carbon dioxide is formed in situ by the acid treatment and/or is supplied from an external source.

2. Method according to claim 1, characterized in that the natural ground calcium carbonate is selected from calcium carbonate containing minerals selected from the group comprising marble, chalk, dolomite, limestone and mixtures thereof and that the precipitated calcium carbonate is selected from the group comprising precipitated calcium carbonates having aragonitic, vateritic or calcitic mineralogical crystal forms or mixtures thereof.

3. Method according to claim 1, characterized in that the surface-reacted calcium carbonate is in the form of a powder and/or granules, suspension and/or gels, preferably in the form of a powder and/or granules.

4. The process according to claim 1 any one of the preceding claims, characterised in that the surface-reacted calcium carbonate has a specific surface area of from 1 m.sup.2/g to 200 m.sup.2/g, preferably 40 m.sup.2/g to 175 m.sup.2/g, more preferably 50 to 145 m.sup.2/g, especially preferably 60 m.sup.2/g to 90 m.sup.2/g, most preferably 70 m.sup.2/g to 80 m.sup.2/g, measured using nitrogen and the BET method according to ISO 9277.

5. The process according to claim 1, characterised in that the surface-reacted calcium carbonate particles have a volume median grain diameter d.sub.50 of from 0.1 to 50 μm, preferably from 0.5 to 25 μm, more preferably 0.8 to 20 μm, particularly 1 to 10, e.g. 4 to 7 μm.

6. The process according to claim 1, characterized in that the surface-reacted calcium carbonate has an intra-particle intruded specific pore volume within the range of 0.150 to 1.300 cm.sup.3/g, and preferably of 0.178 to 1.244 cm.sup.3/g, calculated from a mercury intrusion porosimetry measurement.

7. The process according to claim 1, characterised in that the surface reacted calcium carbonate is in the form of granules having a volume median granule size of from 0.1-6 mm, preferably from 0.2-5 mm, more preferably from 0.3 to 4 mm, especially preferably from 0.3 to 0.6 mm or 1 mm to 4 mm, most preferably from 0.6 to 1 mm or 1 to 2 mm determined by sieve fractioning.

8. The method according to claim 1, characterized in that the surface reacted calcium carbonate is in the form of granules having a specific surface area of from 1 to 175 m.sup.2/g, preferably of from 2 to 145 m.sup.2/g, more preferably 10 to 100 m.sup.2/g, especially preferably of from 20 to 70 m.sup.2/g, most preferably of from 30 to 40 m.sup.2/g, measured using nitrogen and the BET method according to ISO 9277.

9. Method according to claim 1, characterized in that the odourants are selected from the group comprising odourants contained in human and animal body liquids and secretion such as menses, blood, plasma, sanies, vaginal secretions, mucus, milk, urine, feces, vomit; and perspiration; odourants originating from putrefaction such as of human or animal tissue; food such as dairy products, meat and fish; fruit; textiles; furniture; car interiors; and walling.

10. Method according to claim 1, characterized in that the odourants are selected from the group comprising amines such as triethylamine, diethylamine, trimethylamine, diaminobutane, tetramethylenediamine, pentamethylenediamine, pyridine, indole, 3-methylindole; carboxylic acids such as propionic acid, butanoic acid, 3-methylbutanoic acid, 2-methylpropanoic acid, hexanoic acid; sulphur organic compounds such as thiols, e.g. methanethiol, phosphor organic compounds such as methylphosphine, dimethylphosphine; their derivatives and mixtures thereof.

11. Method according to claim 1, characterized in that the surface reacted calcium carbonate is used in diapers, feminine hygiene products such as pads, panty liners, sanitary napkins and tampons; incontinence products; deodorant formulations; paper towels, bath tissue and facial tissue; nonwoven products such as wipes and medical products; packaging material, preferably plastic, paper or board packaging material, such as wrapping papers, packaging boards; mono and multilayer structures; permeable bags; adsorption pads; paper products, preferably paper sheets, filled and/or coated with surface-reacted calcium carbonate with or without adhesive layer; animal litter; construction and building material; preparations of compost and organic fertilizers.

12. Use of the surface-reacted calcium carbonate as defined in claim 1 for the control of odour, wherein the surface-reacted calcium carbonate is a reaction product of natural ground or precipitated calcium carbonate with carbon dioxide and one or more acids in an aqueous medium, wherein the carbon dioxide is formed in situ by the acid treatment and/or is supplied from an external source.

13. Product for the control of odour, characterized in that it contains surface reacted calcium carbonate as defined in claim 1 for the control of odour, wherein the product is selected from diapers, feminine hygiene products such as pads, panty liners, sanitary napkins and tampons; incontinence products; deodorant formulations; nonwoven products such as wipes and medical products; mono and multilayer structures; permeable bags; adsorption pads; animal litter; construction and building material; preparations of compost and organic fertilizers.

14. (canceled)

Description

DESCRIPTION OF THE FIGURES

[0070] FIG. 1 illustrates the results of ab/adsorption trials of triethylamine using several known ab/adsorbents and surface reacted calcium carbonate powder according to the invention.

[0071] FIG. 2 illustrates the results of ab/adsorption trials of diethylamine and triethylamine using several known ab/adsorbents and surface reacted calcium carbonate granules according to the invention.

[0072] FIG. 3 illustrates the results of ab/adsorption trials of butanoic acid, 3-methylbutanoic acid and hexanoic acid using several known ab/adsorbents and surface reacted calcium carbonate granules according to the invention.

[0073] FIG. 4 illustrates the results of ab/adsorption trials of butanoic acid using several known ab/adsorbents and surface reacted calcium carbonate powders and granules according to the invention.

[0074] FIG. 5 illustrates the results of ab/adsorption trials of butanoic acid using several known ab/adsorbents and surface reacted calcium carbonate powders in dependence of the specific surface areas.

[0075] FIG. 6 illustrates the results of smell intensity evaluation trials of urine in diapers with and without surface reacted calcium carbonate.

[0076] FIG. 7 illustrates the results of hedonic evaluation trials of urine in diapers with and without surface reacted calcium carbonate.

EXAMPLES

1. Measurement Methods

[0077] The following measurement methods were used to evaluate the parameters given in the examples and claims.

BET Specific Surface Area (SSA) of a Material

[0078] The BET specific surface area was measured via the BET process according to ISO 9277 using nitrogen, following conditioning of the sample by heating at 250° C. for a period of 30 minutes. Prior to such measurements, the sample was filtered, rinsed and dried at 110° C. in an oven for at least 12 hours.

Particle Size Distribution (Volume % Particles with a Diameter <X), d.sub.50 Value (Volume Median Grain Diameter) and d.sub.98 Value of a Particulate Material:

[0079] Volume median grain diameter d.sub.50 was evaluated using a Malvern Mastersizer 2000 Laser Diffraction System. The d.sub.50 or d.sub.98 value, measured using a Malvern Mastersizer 2000 Laser Diffraction System, indicates a diameter value such that 50% or 98% by volume, respectively, of the particles have a diameter of less than this value. The raw data obtained by the measurement are analysed using the Mie theory, with a particle refractive index of 1.57 and an absorption index of 0.005.

[0080] The weight median grain diameter is determined by the sedimentation method, which is an analysis of sedimentation behaviour in a gravimetric field. The measurement is made with a Sedigraph™ 5100, Micromeritics Instrument Corporation. The method and the instrument are known to the skilled person and are commonly used to determine grain size of fillers and pigments. The measurement is carried out in an aqueous solution of 0.1 wt % Na.sub.4P.sub.2O.sub.7. The samples were dispersed using a high speed stirrer and supersonicated.

[0081] The processes and instruments are known to the skilled person and are commonly used to determine grain size of fillers and pigments.

Porosity/Pore Volume

[0082] The porosity or pore volume is measured using a Micromeritics Autopore IV 9500 mercury porosimeter having a maximum applied pressure of mercury 414 MPa (60 000 psi), equivalent to a Laplace throat diameter of 0.004 μm (˜nm). The equilibration time used at each pressure step is 20 seconds. The sample material is sealed in a 5 ml chamber powder penetrometer for analysis. The data are corrected for mercury compression, penetrometer expansion and sample material compression using the software Pore-Comp (Gane, P. A. C., Kettle, J. P., Matthews, G. P. and Ridgway, C. J., “Void Space Structure of Compressible Polymer Spheres and Consolidated Calcium Carbonate Paper-Coating Formulations”, Industrial and Engineering Chemistry Research, 35(5), 1996, p 1753-1764.).

2. Material and Equipment

2.1. Equipment

[0083] Sorption tube (Sigma Aldrich, stainless steel, ¼ in×3½ in) [0084] Thermal desorption tube with Tenax® TA (Sigma Aldrich, stainless steel, ¼ in×3½ in) [0085] Pocket Pump 210-1000 series (of SKC Inc., Eighty Four, PA, USA) [0086] TD-GC-MS (thermal desorption-gas chromotograph-mass spectrometer):

[0087] TD TurboMatrix Perkin Elmer [0088] Temperature Mode: Tube 300° C., Valve 195° C., Transfer 200° C., Trap Low−20° C., Trap High 300° C. [0089] Timing: Desorb 10 min, Purge 1.0 min, Trap Hold 5.0 min [0090] Pneumatic Settings: Column 95 kPa, Outlet Split 50 ml/min, Inlet Split 40 ml/min, Desorb 30 mL/min

[0091] GC Method AutoSystem XL Perkin Elmer [0092] Column: Optima 5 Accent 1.0 μm, 60 m*0.32 mm, Macherey-Nagel [0093] Temperature of oven: 110° C. for 15 min (amines) [0094] Temperature of oven: 130° C. for 10 min (acids) [0095] MS Turbo Mass Perkin Elmer [0096] Solvent Delay 0.0 min [0097] Full Scan 25 to 350 m/z (mass/charge) (EI+)

2.2. Material

Absorbents

[0098] Millicarb OG (Omya AG; natural ground calcium carbonate; d.sub.50=3 μm) [0099] Kaolin clay (Sigma-Aldrich; CAS 1332-58-7) [0100] Sea sand (silica) (CAS 60676-86-0) [0101] Vermiculite (BET specific surface area: 4.3 m.sup.2/g) [0102] Diatomite (BET specific surface area: 5.6 m.sup.2/g) [0103] Activated Carbon (BET specific surface area: 1400 m.sup.2/g)

[0104] Surface-Reacted Calcium Carbonate (SRCC) Powder 1

[0105] (d.sub.50=4.3 μm, d.sub.98=8.6 μm, SSA=51.6 m.sup.2g.sup.−1)

[0106] SRCC 1 was obtained by preparing 8 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 20 wt %, based on the total weight of the aqueous suspension, is obtained. Whilst mixing the slurry, 1.22 kg of an aqueous solution containing 30 wt % phosphoric acid and 0.4% aluminium sulphate hexadecahydrate was added to said suspension over a period of 10 minutes at a temperature of 70° C. After the addition of the solution, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0107] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 1 is 0.644 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.26 μm).

[0108] Surface-Reacted Calcium Carbonate (SRCC) Powder 2

[0109] (d.sub.50=3.7 μm, d.sub.98=8.1 μm, SSA=72.7 m.sup.2g.sup.−1)

[0110] SRCC 2 was obtained by preparing 8 litres of an aqueous suspension of wet ground calcium carbonate, containing polyacrylate dispersant added in the grinding process, in a mixing vessel by adjusting the solids content of a ground marble calcium carbonate from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 20 wt %, based on the total weight of the aqueous suspension, is obtained.

[0111] Whilst mixing the slurry, 1.2 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. Simultaneous to the start of the phosphoric acid solution addition, 0.92 kg of an aqueous solution containing 10 wt % sodium silicate was added to said suspension over a period of 14 minutes. After the addition of the two solutions, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0112] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 2 is 0.491 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.14 μm).

[0113] Surface-Reacted Calcium Carbonate (SRCC) Powder 3

[0114] (d.sub.50=3.5 μm, d.sub.98=7.6 μm, SSA=92.3 m.sup.2g.sup.−1)

[0115] SRCC 3 was obtained by preparing 8 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 20 wt %, based on the total weight of the aqueous suspension, is obtained.

[0116] Whilst mixing the slurry, 1.2 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. Two minutes after the start of the phosphoric acid solution addition, 0.37 kg of an aqueous solution containing 25 wt % citric acid was added to said suspension over a period of 0.5 minutes. After the addition of the two solutions, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0117] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 3 is 0.258 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.09 μm).

[0118] Surface-Reacted Calcium Carbonate (SRCC) Powder 4

[0119] (d.sub.50=5.5 μm, d.sub.98=10.6 μm, SSA=141.5 m.sup.2g.sup.−1)

[0120] SRCC 4 was obtained by preparing 10 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 16 wt %, based on the total weight of the aqueous suspension, is obtained.

[0121] Whilst mixing the slurry, 3 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. Two minutes after the start of the phosphoric acid solution addition, 0.36 kg of an aqueous solution containing 25 wt % citric acid was added to said suspension over a period of 0.5 minutes. After the addition of the two solutions, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0122] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 4 is 1.025 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.33 μm).

[0123] Surface-Reacted Calcium Carbonate (SRCC) Powder 5

[0124] (d.sub.50=5.1 μm, d.sub.98=9.8 μm, SSA=51.4 m.sup.2g.sup.−1)

[0125] SRCC 5 was obtained by preparing 10 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 15 wt %, based on the total weight of the aqueous suspension, is obtained.

[0126] Whilst mixing the slurry, 1.7 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. After the addition of the solution, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0127] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 5 is 1.154 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.51 μm).

[0128] Surface-Reacted Calcium Carbonate (SRCC) Powder 6

[0129] (d.sub.50=5.0 μm, d.sub.98=9.6 μm, SSA=62.2 m.sup.2g.sup.−1)

[0130] SRCC 6 was obtained by preparing 10 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 15 wt %, based on the total weight of the aqueous suspension, is obtained.

[0131] Whilst mixing the slurry, 1.7 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. Four minutes after starting the addition of phosphoric acid solution, 41 g of an aqueous solution containing trisodium citrate was added in a separate stream to the slurry over a period of 0.5 minutes. After the addition of the solution, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0132] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 6 is 1.086 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.41 μm).

[0133] Surface-Reacted Calcium Carbonate (SRCC) Powder 7

[0134] (d.sub.50=5.1 μm, d.sub.98=9.8 μm, SSA=77.1 m.sup.2g.sup.−1)

[0135] SRCC 7 was obtained by preparing 10 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 15 wt %, based on the total weight of the aqueous suspension, is obtained.

[0136] Whilst mixing the slurry, 1.7 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. Simultaneous to the start of the phosphoric acid solution addition, 0.88 kg of an aqueous solution containing 7.5 wt % sodium silicate was added to said suspension over a period of 10 minutes. After the addition of the two solutions, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0137] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 7 is 1.108 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.41 μm).

[0138] Surface-Reacted Calcium Carbonate (SRCC) Powder 8

[0139] (d.sub.50=4.4 μm, d.sub.98=8.6 μm, SSA=39.9 m.sup.2g.sup.−1)

[0140] SRCC 8 was obtained by preparing 10 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing polyacrylate dispersant added in the grinding process, from Omya Hustadmarmor AS having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 15 wt %, based on the total weight of the aqueous suspension, is obtained.

[0141] Whilst mixing the slurry, 0.83 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. After the addition of the solution, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0142] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 8 is 0.412 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.17 μm).

[0143] Surface-Reacted Calcium Carbonate Granules 1

[0144] As a starting material for granulation the following surface-reacted calcium carbonate powder SRCC 9 (d.sub.50=6.6 μm, d.sub.98=13.7 μm, SSA=59.9 m.sup.2g.sup.−1) was prepared:

[0145] 350 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel was prepared by adjusting the solids content of a wet ground limestone calcium carbonate, containing dispersant added in the grinding process from Omya SAS, Orgon, having a mass based median particle size of 1.3 μm, as determined by sedimentation, such that a solids content of 10 wt %, based on the total weight of the aqueous suspension, is obtained.

[0146] Whilst mixing the slurry at a speed of 6.2 m/s, 11.2 kg phosphoric acid was added in form of an aqueous solution containing 30 wt % phosphoric acid to said suspension over a period of 20 minutes at a temperature of 70° C. After the addition of the acid, the slurry was stirred for additional 5 minutes, before removing it from the vessel and drying using a j et-dryer.

[0147] The intra-particle intruded specific pore volume of this surface-reacted calcium carbonate is 0.939 cm.sup.3/g (for the pore diameter range of 0.004 to 0.51 μm).

[0148] 400 g of this surface-reacted calcium carbonate was added to a Lodige mixer (Model L5, 5 liter, Gebr. Lodige Maschinenbau GmbH, Paderborn, Germany). Subsequently, 400 g of a solution containing 3 wt % sodium carboxymethylcellulose (Sigma Aldrich (average molar mass 90000 g/mol; CAS No. 9004-32-4) in water was added using a spray bottle while mixing the powder with both the blending element (speed varied between 500 rpm and the maximum speed (999 rpm), mainly between 700-999 rpm) and the cutter until the material started to look a little clumpy. After this point, the sample turned into a paste. This was again rectified via the addition of 100 g of dry surface-reacted calcium carbonate. The sample was mixed a few more minutes until individual granules were formed. Subsequently, the sample was removed and dried at 90° C. for 12 hours.

[0149] Surface-Reacted Calcium Carbonate Granules 2 and 3

[0150] 530 g of SRCC 9 powder were saturated with water providing a solids content of 61 wt % and added to the Lodige mixer. Subsequently, 26 g sodium carboxymethylcellulose (Sigma Aldrich (average molar mass 90000 g/mol; CAS No. 9004-32-4) was added, dry, and the combination was mixed for several minutes to ensure proper blending. Subsequently, using a spray bottle, tap water was added over time, while mixing the powder with both the blending element (speed varied between 500 rpm and the maximum speed (999 rpm), mainly between 700-999 rpm) and the cutter until the material started to look a little clumpy. At this point, a little more water was then added and the sample turned to a paste. This was again rectified via the addition of 100 g dry surface-reacted calcium carbonate. The sample was mixed a few more minutes until individual granules were formed. The final solids of this sample was 65 wt %. Subsequently, the sample was removed and dried at 90° C. for 12 hours.

[0151] The dried sample was sieved on a Retsch sieve into separate size fractions, namely <0.3 mm, between 0.3 and 0.6 mm, between 0.6 and 1 mm, and between 1 and 2 mm.

[0152] For further trials the following fractions were used, where x is the particle size of the granules:

Surface reacted calcium carbonate granules 2: 0.6 mm<x<1 mm
Surface reacted calcium carbonate granules 3: 0.3 mm<x<0.6 mm

Odourants

[0153] Diethylamine (Sigma Aldrich, CAS 109-89-7) [0154] Triethylamine (Sigma Aldrich, CAS 121-44-8) [0155] Butanoic acid (Sigma Aldrich, CAS 107-92-6) [0156] 3-Methylbutanoic acid (Sigma Aldrich, CAS 503-74-25) [0157] Hexanoic acid (Sigma Aldrich, CAS 142-62-1)

3. Ab/Adsorption Trials

3.1. Surface Reacted Calcium Carbonate Powders

[0158] A stock solution of 1500 mg/l triethylamine in water was prepared.

[0159] For carrying out the ab/adsorption trials the ab/adsorption tube was filled with: [0160] Example 1: No ab/adsorbent [0161] Example 2: 0.4 g of a mixture of 1 g sea sand and 0.5 g Millicarb OG [0162] Examples 3-6: 0.4 g of a mixture of 1 g sea sand and 0.5 g SRCC powders 1 to 4, respectively

[0163] In front of the sorption tube, a vial filled with 10 μl of the prepared triethylamine based stock solution was installed, behind the tube a thermal desorption tube with a Tenax TA.

[0164] During 5 min. air was sucked from the odourant filled vial through both of the tubes by means of a pocket pump (SKC) at a rate of 80 ml/min at room temperature (23° C.). Subsequently, the odourant content in the Tenax TA tube was analysed by means of TD-GC-MS.

[0165] The area under the detected peak proportionally corresponds to the odourant concentration. Therefore, odourant ab/adsorption by different materials can be compared by means of the peak area.

[0166] The trials were repeated several times. The average values obtained are summarized in FIG. 1 reflecting the resulting relative ab/adsorption capacity of the respective samples, wherein 100% refers to the maximum value determined for the blank sample (Example 1).

[0167] As can be clearly seen from these results, there is only a very poor ab/adsorption of triethylamine by conventional natural ground calcium carbonate (Millicarb OG). The result, however, looks quite different using powders of surface-reacted calcium carbonate, showing much higher levels of sorption.

[0168] Based on these findings further experiments were carried out using further odourants and surface reacted calcium carbonate granules.

3.2. Surface Reacted Calcium Carbonate Granules

[0169] The following stock solutions were prepared having the respective given concentrations in water:

Diethylamine: 3000 mg/l
Triethylamine: 1500 mg/l
Butanoic acid: 1000 mg/l
3-Methylbutanoic acid: 1000 mg/l
Hexanoic acid: 1600 mg/l

[0170] For carrying out the ab/adsorption trials the sorption tube was filled with: [0171] Example 7: No ab/adsorbent [0172] Example 8: 0.4 g of a mixture of 1 g sea sand and 0.5 g Millicarb OG [0173] Example 9: 0.4 g of a mixture of 1 g sea sand and 0.5 g kaolin clay [0174] Example 10: 0.4 g surface reacted calcium carbonate granules 1

[0175] In front of the absorption tube, a vial filled with 10 μl of the respective stock solution was installed, behind the tube a thermal desorption tube with a Tenax TA.

[0176] During 5 min. air was sucked from the odourant filled vial through both of the tubes by means of a pocket pump (SKC) at a rate of 80 ml/min at room temperature (23° C.). Subsequently, the odourant content in the Tenax TA tube was analyzed by means of TD-GC-MS.

[0177] The area under the detected peak proportionally corresponds to the odourant concentration. Therefore, odourant ab/adsorption by different materials can be compared by means of the peak area.

[0178] The trials were repeated several times. The average values obtained are summarized in FIGS. 2 and 3 reflecting the resulting relative absorption capacity of the respective samples, wherein 100% refers to the maximum value determined for the blank sample (Example 7).

[0179] As can be clearly observed from these results, there is only a very poor ab/adsorption of diethylamine and triethylamine by conventional natural ground calcium carbonate (Millicarb OG). Contrary to this, these odourants are essentially completely ab/adsorbed by the surface reacted calcium carbonate granules.

[0180] As regards butanoic acid, 3-methylbutanoic acid and hexanoic acid, which are quite well adsorbed by kaolin clay, these results can even be improved by using surface reacted calcium carbonate granules.

[0181] Furthermore, contrary to, e.g. natural ground calcium carbonate or kaolin clay, surface reacted calcium carbonate granules 1 are able to ab/adsorb odourants of different chemical classes equally well.

[0182] Apart from these quantitative results, an olfactory test was carried out, wherein it turned out that the sample of surface reacted calcium carbonate granules having butanoic acid, 3-methylbutanoic acid, and hexanoic acid absorbed into or adsorbed on it did not have any smell, whereas the sample kaolin clay had an unpleasant smell.

[0183] This finding led to further olfactory tests described further below.

3.3. Further Butanoic Acid Ab/Adsorption Trials

[0184] As butanoic acid is one of the most unpleasant odours in the food sector, further evaluations were made regarding this odourant.

[0185] A stock solution of butanoic acid was prepared having a concentration in water of 5 wt %.

[0186] For carrying out the sorption trials the sorption tube was filled with: [0187] Example 11: No ab/adsorbent [0188] Example 12: Silica gel [0189] Example 13: Vermiculite [0190] Example 14: Diatomite [0191] Example 15: Activated Carbon [0192] Example 16: Kaolin clay [0193] Example 17: Millicarb OG [0194] Example 18-21: SRCC powders 5 to 8, respectively [0195] Examples 22+23: Surface reacted calcium carbonate (SRCC) granules 2 and 3, respectively

[0196] 0.2000 g of glass wadding and 0.8000 g of the respective ab/adsorbent (except for the granules, which were used alone) were weighed into a beaker. The mixture was cut with scissors until a homogeneous mixture was obtained. 60 mg of the absorbent/glass wadding mixture, or 48 mg of SRCC granules 2 or 3, respectively, were filled into the sorption tube. In front of the sorption tube, a vial filled with 10 μl of the butanoic acid stock solution was installed, behind the tube a thermal desorption tube with a Tenax TA. After the solution was filled with the stock solution, it was heated in a water bath at 40° C. Subsequently, during 5 min. air was sucked from the odourant filled vial through both of the tubes by means of a pocket pump (SKC) at a rate of 80 ml/min at 40° C. Subsequently, the odourant content in the Tenax TA tube was analysed by means of TD-GC-MS.

[0197] The area under the detected peak proportionally corresponds to the odourant concentration. Therefore, odourant ab/adsorption by different materials can be compared by means of the peak area.

[0198] The trials were repeated several times. The average values obtained are summarized in FIG. 4 reflecting the resulting relative ab/adsorption capacity of the respective samples, wherein 100% refers to the maximum value determined for the blank sample (Example 11).

[0199] As can be seen from FIG. 4 the sorption capacity of any one of the SRCC powders and granules is significantly better than conventional natural ground calcium carbonate as well as vermiculite, diatomite and kaolin clay.

[0200] As regards silica gel and activated carbon, the surface reacted calcium carbonate powders provide at least comparable values, wherein it has to be noted that silica gel as well as activated carbon have a considerably higher specific surface area, such that the sorption capacity per surface area is significantly higher than the one of silica gel and activated carbon (cf. FIG. 5).

4. Olfactory Trials

[0201] In the following trials comparative human sensory measurements of the smell of urine in an incontinence product were carried out. For this purpose products with and without the surface reacted calcium carbonate according to the invention were compared as regards the parameters of smell intensity (strong smell/no smell) and hedonic evaluation (pleasant/unpleasant).

4.1. Measurement Methods

[0202] Smell may be described by several smell parameters. The determination of these parameters is described in different guidelines, the following of which were used: [0203] Intensity (VDI 3882; Olfactometry; determination of odour intensity; technical Rule, [0204] Publication date: October 1992; Beuth Verlag) [0205] Hedonic smell impression (VDI 3882 and ISO 16000-28)

[0206] The smell measurements were performed by 12 test persons and one supervisor. The testing team was trained and selected according to DIN EN 13725:2003 [1].

4.1.1. Smell Intensity

[0207] The evaluation of the intensity is carried out by means of a category scale from “not perceptible” (0) to “extremely strong” (6) according to VDI 3882.

[0208] For evaluating the smell intensity the test person assigned his smell impression to the following terms given in table 1:

TABLE-US-00001 TABLE 1 Smell Intensity category scale Extremely strong 6 Very strong 5 Strong 4 Considerable 3 Weak 2 Very weak 1 Not perceptible 0

[0209] In this respect, level 1 is assigned if the odour detection threshold is exceeded, which means that the test person was sure that a smell was noticed, even if it could not be clearly assigned to a certain smell quality.

[0210] Subsequently, the arithmetic average of the respective individual evaluations of the group of test persons was calculated.

4.1.2. Hedonic Smell Impression

[0211] The hedonic evaluation describes whether a smell impression was a pleasant or unpleasant sensation. For evaluating the hedonic smell impression, the following smell scale was used:

[0212] Subsequently, the arithmetic average of the respective individual evaluations of the group of test persons was calculated.

4.2. Experimental Procedure

4.2.1 Material

[0213] The following material was used: [0214] 2 cloth diapers (100% cotton; Alana; available from dm-drogerie markt GmbH+Co. KG) [0215] Nalophan PET odour sample bags (available from Odournet GmbH) [0216] PureSniff device (available from Odournet GmbH) [0217] 20 g of surface-reacted calcium carbonate (SRCC) powder 10 (d.sub.50=6.1 μm, d.sub.98=14.2 μm, SSA=144.0 m.sup.2g.sup.−1)

[0218] SRCC 10 was obtained by preparing 350 litres of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting the solids content of a wet ground marble calcium carbonate, containing dispersant added in the grinding process, from Omya Avenza SPA having a mass based particle size distribution with 90 w/w % of the particles finer than 2 μm, as determined by sedimentation, such that a solids content of 16 wt %, based on the total weight of the aqueous suspension, is obtained. Whilst mixing the slurry, 104 kg of an aqueous solution containing 30 wt % phosphoric acid was added to said suspension over a period of 10 minutes at a temperature of 70° C. Two minutes after the start of the phosphoric acid solution addition, 12.5 kg of an aqueous solution containing 25 wt % citric acid was added to said suspension over a period of 0.5 minutes.

[0219] After the addition of the two solutions, the slurry was stirred for an additional 5 minutes, before removing it from the vessel and drying.

[0220] The intra-particle intruded specific pore volume of surface-reacted calcium carbonate powder 10 is 0.856 g/cm.sup.3 (for the pore diameter range of 0.004 to 0.33 μm). [0221] A mixture of urine (including first morning urine) of three probands

4.2.2 Sample Preparation

[0222] A diaper was folded once, and 20 g of surface reacted calcium carbonate was poured onto it. The diaper was folded again to cover the surface reacted calcium carbonate. A second diaper was folded likewise without containing surface reacted calcium carbonate. For simulating the urination, the diapers were each placed into a Nalophan bag having a volume of 601, and 10 ml of urine was emptied onto each of the diapers. Further simulated urinations were performed after 2 hours (10 ml) and 4 hours (5 ml). The bags were filled up with air and stored in a climate chamber at 36° C.

[0223] Smell samples were taken after 1 min, 1 h, 2 h, 3 h, 4 h, 6 h and 8 h.

4.2.3 Sample Evaluation

[0224] After taking a sample, the sample was transferred into a PureSniff device generating a constant and highly repeatable odour sample volume flow at the outlet (nose mask) of the device. In this way, each olfactory test person receives an identical sample with a standardized volume flow over a constant presentation time, ensuring repeatable conditions for the odour evaluation. At any time, each sample was evaluated by each test person twice in randomized order. Thus, in total each sample was evaluated (N=) 24 times at any time of sample taking.

4.3. Results

[0225] The total average values of the intensity evaluation are summarized in table 2 and illustrated in FIG. 6:

TABLE-US-00002 TABLE 2 No surface reacted 20 g surface reacted calcium carbonate calcium carbonate N = 24 (comparative) (inventive) 1 min 1.52 1.25 1 h 3.00 2.13 2 h 3.05 2.18 3 h 2.85 2.28 4 h 2.69 2.22 6 h 2.88 2.65 8 h 3.17 2.61

[0226] The total average values of the hedonic evaluation are summarized in table 3 and illustrated in FIG. 7:

TABLE-US-00003 TABLE 3 No surface reacted 20 g surface reacted calcium carbonate calcium carbonate N = 24 (comparative) (inventive) 1 min −0.73 −0.73 1 h −1.78 −1.20 2 h −1.73 −1.33 3 h −1.73 −1.35 4 h −1.89 −1.53 6 h −1.95 −1.73 8 h −2.14 −1.75

[0227] These results very clearly show that the use of surface reacted calcium carbonate in diapers containing urine, not only provide a reduction of the smell intensity, but also an improvement of the hedonic impression.