PROCESS FOR THE PREPARATION OF CRUMBLES COMPRISING CALCIUM CARBONATE

Abstract

The present invention relates to crumbles comprising at least one calcium carbonate-containing material, a process for the preparation of the crumbles, an article comprising the crumbles as well as an use of the crumbles in paper making, paper coating, food, plastic, preferably films, more preferably blown films or breathable films, fibres, polyvinyl chloride, plastisols, thermosetting polymers, more preferably thermosetting unsaturated polyesters or thermosetting unsaturated polyurethanes, agricultural, paint, coatings, adhesives, sealants, pharmaceuticals, agricultural, construction and/or cosmetic applications.

Claims

1. Crumbles comprising at least one calcium carbonate-containing material, the crumbles a) having solids content of 78.0 wt.-% to 90.0 wt.-%, based on the total weight of the crumbles, b) comprising particles of the at least one calcium carbonate-containing material having a i) weight particle size d.sub.75 of 0.7 to 3.0 m, ii) weight median particle size d.sub.50 of 0.5 to 2.0 m, iii) weight particle size d.sub.25 of 0.1 to 1.0 m, as measured according to the sedimentation method, and c) comprising particles of the at least one calcium carbonate-containing material having a BET specific surface area of from 4.0 to 12.0 m.sup.2/g, measured by nitrogen gas adsorption using the BET isotherm (ISO 9277:2010).

2. The crumbles according to claim 1, wherein the at least one calcium carbonate-containing material is at least one natural calcium carbonate-containing material, preferably dolomite and/or at least one ground calcium carbonate (GCC), more preferably at least one ground calcium carbonate (GCC) and most preferably at least one ground calcium carbonate (GCC) selected from the group comprising marble, chalk, limestone and mixtures thereof.

3. The crumbles according to claim 1, wherein the crumbles comprise a) at least one further particulate filler material, preferably at least one further particulate filler material selected from the group comprising precipitated calcium carbonate (PCC), metal oxides such as titanium dioxide and/or aluminium trioxide, metal hydroxides such as aluminium tri-hydroxide, metal salts such as sulfates, silicates such as talc and/or kaolin and/or kaolin clay and/or mica, carbonates such as magnesium carbonate and/or gypsum, satin white and mixtures thereof, and/or b) on at least a part of the accessible surface area of the calcium carbonate-containing material particles a treatment layer comprising a hydrophobizing agent, preferably an aliphatic carboxylic acid having a total amount of carbon atoms from C4 to C24 and/or reaction products thereof and/or at least one mono-substituted succinic anhydride consisting of succinic anhydride mono-substituted with a group selected from a linear, branched, aliphatic and cyclic group having a total amount of carbon atoms from C2 to C30 in the substituent and/or reaction products thereof and/or a phosphoric acid ester blend of one or more phosphoric acid mono-ester and/or reaction products thereof and one or more phosphoric acid di-ester and/or reaction products thereof.

4. The crumbles according to claim 1, wherein the crumbles have a) a moisture pick up susceptibility such that its total surface moisture level is 0.6 mg/g, preferably 0.5 mg/g, more preferably 0.4 mg/g and most preferably 0.3 mg/g of the dry crumbles after exposure to an atmosphere of 50% of relative humidity for 48 hours at a temperature of 23 C., and/or b) a moisture content of from 0.2 wt.-% to 0.6 wt.-%, preferably from 0.2 wt.-% to 0.4 wt.-% and most preferably from 0.25 wt.-% to 0.35 wt.-% based on the total dry weight of the crumbles.

5. Process for the preparation of crumbles comprising at least one calcium carbonate-containing material as defined in claim 1, the process comprising the steps of: a) providing at least one calcium carbonate-containing material in the form of an aqueous slurry having solids content in the range from 5.0 to 45.0 wt.-%, based on the total weight of the slurry, b) wet grinding the at least one calcium carbonate-containing material of step a) to obtain an aqueous slurry of the at least one wet-ground calcium carbonate-containing material, wherein the particles of the at least one wet-ground calcium carbonate-containing material have a i) weight particle size d.sub.75 of 0.7 to 3.0 m, ii) weight median particle size d.sub.50 of 0.5 to 2.0 m, iii) weight particle size d.sub.25 of 0.1 to 1.0 m, as measured according to the sedimentation method, and iv) a BET specific surface area of from 4.0 to 12.0 m.sup.2/g, measured by nitrogen gas adsorption using the BET isotherm (ISO 9277:2010), c) mechanical dewatering of the aqueous slurry of step b) to obtain crumbles comprising the at least one calcium carbonate-containing material having solids content of 78.0 wt.-% to 90.0 wt.-%, based on the total weight of the crumbles.

6. The process according to claim 5, wherein the aqueous slurry of the at least one calcium carbonate-containing material of step a) is free of dispersing agents and/or wet-grinding step b) and/or mechanical dewatering step c) is/are carried out in the absence of dispersing agents.

7. The process according to claim 5, wherein the aqueous slurry of the at least one wet-ground calcium carbonate-containing material obtained in step b) has a) lower solids content than the aqueous slurry of the at least one calcium carbonate-containing material provided in step a), and/or b) solids content in the range from 10.0 to 35.0 wt.-%, based on the total weight of the slurry.

8. The process according to claim 5, wherein process step b) is carried out in the presence of at least one further particulate filler material, preferably at least one further particulate filler material selected from the group comprising precipitated calcium carbonate (PCC), metal oxides such as titanium dioxide and/or aluminium trioxide, metal hydroxides such as aluminium tri-hydroxide, metal salts such as sulfates, silicates such as talc and/or kaolin and/or kaolin clay and/or mica, carbonates such as magnesium carbonate and/or gypsum, satin white and mixtures thereof.

9. The process according to claim 5, wherein the aqueous slurry of the at least one wet-ground calcium carbonate-containing material obtained in step b) is partially dewatered to solids content in the range from 20.0 to 40.0 wt.-%, based on the total weight of the slurry, before process step c) is carried out.

10. The process according to claim 5, wherein process step c) is carried out under pressure, preferably a pressure from 20.0 bar to 140.0 bar, more preferably from 65.0 bar to 120.0 bar and most preferably from 80.0 to 110.0 bar.

11. The process according to claim 5, wherein process step c) is carried out in a vertical plate pressure filter, a tube press or a vacuum filter, preferably in a tube press.

12. The process according to claim 5, wherein the process further comprises step d) of a) treating the crumbles comprising the at least one calcium carbonate-containing material obtained in step c) with a hydrophobizing agent, preferably an aliphatic carboxylic acid having a total amount of carbon atoms from C4 to C24 and/or at least one mono-substituted succinic anhydride consisting of succinic anhydride mono-substituted with a group selected from a linear, branched, aliphatic and cyclic group having a total amount of carbon atoms from C2 to C30 in the substituent and/or a phosphoric acid ester blend of one or more phosphoric acid mono-ester and one or more phosphoric acid di-ester, to obtain surface-treated crumbles comprising on at least a part of the accessible surface area of the calcium carbonate-containing material particles a treatment layer comprising the hydrophobizing agent, and/or b) drying the crumbles comprising the at least one calcium carbonate-containing material obtained in step c) to solids content of 97.0 wt.-%, preferably from 97.0 to 99.98 wt.-% and most preferably from 97.0 to 99.98 wt.-%, based on the total weight of the crumbles, and/or c) dispersing the crumbles by using a polyacrylate-based dispersant.

13. Article comprising the crumbles comprising at least one calcium carbonate-containing material according to claim 1.

14. The article of claim 13, wherein the article is selected from the group comprising plastic, preferably films, more preferably blown films or breathable films, fibres, polyvinyl chloride, plastisols, thermosetting polymers, more preferably thermosetting unsaturated polyesters or thermosetting unsaturated polyurethanes, food, cosmetic, sealant, pharmaceutical, paper, paper coating, coating, paint, adhesive articles and mixtures thereof.

15. Use of crumbles comprising at least one calcium carbonate-containing material according to claim 1 in paper making, paper coating, food, plastic, preferably films, more preferably blown films or breathable films, fibres, polyvinyl chloride, plastisols, thermosetting polymers, more preferably thermosetting unsaturated polyesters or thermosetting unsaturated polyurethanes, agricultural, paint, coatings, adhesives, sealants, pharmaceuticals, agricultural, construction and/or cosmetic applications.

Description

EXAMPLES

1. Measurement Methods

[0251] In the following, materials and measurement methods implemented in the examples are described.

Particle Size Distribution (Mass % Particles with a Diameter<X) and Weight Median Diameter (d.sub.50) of a Particulate Material

[0252] Weight grain diameter and grain diameter mass distribution of a particulate material were determined via the sedimentation method, i.e. an analysis of sedimentation behaviour in a gravitational field. The measurement was made with a Sedigraph 5120 or a Sedigraph 5100 of Micromeritics Instrument Corporation.

[0253] 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 are dispersed using a high speed stirrer and supersonics.

BET Specific Surface Area of a Material

[0254] Throughout the present document, the specific surface area (in m.sup.2/g) of a particulate material was determined using the BET method (using nitrogen as adsorbing gas), which is well known to the skilled man (ISO 9277:1995). The total surface area (in m.sup.2) of the particulate material is then obtained by multiplication of the specific surface area and the mass (in g) of the particulate material. The method and the instrument are known to the skilled person and are commonly used to determine the specific surface of particulate materials.

Solids Content

[0255] The solids content (also known as dry weight) was determined using a Moisture Analyser HR73 from the company Mettler-Toledo, Switzerland, with the following settings: temperature of 120 C., automatic switch off 3, standard drying, 5 to 20 g of product.

Calcium Carbonate Content of a Particulate Material

[0256] For the measurement of the calcium carbonate content of a particulate material, about 10.000 grams of the dry sample (dried at 110 C. for 5 hours in an oven) were weighed in a flask/beaker and a small amount of demineralized water was added. Then, 40 mL of hydrochloric acid (25% p.a.) were added to the respective sample and after the CO.sub.2 development stopped, the mixture was boiled for about 5 min. After cooling down, the mixture was filtered through a 0.8 m cellulose-acetate filter and washed thoroughly. Then the filtrate was quantitatively rinsed to a volumetric flask with distilled water and filled up to 1000.0 ml at 20 C.

[0257] The thus obtained filtrate was then slowly titrated by pipetting 10.00 mL of the obtained filtrate (about 20 C.) into a Memotitrator-beaker and 1.0 g (0.2 g) of triethanolamine puris. and 3.0 g of MgSO.sub.47 H.sub.2O. The mixture was diluted with demineralized water up to 70 mL and then, just before the titration, 10.0 mL of 2N sodium hydroxide and 7 to 9 drops of a HHSNN-methanol solution (0.2 wt.-% of HHSNN in methanol) were added to the mixture. After the pre-dosing, the titrator stirred the mixture for 60 s and then the phototrode voltage was set to 900 to 1150 mV during titration. The calcium carbonate content was displayed in percent.

Moisture Content

[0258] The moisture content of a particulate material was determined by thermogravimetric analysis (TGA). TGA analytical methods provide information regarding losses of mass with great accuracy, and is common knowledge; it is, for example, described in Principles of Instrumental analysis, fifth edition, Skoog, Holler, Nieman, 1998 (first edition 1992) in Chapter 31 pages 798 to 800, and in many other commonly known reference works. In the present invention, thermogravimetric analysis (TGA) is performed using a Mettler Toledo TGA 851 based on a sample of 500+/50 mg and scanning temperatures from 25 C. to 350 C. at a rate of 20 C./minute under an air flow of 70 ml/min.

[0259] Alternatively, the moisture content of the particles was determined by the oven method.

Moisture Pick-Up Susceptibility

[0260] The term moisture pick up susceptibility in the meaning of the present invention refers to the amount of moisture absorbed on the surface of the calcium carbonate-containing particles and is determined in mg moisture/g of the dry crumbles after exposure to an atmosphere of 50% of relative humidity for 48 hours at a temperature of 23 C.

Pigment Whiteness, Paper Opacity, Light Scattering and CIELAB

[0261] Pigment whiteness R457 and paper opacity were measured using an ELREPHO 3000 from the company Datacolor according to ISO 2469:1994 (DIN 53145-2:2000 and DIN 53146:2000). The CIELAB L*, a*, b* coordinates were measured using an ELREPHO 3000 from the company Datacolor according to EN ISO 11664-4 and barium sulfate as standard.

Charpy Impact Strength

[0262] Charpy impact strength (23 C.2 C. and 50% relative humidity10% relative humidity) was measured according to ISO 179/1eA on extruded samples which were cut out of the extrudate in machine direction.

Breaking Force and Elongation at Break

[0263] The breaking force is the force needed to be applied on a yarn to make it break. It is expressed in Newton [N]. The elongation at break is the increase of the length produced by stretching a yarn to its breaking point. It is expressed as a percentage [%] of its initial length.

Tenacity

[0264] The tenacity is calculated from the breaking force and the linear density, and expressed in centinewton per tex [cN/tex]. The test is carried out on a dynamometer with a constant stretching speed, applicable standards for this test are EN ISO 5079 and ASTM D 3822.

Tensile Index

[0265] The tensile index is the product of tenacity [cN/tex] and the square root of the elongation at break [%].

Tensile Strength and Elongation

[0266] Tensile strength [kN/m] and the elongation at maximum load [%] are measured in machine direction (MD) and in cross machine direction (CD). The energy value according to EN ISO 10319 is calculated by the tensile strength (MD+CD)/2.

Surface Gloss

[0267] The surface gloss was measured with a Byk Spectro Guide Sphere Gloss at an angle of 60 from the plane surface according to ISO 2813:1994. The gloss value is determined by calculating the average value of n measurement. In the present set up n=10.

Filter Pressure Value

[0268] The filter pressure test provides for the Filter Pressure Value. The Filter Pressure Value FPV is defined as the increase of pressure per gram filler. This test is performed to determine the dispersion quality and/or presence of excessively coarse particles or agglomerates of mineral materials in a masterbatch. Low Filter Pressure Values refer to a good dispersion and fine material, wherein high Filter Pressure Values refer to bad dispersion and coarse or agglomerated material.

[0269] The Filter Pressure test was performed on a commercially available Collin Pressure Filter Test, Teach-Line FT-E20T-IS, according to the standard EN 13900-5. Filter type used was 14 m and 25 m, extrusion was carried out at 200 C.

K-Value of PVC:

[0270] A measure of the molecular weight of PVC based on measurements of viscosity of a PVC solution. It ranges usually between 35 and 80. Low K-values imply low molecular weight (which is easy to process but has inferior properties) and high K-values imply high molecular weight, (which is difficult to process, but has outstanding properties). In general, K-values for a particular PVC resin are provided by the resin producer either on the packaging or the accompanying technical data sheet.

2. Examples

[0271] The following crumbles were prepared:

Crumbles A:

[0272] Crumbles A of a calcium carbonate-containing material were obtained by wet grinding an aqueous slurry of calcium carbonate (marble; d.sub.50=1.6 m) having solids content of about 35.0 wt.-%, based on the total weight of the slurry. The slurry was wet ground in a vertical ball mill to a final particle size distribution as described in table 1 herein below. The slurry obtained after wet grinding had solids content of about 20.0 wt.-%, based on the total weight of the slurry.

[0273] The wet ground calcium carbonate-containing material was then dewatered by using a vertical tube press filter (Metso Corporation, Finland) operating at about 95 bars and a temperature of about 50 C. The pressure is reached by a hydraulic system. The obtained crumbles A had properties as described in table 1 below.

TABLE-US-00001 TABLE 1 Properties of the crumbles Crumbles Crumbles Crumbles Crumbles A B C D d.sub.50 [m] 1.6 0.8 1.5 1.0 <1 m (by 30 60 33.3 45 sedimentation) [wt.-%] <2 m (by 55 90 62.1 75 sedimentation) [wt.-%] sc final [wt.-%] 85-88 85 86.6 85 Brightness >94 >94 94.6 >93 Yellowness index <1.5 <1.5 1.1 <1.5 Cielab a* 0 0 0 0 Cielab b* 0.5 0.4 0.6 0.6 Cielab L* 97 97 98.2 98 BET surface area 4-5 6-7 5.7 6 [m.sup.2/g]

Crumbles B:

[0274] Crumbles B of a calcium carbonate-containing material were obtained by wet grinding an aqueous slurry of calcium carbonate (marble; d.sub.50=0.8 m) having solids content of about 35.0 wt.-%, based on the total weight of the slurry. The slurry was wet ground in a vertical ball mill to a final particle size distribution as described in table 1 herein below. The slurry obtained after wet grinding had solids content of about 20.0 wt.-%, based on the total weight of the slurry.

[0275] The wet ground calcium carbonate-containing material was then dewatered by using a vertical tube press filter (Metso Corporation, Finland) operating at about 95 bars and a temperature of about 50 C. The pressure is reached by a hydraulic system. The obtained crumbles B had properties as described in table 1 above.

[0276] The obtained crumble particles were further surface-treated by using stearic acid. 200 g of the obtained crumbles were diluted with water to solids content of 20.0 wt.-%, based on the total weight of the obtained slurry, and heated up to 80 C.

[0277] A 0.4 M solution of stearic acid was prepared by mixing 4.1 g of stearic acid with 40 ml of deionised water under stirring at a temperature of 85 C. After 30 min of stirring 2.5 g of a 30 wt.-% sodium hydroxide solution was added to the stearic acid solution (stearic acid/hydroxide mole ratio 1/1.3).

[0278] The heated sodium stearate solution was added to the crumble slurry such that a treatment level of 0.5 and 0.7 wt.-%, based on the total weight of the crumbles, respectively, was obtained and stirred for 60 min at 85 C. Subsequently, the slurry was allowed to cool down and pressure filtered afterwards to solids content of about 93.7 wt.-%, based on the total weight of the obtained product.

[0279] The obtained surface-treated crumbles B1 (treatment level: 0.5 wt.-%) and B2 (treatment level: 0.7 wt.-%) had properties as described in table 2 below.

TABLE-US-00002 TABLE 2 Properties of surface-treated crumbles B1 and B2 Crumbles Crumbles B1 B2 d.sub.50 [m] 0.89 0.9 <1 m (by 56.5 56.1 sedimentation) [wt.-%] <2 m (by 87.8 87.0 sedimentation) [wt.-%] d.sub.98 [m] 4.4 4.1 Brightness 95.4 94.8 Yellowness index 1.2 1.3 Cielab a* 0.0 0.0 Cielab b* 0.7 0.7 Cielab L* 98.5 98.3 BET surface area 6.3 6.4 [m.sup.2/g]

Crumbles C:

[0280] Crumbles C of a calcium carbonate-containing material were obtained by wet grinding an aqueous slurry of calcium carbonate (marble; d.sub.50=1.5 m) having solids content of about 35.0 wt.-%, based on the total weight of the slurry. The slurry was wet ground in a vertical ball mill to a final particle size distribution as described in table 1 herein below. The slurry obtained after wet grinding had solids content of about 20.0 wt.-%, based on the total weight of the slurry.

[0281] The wet ground calcium carbonate-containing material was then dewatered by using a vertical tube press filter (Metso Corporation, Finland) operating at about 95 bars and a temperature of about 50 C. The pressure is reached by a hydraulic system. The obtained crumbles C had properties as described in table 1 above.

[0282] The obtained crumble particles were further surface-treated by using stearic acid as described for crumbles B above. The sodium stearate solution was added to the crumble slurry such that a treatment level of 0.9 and 1.2 wt.-%, based on the total weight of the crumbles, respectively, on the crumbles was obtained.

[0283] The obtained surface-treated crumbles C1 (treatment level: 0.9 wt.-%) and C2 (treatment level: 1.2 wt.-%) had properties as described in table 3 below.

TABLE-US-00003 TABLE 3 Properties of surface-treated crumbles C1 and C2 Crumbles Crumbles C1 C2 d.sub.50 [m] 5.5 5.8 <1 m (by 33.5 37.7 sedimentation) [wt.-%] <2 m (by 63.9 67.0 sedimentation) [wt.-%] d.sub.98 [m] 5.5 5.8 Brightness 94.1 92.7 Yellowness index 1.4 1.7 Cielab a* 0.0 0.0 Cielab b* 0.8 0.9 Cielab L* 98.1 97.6 BET surface area 4.7 4.5 [m.sup.2/g]

Crumbles D:

[0284] Crumbles D of a calcium carbonate-containing material were obtained by wet grinding an aqueous slurry of calcium carbonate (marble; d.sub.50=1.0 m) having solids content of about 35.0 wt.-%, based on the total weight of the slurry. The slurry was wet ground in a vertical ball mill to a final particle size distribution as described in table 1 herein below. The slurry obtained after wet grinding had solids content of about 20.0 wt.-%, based on the total weight of the slurry.

[0285] The wet ground calcium carbonate-containing material was then dewatered by using a vertical tube press filter (Metso Corporation, Finland) operating at about 95 bars and a temperature of about 50 C. The pressure is reached by a hydraulic system. The obtained crumbles D had properties as described in table 1 above.

[0286] The obtained crumble particles were further surface-treated by using stearic acid as described for crumbles B above. The sodium stearate solution was added to the crumble slurry such that a treatment level of 0.8 wt.-%, based on the total weight of the crumbles, on the crumbles was obtained.

3. Application

[0287] The crumbles prepared above were tested in the following applications:

A) Application in PVC

[0288] The crumbles B1 and B2 were tested in the PVC profile extrusion as described in table 4 below.

TABLE-US-00004 TABLE 4 Preparation and testing of samples B1 B2 Reference Reference Reference Example (inventive) (inventive) 1 2 3 PVC K-value 66 100 (phr) 100 (phr) 100 (phr) 100 (phr) 100 (phr) (Evipol SH6630) CaZn containing 4.3 (phr) 4.3 (phr) 4.3 (phr) 4.3 (phr) 4.3 (phr) stabilizer (Stabilox CZ 2913 GN) Lubricant: 12-Hydroxy 0.2 (phr) 0.2 (phr) 0.2 (phr) 0.2 (phr) 0.2 (phr) stearic acid (Realube AIS) Lubricant: PE wax 0.15 (phr) 0.15 (phr) 0.15 (phr) 0.15 (phr) 0.15 (phr) (Realube 3010) Titanium dioxide 3.5 (phr) 3.5 (phr) 3.5 (phr) 3.5 (phr) 3.5 (phr) (Kronos 2220) Acrylic impact modifier .sup.6 (phr) .sup.6 (phr) .sup.6 (phr) .sup.6 (phr) .sup.6 (phr) (Paraloid KM 366) Crumbles 8 or 16 8 or 16 8 or 16 .sup.8 (phr) 8 or 16 (phr) (phr) (phr) (phr)

[0289] The term phr in the meaning of the present invention means parts per hundred resins. In particular, if 100 parts of polymer are used, the quantity of other ingredients is expressed in relation to this 100 parts of polymer by weight.

[0290] The reference materials are as follows: [0291] Reference 1: calcium carbonate, commercially available from Omya, Switzerland, having a d.sub.50 of 0.8 m, a d.sub.98 of 5 m and a BET specific surface area of 8 to 9 m.sup.2/g. The particles have a Cielab a* of 0.3, a Cielab b* of 1.8 and a Cielab L* of 97.5. The calcium carbonate is surface-treated by using stearic acid and has a treatment level of 0.8 to 0.9 wt.-%, based on the total weight of the calcium carbonate. [0292] Reference 2: calcium carbonate, commercially available from Omya, Switzerland, having a d.sub.50 of 0.8 m, a d.sub.98 of 4 m and a BET specific surface area of 11 m.sup.2/g. The particles have a Cielab a* of 0.2, a Cielab b* of 0.5 and a Cielab L* of 97.5. The calcium carbonate is surface-treated by using stearic acid and has a treatment level of 1.0 wt.-%, based on the total weight of the calcium carbonate. [0293] Reference 3: calcium carbonate, commercially available from Omya, Switzerland, having a d.sub.50 of 0.8 m, a d.sub.98 of 4 m and a BET specific surface area of 11 m.sup.2/g. The calcium carbonate is surface-treated by using stearic acid and has a treatment level of 2.0 wt.-%, based on the total weight of the calcium carbonate.

[0294] The components for the inventive as well as comparative examples were previously mixed using the usual hot/cold mixing process known to the skilled person, and extruded on a Gottfert extrusion line equipped with a Krauss-Maffei plastifiction unit, L/D 32, with counter rotating parallel twin screws, the screws having a diameter of 30 mm each.

[0295] The prepared extruded profiles were tested with regard to the charpy impact resistance (ISO 179/1fC) and gloss 60 []. The results can be gathered from FIGS. 1 and 2. As can be gathered from FIGS. 1 and 2, the inventive sample B1 and B2 provides for an increase in charpy impact resistance (ISO 179/1fC) with same amount (16 phr) of crumbles of the present invention in comparison to the references 1 to 3. Gloss 60 [] of the inventive samples B1 and B2 is not affected to the negative and remains within the tolerances, see FIG. 2. Further optical properties as described in Table 5 below such as brightnesssee L*-value, are also not affected to the negative and red-/yellowness-valuessee a*/b*-values, remain within the tolerances and thus the overall benefit provided by the present invention is shown.

TABLE-US-00005 TABLE 5 optical properties of extruded profiles CIELAB L* CIELAB a* CIELAB b* Samples (brightness) (green-red) (blue-yellow) Reference 1 - 8 phr 95.7 0.33 3.56 Reference 2 - 8 phr 96.2 0.47 3.57 Reference 3 - 8 phr 96.0 0.43 3.64 Reference 3 - 16 phr 95.9 0.46 3.73 B2 - 8 phr 96.0 0.48 3.55 B1 - 8 phr 96.2 0.47 3.52 B2 - 16 phr 95.9 0.46 3.73 B1 - 16 phr 95.9 0.45 3.73

B) Application in PE

[0296] The crumbles C1 and C2 were tested in PE extrusion.

[0297] The crumbles C1 and C2 of the present invention were made into a master batch of a linear low density polyethylene (LLDPE; MFI=1 g/10 min, ExxonMobil 1001) as outlined in table 6 below.

[0298] A filter pressure test was performed in order to determine the filter pressure value FPV of such LLDPE master batch and compared to the FPV a master batch comprising a calcium carbonate of the prior art. The results are given in Table 6 below.

TABLE-US-00006 TABLE 6 composition of the master batch and FPV Crumbles C1 Crumbles C2 Reference 4 Amount of 65 65 65 crumbles [wt.-%] Amount of LLDPE 35 35 35 Exxon Mobil 1001 [wt.-%] Filter pressure at 1.3 1.7 1.6 14 m pore size [bar/g]

[0299] The reference material is as follows: [0300] Reference 4: calcium carbonate, commercially available from Omya, Switzerland, having a d.sub.50 of 1.7 m, a d.sub.98 of 8 m and a BET specific surface area of 4 to 5 m.sup.2/g. The particles have a Cielab a* of 0.1, a Cielab b* of 1.1 and a Cielab L* of 98.5. The calcium carbonate is surface-treated by using stearic acid and has a treatment level of 0.7 to 0.8 wt.-%, based on the total weight of the calcium carbonate.

[0301] The crumbles of the present invention clearly show their beneficial properties over reference 4 when made into a master batch. The pressure on the pore filter at 14 m shows that the crumbles C1 of to the present invention, shows reduced pressure build up at the pore size filter, thus demonstrating the advantageous properties, the improved dispersion of the crumble particles in the polymer matrix.

[0302] Further to this, said filled LLDPE master batches were made into blown film by means known to the skilled person. Samples of the said blown films comprising the crumbles C1 and C2 of the present invention and samples of blown films comprising the reference 4 are compared hereafter in table 7. Different amounts of filled master batch were mixed with a further LLDPE (Dowlex 5056G; C8-LLDPE, MFI=1 g/10 min,) and blown films were made from these mixtures on a Dr. Collin film line. The content of the crumbles C1 and C2 and of the reference 4 in the final films were 20 wt.-%, based on the total weight of the respective final film. Films having a width of 22 cm, a film grammage of 35 g/m.sup.2 and a frost line position at 15 cm were prepared.

[0303] The mechanical properties of the prepared films are outlined in table 7 below.

TABLE-US-00007 TABLE 7 mechanical properties of prepared films Formulation 1 2 3 CaCO.sub.3 C1 C2 Reference 4 Universal tests Yield, MD.sup.1 [N/mm.sup.2] 9.6 9.8 9.8 Yield, CD.sup.2 [N/mm.sup.2] 9.8 10.0 9.9 Elongation at break, 536 541 505 MD.sup.1 [%] Elongation at break, CD.sup.2 572 574 540 [%] Force at break, MD.sup.1 36.7 38.5 31.2 [N/mm.sup.2] Force at break, CD.sup.2 33.1 33.3 28.5 [N/mm.sup.2] E-modulus, MD.sup.1 [N/mm.sup.2] 283 291 301 E-modulus, CD.sup.2 [N/mm.sup.2] 312 318 321 .sup.1MD refers to machine direction, .sup.2CD refers to cross direction.

[0304] As can be seen from table 7, the inventive crumbles C1 and C2 gave better force at break as well as dart drop resistance compared to the reference 4.