Pelletization Of A Phosphite Polymer Stabilizer

Abstract

The invention relates to a method for manufacturing a pellet in a pellet mill, which method comprises the steps of (A) pressing a mixture for compaction by a roller through a nozzle to obtain a strand, and (B) comminuting the strand to obtain the pellet, wherein the mixture for compaction comprises (i) 87 to 97 wt. % of a polymer stabilizer, which is tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 100 J/g at 101.32 kPa.

The pellet is useful for a dust-free handling of its polymer stabilizer at a manufacturing of the stabilized polymer. Furthermore, a method for stabilizing a polymer, which is a polyolefin, a polystyrene or a mixture thereof, is disclosed, which comprises the dosing of the pellet to the polymer.

Claims

1. A method for manufacturing a pellet in a pellet mill, the pellet mill comprising a roller and a die with a nozzle, the method comprising: (A) pressing a mixture for compaction by the roller through the nozzle to obtain a strand, and (B) comminuting the strand to obtain the pellet, wherein the mixture for compaction comprises (i) 87 to 97 wt. % of a polymer stabilizer, which is tris(2,4-ditertbutylphenyl) phosphite, and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 100 J/g at 101.32 kPa, and wherein the wt. % is based on the weight of the mixture for compaction.

2. The method according to claim 1, wherein the melting enthalpy is determined by a differential scanning calorimetry according to EN ISO 11357-3.

3. The method according to claim 1, wherein the processing aid possesses a weight average molecular weight above 10000 Da and below 40000 Da.

4. The method according to claim 1, wherein the processing aid possesses a melting peak temperature above 50° C. and below 85° C.

5. The method according to claim 4, wherein the melting peak temperature is determined by a differential scanning calorimetry according to EN ISO 11357-3.

6. The method according to claim 1, wherein the processing aid is a propylene-ethylene copolymer, which is a wax.

7. The method according to claim 1, wherein the mixture for compaction comprises (i) 89 to 96 wt. % of the polymer stabilizer, (ii) 4 to 11 wt. % of the processing aid.

8. The method according to claim 1, wherein the strand has a surface temperature above 50° C. and below 110° C.

9. The method according to claim 1, wherein the method comprises a step (pre-A) feeding the mixture for compaction into the pellet mill, wherein the mixture for compaction is in the form of a powder, and the step (pre-A) occurs before the step (A).

10. The method according to claim 1, wherein the pellet mill is a ring die pellet mill, wherein the die has a geometric form of a ring with an inner side and an outer side and the nozzle represent a pass from the inner side to the outer side, or the pellet mill is a flat die pellet mill, wherein the die has a geometric form of a planar plate with an upper side and a lower side and the nozzle represents a pass from the upper side to the lower side.

11. The method according to claim 10, wherein at the ring die pellet mill, the ring is rotating and the roller possesses a rotation axis, which is stationary, and at the flat die pellet mill, the die is stationary and the roller possesses a rotation axis, which is rotating.

12. The method according to claim 1, wherein the nozzle has a nozzle diameter and a press length, and a ratio of the press length to the nozzle diameter is from 2 to 8.

13. The method according to claim 1, wherein the roller surface is corrugated.

14. The method according to claim 1, wherein the pellet mill is a ring die pellet mill.

15. The method according to claim 1, wherein the pellet mill comprises two or more rollers and the die comprises two or more nozzles.

16. A pellet, comprising: (i) 87 to 97 wt. % of a polymer stabilizer, which is tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer possessing a melting enthalpy below 100 J/g at 101.32 kPa, and wherein the wt. % is based on the weight of the pellet.

17. The pellet according to claim 16, which has a shape of a round rod and the round rod has a diameter of a circle, which is between 2 mm and 4 mm.

18. The pellet according to claim 17, which has a length of 1 to 3 times of the diameter of a circle.

19. A method of using a pellet according to claims 16 for a dust-free handling of its components at manufacturing of a stabilized polymer, wherein the polymer is a polyolefin, a polystyrene or a mixture thereof

20. A method for manufacturing of a stabilized polymer, which comprises the steps of (AP) dosing a pellet according to claims 16 into a polymer to obtain a pellet-polymer mixture, (BP) exposing the pellet-polymer mixture to a temperature in the range of 120 to 340° C. under mechanical stirring to obtain a stabilized polymer, wherein the polymer is a polyolefin, a polystyrene or a mixture thereof

21. A mixture for compaction, comprising: (i) 87 to 97 wt. % of a polymer stabilizer in the physical form of a powder, which is tris(2,4-ditert-butylphenyl) phosphite, and (ii) 3 to 13 wt. % of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer possessing a melting enthalpy below 100 J/g at 101.32 kPa, compaction. and wherein the wt. % is based on the weight of the mixture for

Description

[0271] FIG. 1 shows pellets obtained from example E-1-1, which are placed on a millimeter paper.

[0272] FIG. 2 shows pellets obtained from example E-1-2, which are placed on a millimeter paper.

[0273] FIG. 3 shows pellets obtained from example E-1-3, which are placed on a millimeter paper.

[0274] FIG. 4 shows pellets obtained from example E-1-4, which are placed on a millimeter paper.

[0275] FIG. 5 shows pellets obtained from example E-1-5, which are placed on a millimeter paper.

[0276] FIG. 6 shows pellets obtained from example E-1-6, which are placed on a millimeter paper.

[0277] FIG. 7 shows pellets obtained from example E-1-7, which are placed on a millimeter paper.

[0278] FIG. 8 shows pellets obtained from example E-1-8, which are placed on a millimeter paper.

[0279] The following examples illustrate further the invention without limiting it. Percentage values are percentage by weight if not stated differently.

A) Methods for Characterization

[0280] Mean particle size is determined, if not otherwise stated, by a Camsizer P4 from the Company Retsch Technology GmbH via digital image analysis. The measuring principle is dynamic image analysis according to ISO 13322-2.

[0281] Bulk density is measured complying to DIN EN ISO 17892-3.

[0282] Melt flow index of a polymer is measured according to ISO 1133 on a Goettfert MI-Robo with the specifically stated parameters.

[0283] Differential scanning calorimetry (DSC) is measured according to EN ISO 11357-3 at atmospheric pressure. Heating cycles are (a) 0° C. to 200° C. at 10° C./min and 30 mL/min N.sub.2, (b) 200° C. to 0° C. at 10° C./min and 30 mL/min N.sub.2, (C) 0° C. to 200° C. at 10° C./min and 30 mL/min N.sub.2. Melting range, melting peak temperature and melting enthalpy are determined at heating cycle (c).

[0284] High temperature gel permeation chromatography (HT-GPC) is measured according to ISO 16014-4. As an apparatus, an Agilent PL-GPC 220 with RI detector is used. As a precolumn, one Agilent PFgel Olexis Guard 50×7.5 mm column (part No. PL1110-1400) is used. As columns, three Agilent PLgel Olexis 13 μm 300×7.5 mm columns (part No. PL1110-6400) are used. The column temperature is 150° C. The calibration standards are polystyrene and High EasiVial GPC/SEC calibration standards from Agilent (part No. PL2010-0201 and part No. PL2010-0202). Trichlorobenzene is used as the eluent with a flow rate of 1 mL/min, a sample concentration of 3 mg/mL and an injection volume of 200 μL. A determined number average molecular weight Mn and a determined weight average molecular weight Mw are used to calculate a polydispersity index (PD) as the ratio between Mw and Mn.

[0285] Sieve analysis is conducted by a Camsizer P4 from the company Retsch Technology GmbH via digital image analysis. The measuring principle is dynamic image analysis according to ISO 13322-2) with D10, D50 and D90 values.

[0286] The Norner attrition test is a test using a vibrating sieve shaker and glass beads to mechanically treat the tested form. An initial sieve analysis is conducted for 1 minute followed by further sieving using glass balls on the sieve decks to mechanically impact the material and measure the change of the sieve fractions after 5, 10 and 20 minutes. Sieves selected are bottom up: 200 μm, 500 μm, 1 mm, 1.6 mm, 2.5 mm and 4 mm. The used glass balls (company Sigmund Lindner GmbH, type P) are of 16 mm ±0.02 mm, weight 5.36 g/glass ball and made of soda lime glass with fine matt surface. The test procedure is as follow: [0287] 1. The sieve shaker without glass beads is charged with 50 g of a sample and the sieving with amplitude 1 mm is conducted for 1 minute. Measuring of mass on each sieve tray and sieve pan. [0288] 2. Add 8 glass balls on sieve 500 μm; 9 glass balls on sieve 1.0 mm, 10 on sieve 1.6 mm and 11 on sieve 2.5 mm. Proceed sieving for 5 minutes then measure mass on each sieve tray and sieve pan. [0289] 3. Proceed sieving for another 5 minutes, repeat weighing procedure. [0290] 4. Proceed sieving for another 10 minutes, repeat weighing procedure.

[0291] A Retsch Sieve Shaker AS 200 control from the company Retsch GmbH is used as sieve shaker.

[0292] Total fines are the sum of all material, which is collected from bottom plate and 200 μm mesh sieve. Accordingly, the fragments of a sample, which are generated under attrition stress and fall through a 500 μm mesh sieve (<500 μm), are considered fines. The particle size fraction in wt. % <500 μm after 20 minutes is the key result (Norner value) to determine abrasion and impact resistance of the tested form. The range of results can vary from 0% for extremely stable to 100% for extremely unstable.

[0293] An average weight of pellets is measured by taking a certain number of pellets (around 45 pellets), weighing the certain number of pellets to obtain an overall weight and dividing the overall weight by the certain number of the pellets.

[0294] An average length of the pellets is calculated by multiplying the average weight of pellets with an assumed density of 0.95 g/cm.sup.3 and dividing by the circular area of a circle with a pellet diameter of 3 mm.

B) Starting Material

SM-PS-1: Irgafos 168

[0295] Irgafos 168 (TM, commercially available from BASF SE, melting point between 180-183° C.), which contains tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4) as depicted below

##STR00002##

in the form of a powder, i.e. a loose bulk material with a bulk density of 467 g/L and a mean particle size of 400 μm.

SM-PA-1: Licocene PP 1302

[0296] Licocene PP 1302 (TM, commercially available from Clariant, employed commercial technical form: fine grain) is a propylene-ethylene copolymer wax (CAS-No. 9010-79-1), which is synthesized with a metallocene catalyst from propylene and ethylene. Branching of the long polymeric chains occurs by short chains (—CH.sub.3). Some physical-chemical properties are measured and depicted in table B-1.

[0297] Technical data sheet states a density at 23° C. according to ISO 1183 of 0.87 g/cm.sub.3.

[0298] Technical data sheet states a drop point according to ASTM D 3954 of 87-93° C.

[0299] Technical data sheet states a viscosity at 170° C. according to DIN 53019 of 150-250 mPas.

[0300] Sieve analysis of the material in the technical form fine grain is measured and depicted in table B-2. A bulk density of 338 g/L is measured. The material in its technical form fine grain is employed for compaction.

SM-PA-2: Petrolite EP-700

[0301] Petrolite EP-700 (TM, commercially available from Baker Hughes) is a propylene-ethylene copolymer wax (CAS-No. 9010-79-1). Controlled branching of the long polymeric chains occurs by short chains from propylene (—CH.sub.3). Some physical-chemical properties are measured and depicted in table B-1.

[0302] Technical data sheet states a drop melting point according to ASTM D-127 of 96° C.

[0303] Technical data sheet states a viscosity at 99° C. of 12 pcs (120 mPas).

[0304] Petrolite EP-700 is milled in a disc mill PF 300 from Pallmann. Sieve analysis of the obtained ground material is measured and depicted in table B-2. A bulk density of the ground material of 473 g/L is measured. The ground material is employed for compaction.

SM-PA-3: Luwax AL-3

[0305] Luwax AL-3 (TM, commercially available from BASF as a powder) is a polyethylene wax (CAS-No. 9002-88-4), which is synthesized by a high-pressure polymerization. Branching of the long polymeric chains occurs by long chains (—[CH.sub.2—CH.sub.2—].sub.n—H). Some physical-chemical properties are measured and depicted in table B-1.

[0306] Technical data sheet states a density at 23° C. according to DIN 53479 and ASTM D-792 of 0.91-0.925 g/cm.sub.3.

[0307] Technical data sheet states a drop point (Ubbelohde) according to DIN 51801 and ASTM D-3954 of 101-112° C.

[0308] Technical data sheet states a melting point (DSC) according to DIN 51007 and ASTM D-3418 of 102-108° C.

[0309] Technical data sheet states a melt viscosity at 120° C. according to DIN 51562 and ASTM D2162 of 135-240 mm.sup.2/s.

[0310] Sieve analysis of the material in the technical form powder is measured and depicted in table B-2. A bulk density of 495 g/L is measured. The material in its technical form is employed for compaction.

SM-PA-4: Dow PG 7008

[0311] Dow PG 7008 (TM, commercially available from Dow Chemicals) is a low density polyethylene (CAS-No. 9002-88-4). Some physical-chemical properties are measured and depicted in table B-1

[0312] Technical data sheet states a density at 23° C. according to ASTM D-792 of 0.918 g/cm.sub.3.

[0313] Technical data sheet states a melting temperature (DSC) of 106° C.

[0314] Technical data sheet states a vicat softening temperature according to ISO 306/A of 89.0° C.

[0315] Technical data sheet states a melt index (190° C./2.16 kg) according to ISO 1133 of 7.7 g/10 min.

[0316] Dow PG 7008 is milled in a disc mill PF 300 from Pallmann. Sieve analysis of the obtained ground material is measured and depicted in table B-2. A bulk density of the ground material of 285 g/L is measured. The ground material is employed for compaction.

SM-PA-5: Borflow HL 708 FB

[0317] Borflow HL 708 FB (TM, commercially available from Borealis) is a polypropylene (CAS-No. 9003-07-0). Some physical-chemical properties are measured and depicted in table B-1.

[0318] Technical data sheet states a melting temperature (DSC) of 158° C. Technical data sheet states a melt index (130° C./2.16 kg) according to ISO 1133 of 800 g/10 min.

[0319] Borflow HL 708 FB is milled in a disc mill PF 300 from Pallmann. Sieve analysis of the obtained ground material is measured and depicted in table B-2. A bulk density of the ground material of 365 g/L is measured. The ground material is employed for compaction.

TABLE-US-00001 TABLE B-1 measured physical-chemical properties of starting materials processing aids DSC measurement melting melting peak melting HT-GPC measurement starting commercial range temperature enthalpy Mn Mw material name [° C.] [° C.] [J/g] [Da] [Da] PD SM-PA-1 Licocene 24-95 76 23 6833 17285 2.53 PP 1302 SM-PA-2 Petrolite  27-104 88 218 1335 1532 1.15 EP-700 SM-PA-3 Luwax AL-  24-112 105 127 3128 7613 2.43 3 SM-PA-4 Dow PG  25-116 106 117 30176 367733 12.2 7008 SM-PA-5 Borflow HL 120-173 157 109 25132 189565 7.54 708 FB

TABLE-US-00002 TABLE B-2 sieve analysis starting material Q3 10% [mm] Q3 50% [mm] Q3 90% [mm] SM-PA-1 0.414 0.836 1.583 SM-PA-2 (ground) 0.324 0.710 1.538 SM-PA-3 0.302 0.740 1.521 SM-PA-4 (ground) 0.225 0.484 1.091 SM-PA-5 (ground) 0.359 0.716 1.145

C) Preparation of Mixtures for Compaction

[0320] Mixtures for compaction consisting of a polymer stabilizer and a processing aid are prepared by blending the starting materials as depicted in table C-1 in a 100-L MTI blender for 5 minutes at room temperature.

TABLE-US-00003 TABLE C-1 mixtures for compaction polymer amount processing amount physical mixture-No. stabilizer [%] aid [%] form .sup.c) C-M-1 .sup.a) SM-PS-1 92 SM-PA-1 8 powder C-M-2 .sup.a) SM-PS-1 95 SM-PA-1 5 powder C-M-3 .sup.b) SM-PS-1 92 SM-PA-2 8 powder C-M-4 .sup.b) SM-PS-1 92 SM-PA-3 8 powder C-M-5 .sup.b) SM-PS-1 92 SM-PA-4 8 powder C-M-6 .sup.b) SM-PS-1 92 SM-PA-5 8 powder Food notes: .sup.a) inventive .sup.b) comparative .sup.c) at room temperature and atmospheric pressure

D) Flakes by Roll Compaction

[0321] For example D-1-1, starting material SM-PS-1 (100%) is press-agglomerated via a roll compaction process to obtain flakes for comparison. SM-PS-1 in powder form in a hopper is force-fed via a feeding screw into a compaction zone. The compaction zone is formed by a remaining gap between two rolls with slightly scratched surfaces, which are rotating towards each other. The rolls are cooled with cold water to keep the temperature close to room temperature. A suitable laboratory roll compactor is for example model WP 50N/75 (roll diameter: 150 mm, roll length: 75 mm, maximum press capacity: 12.8 t, maximum linear load: 1.71 t/cm) from the company Alexanderwerk GmbH in Germany. The compacted starting material, which leaves the compaction zone as plates, is granulated via a sieve granulator with a 1.6 mm sieve, for example model GLA-ORV-0215 from company Frewitt Ltd from Switzerland is suitable, to create free flowing flakes (=flakes of D-1-1). A Norner attrition test is conducted for the flakes of D-1-1 and the result is depicted in table E-1.

E) Pellets by a Compaction with a Ring-Die Pellet Mill

[0322] A ring-die pellet mill, i.e. a Muench Pelletizer RMP 250, is used for compaction trials of materials as stated in table E-1. A Muench ring-die pellet mill is depicted for example in the article “Produktgestaltung über mechanisches Agglomerieren von Pulvern”, W. Raehse, Chemie Ingeneur Technik, 2015, 87, No.7, 881-902 at picture 18 on p. 898. The Muench Pelletizer RMP 250 possesses a rotatable ring die, which is equipped with nozzles, e.g. nozzles with a nozzle diameter of 3 mm and a press length of 15 mm or 18 mm. The inner diameter of the ring die is 250 mm and its width is around 4 cm. A row with two or three nozzles fits to this width. The nozzles expand with an angle of 60° to the inner side of the ring die. The nozzle diameter is defined herein as the smallest diameter of the cylindric channel of the nozzle and press length is a distance, where the smallest diameter applies. The cylindric channel of the nozzle might expand after the press length, but the expanded part of the cylindric channel does not contribute for building up friction by the material to be compacted. Here, the channels of the nozzles are not expanded. The specifically applied nozzle diameter and press lengths are stated in table E-1. The material for compaction is dosed at room temperature by a volumetric single screw feeder, which is placed above the pellet press section of the ring-die pellet mill, by gravimetry into the pellet press section, which comprises the die with its nozzles and two rollers. The rollers, each with a diameter of 96 mm and a width of 30 mm, have a corrugated surface. In the pellet press section, the two rollers push the material into the nozzles of the rotating ring-die, where the material is compacted and heated up by shear forces to a temperature, at which the processing aid starts to soften and in a sintering process the compacted material is granulated to cylindrical pellets. For beginning the process, the rotation of the ring die is set to a circumferential velocity of around 4 m/s at the inner surface of the ring die, i.e. at a distance of 12.5 cm from an axis of rotation of the ring die. The material for compaction is fed as a powder into the press section. An initial starting phase of around 15 minutes is necessary until a stable running of the process is achieved. While initially a powder of the material for compaction is flowing through the nozzles, this changes towards formation of a strand at some materials for compaction and the ring die, the rollers and the nozzles are reaching a stable temperature. A temperature, which would be too high for a material for compaction, can result in a generation of a pasty mass, which blocks a further feeding of the material for compaction. At the outlet of the nozzle, the strand is cut/broken by two knifes with an adjustable distance to the ring die to pellets with a length of around 1 to 3 times of the diameters of the pellets, i.e. around 3 mm to 9 mm. Ideally, the variation in length is minimal but a certain variation cannot be avoided due to the cutting/breaking. Table E-1 states whether pellets are obtained and thus also whether a strand forms. Once the process is running stable, the temperature of the material exiting the nozzles in the die is measured by an IR-temperature sensor through measuring contactlessly the emitted IR irradiation and stated in table E-1 as surface temperature of the strand. Statistically, the emitted IR irradiation of the outer surface of the ring is also included. However at a process running stable, the ring die has warmed up close to the surface temperature of the strand. The ring die itself is not heated (with the exception of example E-1-4) or cooled but experiences a warming due to the occurring friction of the material for compaction. The obtained pellets are sieved with a 1.6 mm sieve (200 mm diameter vibrating lab sieve) to separate fines from the obtained pellets. The amount of fines removed by sieving based on the overall amount of material for compaction is stated in table E-1. The removed fines can be directly reused as material to be compacted. The pellets have cooled down to room temperature. If pellets are obtained, a Norner attrition test of the pellets after sieving is conducted and results are depicted in table E-1. Further characterizations of the obtained pellets are depicted in table E-2. Pictures of the pellets obtained at examples E-1-1 to E-1-8 are depicted at FIG. 1 to FIG. 8.

TABLE-US-00004 TABLE E-1 ring-die pellet mill compactions and attrition test results surface temper- material ature of for nozzle the removed Norner example com- composition size .sup.d) strand fines test No. paction [%] [mm] [° C.] pellets [%] [%] E-1-1 .sup.a) C-M-2 SM-PS-1 (95) 3 × 18 96 yes 12.0 46 SM-PA-1 (5) E-1-2 .sup.a) C-M-1 SM-PS-1 (92) 3 × 18 99 yes 11.5 21 SM-PA-1 (8) E-1-3 .sup.a) C-M-1 SM-PS-1 (92) 3 × 15 63 yes 6.6 9 SM-PA-1 (8) E-1-4 .sup.b) SM-PS-1 SM-PS-1 (100) 3 × 15 74 yes .sup.e) 20 96 E-1-5 .sup.b) C-M-3 SM-PS-1 (92) 3 × 15 77 yes 8.8 97 SM-PA-2 (8) E-1-6 .sup.b) C-M-4 SM-PS-1 (92) 3 × 15 82 yes 18.0 68 SM-PA-3 (8) E-1-7 .sup.b) C-M-5 SM-PS-1 (92) 3 × 15 83 yes 45.0 80 SM-PA-4 (8) E-1-8 .sup.b) C-M-6 SM-PS-1 (92) 3 × 15 95 yes 12.0 89 SM-PA-5 (8) D-1-1 .sup.b),c) SM-PS-1 SM-PS-1 (100) roll com- close to flakes — 98 paction room temper- ature Food notes: .sup.a) inventive .sup.b) comparative .sup.c) example of a roll compaction as described at D) .sup.d) nozzle diameter × press length .sup.e) in deviation from the general procedure, the nozzles and the ring are initially pre-heated to 120° C. before the initial starting phase to reduce the starting phase time - however, the process runs unstable with a lower throughput than at the other examples E-1-1 to E-1-8

[0323] From the results of the table E-1: [0324] example D-1-1 shows that SM-PS-1 (Irgafos 168) can be cold-compacted to flakes, but the Norner attrition test results of the flakes are poor; [0325] example E-1-4 shows that SM-PS-1 (Irgafos 168) without a processing aid requires for pelletization in a ring-die pellet mill a special pre-heating/it is concluded that SM-PS-1 itself has a too high melting point and requires a processing aid as a binder to allow a formation of stable pellets; [0326] example E-1-2 versus example E-1-3 shows that a higher die length leads by more friction to a higher process temperatue, which however does not lead to a better Norner attrition test result; [0327] example E-1-3 versus example E-1-4 shows that SM-PA-1 (Licocene 1302) leads to pellets with a significantly better Norner attrition test result than without a processing aid; [0328] example E-1-2 versus example E-1-5 shows than SM-PA-1 (Licocene 1302) leads to pellets with a significantly better Norner attrition test result than SM-PA-2 (Petrolite EP-700) despite of both processing aids being a propylene-ethylene copolymer wax; [0329] example E-1-5 and E-1-8 show that the amount of fines, which are generated at the process itself and removed by the 1.6 mm sieve, is not a reliable indicator for a beneficial Norner attrition test result.

TABLE-US-00005 TABLE E-2 pellet characterization material average average for pellet pellet pellet Norner example com- composition diameter .sup.c) length .sup.d) weight picture test .sup.e) No paction [%] [mm] [mm] [mg] at FIG. [%] E-1-1 .sup.a) C-M-2 SM-PS-1 (95) 3 3.7 25.1 1 46 SM-PA-1 (5) E-1-2 .sup.a) C-M-1 SM-PS-1 (92) 3 4.0 26.8 2 21 SM-PA-1 (8) E-1-3 .sup.a) C-M-1 SM-PS-1 (92) 3 5.1 33.9 3 9 SM-PA-1 (8) E-1-4 .sup.b) SM-PS-1 SM-PS-1 (100) 3 1.3 8.6 4 96 E-1-5 .sup.b) C-M-3 SM-PS-1 (92) 3 3.7 25.1 5 97 SM-PA-2 (8) E-1-6 .sup.b) C-M-4 SM-PS-1 (92) 3 3.9 26.0 6 68 SM-PA-3 (8) E-1-7 .sup.b) C-M-5 SM-PS-1 (92) 3 4.9 33.0 7 80 SM-PA-4 (8) E-1-8 .sup.b) C-M-6 SM-PS-1 (92) 3 3.1 20.5 8 89 SM-PA-5 (8) Food notes: .sup.a) inventive .sup.b) comparative .sup.c) caused by the diameter of the nozzles .sup.d) calculated from average pellet weight .sup.e) results from table E-1 depicted again

[0330] From the results of the table E-2: [0331] example E-1-4 shows that SM-PS-1 without a processing aid leads only to pellets with a low average weight; [0332] example E-1-7 shows that a high average weight is not a reliable indicator for a beneficial Norner attrition test result; [0333] the obtained pellets look at the pictures rather similar with the exception of the pellets obtained at example E-1-4 and are not a reliable indicator for a beneficial Norner attrition test result.