PELLETIZATION OF A POLYMER STABILIZER MIXTURE

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 mixture polymer stabilizer mixture, which comprises the polymer stabilizers (i-1) 45 to 55 wt. % of tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), (i-2) 45 to 55 wt. % of tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)-propionyloxymethyl]methane (CAS-No. 6683-19-8), and wt. % of the polymer stabilizers (i-1) and (i-2) are based on the weight of the polymer stabilizer mixture, and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 20 J/g at 101.32 kPa. The pellet is useful for a dust-free handling of its polymer stabilizer mixture at a manufacturing of a 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.-25. (canceled)

26. A method for manufacturing a pellet in a pellet mill, which comprises a roller and a die with a nozzle, which method comprises the steps of (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 the components (i) 87 to 97 wt. % of a polymer stabilizer mixture, which comprises the polymer stabilizers (i-1) 45 to 55 wt. % of tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), (i-2) 45 to 55 wt. % of tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)propionyloxymethyl]methane (CAS-No. 6683-19-8), and wt. % of the polymer stabilizers (i-1) and (i-2) are based on the weight of the polymer stabilizer mixture, and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 20 J/g at 101.32 kPa, wherein the melting enthalpy is determined by a differential scanning calorimetry according to EN ISO 11357-3; and wt. % of the components (i) and (ii) are based on the weight of the mixture for compaction.

27. The method according to claim 26, wherein the processing aid possesses a weight average molecular weight above 30000 Da and below 60000 Da and wherein the weight average molecular weight is determined by gel permeation chromatography (GPC).

28. The method according to claim 26, wherein the processing aid possesses a melting peak temperature above 50? C. and below 85? C. and the melting peak temperature is determined by a differential scanning calorimetry according to EN ISO 11357-3.

29. The method according to claim 26, wherein the processing aid possesses a viscosity at 170? C. according to DIN 53019 above 1000 mPas and below 2500 mPas.

30. The method according to claim 26, wherein the processing aid is a propylene-ethylene copolymer, which is a wax.

31. The method according to claim 26, wherein melting enthalpy of the processing aid is above 8 J/g and below 19 J/g.

32. The method according to claim 26, wherein the mixture for compaction comprises (i) 89 to 96 wt. % of the polymer stabilizer mixture, and (ii) 4 to 11 wt. % of the processing aid.

33. The method according to claim 26, wherein the strand has a surface temperature above 45? C. and below 110? C. determined by measurement of its infrared irradiation.

34. The method according to claim 26, 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).

35. The method according to claim 26, 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.

36. A pellet, which comprises the components (i) 87 to 97 wt. % of a polymer stabilizer mixture, which comprises the polymer stabilizers (i-1) 45 to 55 wt. % of tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), (i-2) 45 to 55 wt. % of tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)-propionyloxymethyl]methane (CAS-No. 6683-19-8), and wt. % of the stabilizers (i-1) and (i-2) are based on the weight of the polymer stabilizer mixture, and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 20 J/g at 101.32 kPa, wherein the melting enthalpy is determined by a differential scanning calorimetry according to EN ISO 11357-3; and wt. % of the components (i) and (ii) are based on the weight of the pellet.

37. The pellet according to claim 36, 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 and has a length of 1 to 3 times of the diameter of a circle.

38. A use of a pellet as defined in claim 36 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.

39. A method for manufacturing of a stabilized polymer, which comprises the steps of (AP) dosing a pellet as defined in claim 36 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.

40. A mixture for compaction, which comprises the components (i) 87 to 97 wt. % of a polymer stabilizer mixture in the physical form of a powder, which comprises the polymer stabilizers (i-1) 45 to 55 wt. % of tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), (i-2) 45 to 55 wt. % of tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)-propionyloxymethyl]methane (CAS-No. 6683-19-8), and wt. % of the polymer stabilizers (i-1) and (i-2) are based on the weight of the polymer stabilizer mixture, and (ii) 3 to 13 wt. % of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 20 J/g at 101.32 kPa, wherein the melting enthalpy is determined by a differential scanning calorimetry according to EN ISO 11357-3; and wt. % of the components (i) and (ii) are based on the weight of the mixture for compaction.

Description

[0203] The weight percentages of the components (i) and (ii) of the pellet are based on the weight of the pellet. Accordingly, the weight percentages of all components contained in the pellet, which includes the components (i) and (ii), summarizes to overall 100 wt. %. In other words, the sum of all components is 100 wt. %. The sum of all components comprises beneath the components (i) and (ii) also a potential further ingredient. The sum of components (i) and (ii) is below or equal to 100 wt. %.

[0204] FIG. 11 shows flakes obtained from example D-11-1, which are placed on a millimeter paper.

[0205] FIG. 12 shows pellets obtained from example E-11-2, which are placed on a millimeter paper.

[0206] FIG. 13 shows pellets obtained from example E-11-3, which are placed on a millimeter paper.

[0207] FIG. 14 shows pellets obtained from example E-11-4, which are placed on a millimeter paper.

[0208] FIG. 15 shows pellets obtained from example E-11-5, which are placed on a millimeter paper.

[0209] FIG. 16 shows pellets obtained from example E-11-6, which are placed on a millimeter paper.

[0210] FIG. 17 shows pellets obtained from example E-11-7, which are placed on a millimeter paper.

[0211] FIG. 18 shows pellets obtained from example E-11-8, which are placed on a millimeter paper.

[0212] FIG. 19 shows pellets obtained from example E-11-9, which are placed on a millimeter paper.

[0213] The following examples illustrate further the invention without limiting it. Percentage values are percentage by weight if not stated differently.

A) Methods for Characterization

[0214] 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 a dynamic image analysis according to ISO 13322-2.

[0215] Bulk density is measured complying to DIN EN ISO 17892-3.

[0216] Melt flow index of a polymer is measured according to ISO 1133 on a Goettfert MI-Robo with the specifically stated parameters.

[0217] 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).

[0218] 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 ?m 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 ?L. 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.

[0219] Sieve analysis is conducted by a Camsizer P4 from the company Retsch Technology GmbH via digital image analysis. The measuring principle is a dynamic image analysis according to ISO 13322-2) with D10, D50 and D90 values.

[0220] 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 ?m, 500 ?m, 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.

[0221] The test procedure is as follow: [0222] 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. [0223] 2. Add 8 glass balls on sieve 500 ?m; 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. [0224] 3. Proceed sieving for another 5 minutes, repeat weighing procedure. [0225] 4. Proceed sieving for another 10 minutes, repeat weighing procedure.

[0226] A Retsch Sieve Shaker AS 200 control from the company Retsch GmbH is used as sieve shaker.

[0227] Total fines are the sum of all material, which is collected from bottom plate and 200 ?m mesh sieve. Accordingly, the fragments of a sample, which are generated under attrition stress and fall through a 500 ?m mesh sieve (<500 ?m), are considered fines. The particle size fraction in wt. %<500 ?m 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.

[0228] An average weight of pellets is measured by taking a certain number of pellets (around 60 pellets), weighing the certain number of pellets to obtain an overall weight and dividing the overall weight by the certain number of the pellets.

[0229] 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

[0230] 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

##STR00003##

[0231] 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 ?m.

SM-PS-2: Irganox 1010

[0232] Irganox 1010 (TM, commercially available from BASF SE, melting point between 113-126? C.), which contains tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)-propionyloxymethyl]methane (CAS-No. 6683-19-8) as depicted below

##STR00004##

[0233] in the form of a powder, i.e. a loose bulk material with a bulk density of 530-630 g/L and a mean particle size of 141 ?m.

SM-PA-1: Licocene PP 1302

[0234] 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.

[0235] Technical data sheet states a density at 23? C. according to ISO 1183 of 0.87 g/cm.sup.3.

[0236] Technical data sheet states a drop point according to ASTM D 3954 of 87-93? C.

[0237] Technical data sheet states a viscosity at 170? C. according to DIN 53019 of 150-250 mPas. 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

[0238] 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.

[0239] Technical data sheet states a drop melting point according to ASTM D-127 of 96? C. Technical data sheet states a viscosity at 99? C. of 12 pcs (120 mPas).

[0240] 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: Dow PG 7008

[0241] 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.

[0242] Technical data sheet states a density at 23? C. according to ASTM D-792 of 0.918 g/cm.sup.3.

[0243] Technical data sheet states a melting temperature (DSC) of 106? C.

[0244] Technical data sheet states a vicat softening temperature according to ISO 306/A of 89.0? C.

[0245] Technical data sheet states a melt index (190? C./2.16 kg) according to ISO 1133 of 7.7 g/10 min.

[0246] 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-4: Luwax AL-3

[0247] 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.2CH.sub.2-].sub.n-H). Some physical-chemical properties are measured and depicted in table B-1.

[0248] Technical data sheet states a density at 23? C. according to DIN 53479 and ASTM D-792 of 0.91-0.925 g/cm.sup.3.

[0249] Technical data sheet states a drop point (Ubbelohde) according to DIN 51801 and ASTM D3954 of 101-112? C.

[0250] Technical data sheet states a melting point (DSC) according to DIN 51007 and ASTM D-3418 of 102-108? C.

[0251] Technical data sheet states a melt viscosity at 120? C. according to DIN 51562 and ASTM D2162 of 135-240 mm.sup.2/s.

[0252] Sieve analysis of the material in the technical form powder is measured and depicted in table B2. A bulk density of 495 g/L is measured. The material in its technical form is employed for compaction.

SM-PA-5: Licocene PP 1502

[0253] Licocene PP 1502 (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.

[0254] Technical data sheet states a density at 23? C. according to ISO 1183 of 0.87 g/cm.sup.3.

[0255] Technical data sheet states a drop point according to ASTM D 3954 of 83-90? C.

[0256] Technical data sheet states a viscosity at 170? C. according to DIN 53019 of 1500-2100 mPas.

[0257] Sieve analysis of the material in the technical form fine grain is measured and depicted in table B-2. A bulk density of 374 g/L is measured. The material in its technical form fine grain is employed for compaction.

SM-PA-6: Pluriol E3350 Prill

[0258] Pluriol E 3350 (TM, commercially available from BASF Pharma Solutions, obtained in the form of solid prills) is a cGMP Pharmaceutical Grade polyethylene glycol (CAS-No. 25322-68-3) with a mean molecular weight of 3350 that forms anhydrous, hydrophilic ointments in combination with low molecular weight PEGs. Some physical-chemical properties are measured and depicted in table B-1.

[0259] Safety data sheet states a freezing point of 59? C. at 1.013 hPa.

[0260] Safety data sheet states a dynamic viscosity of 76-110 mPas at 99? C.

[0261] Safety data sheet states a bulk density of 0.61-0.65 g/mL.

[0262] Sieve analysis of the material in the technical form prills is measured and depicted in table B-2. A bulk density of 650 g/L is measured. The material in its technical form prills is employed for compaction.

SM-PA-7: GMS 90

[0263] GMS 90 respectively Glyceryl-Monostearate 90-95 (glyceryl monostearate as INCI name, commercially available from Faci SPA, CAS-No. 91052-47-0, obtained in the technical form of a powder) is a mixture of mono-, di- and triglycerides of commercial stearic acid, i.e. containing mainly C18 fatty acid and few C16 fatty acid, which contains around 97% monoglycerides. It is also identified as 1,2,3-propanetriol monoester of octadecanoic acid (CAS-No. 31566-31-1). Depicted below is 2,3-dihydroxypropyl octadecanoate

##STR00005##

[0264] Some physical-chemical properties are measured and depicted in table B-1.

[0265] Safety data sheet states a melting point of 54-70? C.

[0266] Safety data sheet states a density of 0.95-0.96 g/cm.sup.3 at 70? C.

[0267] Sieve analysis of the material in the technical form powder is measured and depicted in table B-2. A bulk density of 590 g/L is measured. The material in its technical form powder 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 Dow PG 25-116 106 117 30176 367733 12.2 7008 SM-PA-4 Luwax 24-112 105 127 3128 7613 2.43 AL-3 SM-PA-5 Licocene 45-95 73 13 16356 39302 2.40 PP 1502 SM-PA-6 Pluriol 41-75 60 166 not not not E3350 measured measured measured Prill SM-PA-7 GMS 90 55-76 72 178 not not not measured measured measured

TABLE-US-00002 TABLE B-2 sieve analysis Q3 10% Q3 50% Q3 90% starting material [mm] [mm] [mm] SM-PA-1 0.414 0.836 1.583 SM-PA-2 (ground) 0.324 0.710 1.538 SM-PA-3 (ground) 0.225 0.484 1.091 SM-PA-4 0.302 0.740 1.521 SM-PA-5 0.482 0.874 1.278 SM-PA-6 0.132 0.280 0.556 SM-PA-7 0.164 0.316 0.547

C) Preparation of Mixtures for Compaction

[0268] Mixtures for compaction consisting of polymer stabilizers and a processing aid are prepared by blending the starting materials as depicted in table C-11 in a 100-L MTI blender for 5 minutes at room temperature.

TABLE-US-00003 TABLE C-11 mixtures for compaction polymer amount processing amount physical mixture-No. stabilizer [%] aid [%] form .sup.c) C-M-11 .sup.b) SM-PS-1 50.0 none powder SM-PS-2 50.0 C-M-12 .sup.b) SM-PS-1 47.5 SM-PA-1 5 powder SM-PS-2 47.5 C-M-13 .sup.b) SM-PS-1 46.0 SM-PA-1 8 powder SM-PS-2 46.0 C-M-14 .sup.a) SM-PS-1 46.0 SM-PA-5 8 powder SM-PS-2 46.0 C-M-15 .sup.b) SM-PS-1 46.0 SM-PA-2 8 powder SM-PS-2 46.0 C-M-16 .sup.b) SM-PS-1 46.0 SM-PA-3 8 powder SM-PS-2 46.0 C-M-17 .sup.b) SM-PS-1 46.0 SM-PA-4 8 powder SM-PS-2 46.0 C-M-18 .sup.b) SM-PS-1 46.0 SM-PA-6 8 powder SM-PS-2 46.0 C-M-19 .sup.b) SM-PS-1 46.0 SM-PA-7 8 powder SM-PS-2 46.0 Food notes: .sup.a) inventive .sup.b) comparative .sup.c) at room temperature and atmospheric pressure d) Flakes by roll compaction

[0269] For example D-11-1, the mixture for compaction C-M-11 is press-agglomerated via a roll compaction process to obtain flakes for comparison. The polymer stabilizer mixtures 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-11-1). A Norner attrition test is conducted for the flakes of D-11-1 and the result is depicted in table E-11. A pictures of the flakes obtained at examples D-11-1 is depicted at FIG. 11.

E) Pellets by Compaction with a Ring Die Pellet Mill

[0270] A ring die pellet mill, i.e. a Muench Pelletizer RMP 250, is used for compaction trials of materials as stated in tables E-11. A Muench ring die pellet mill is depicted for example in the article Produktgestaltung ?ber 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. 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-11. 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 1 m/s at the inner surface of the ring die, i.e. at 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-11 states whether pellets are obtained and thus also whether strands are formed. 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 contactless the emitted IR irradiation and stated in table E-11 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 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-11. 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-11. Further characterizations of the obtained pellets are depicted in table E-12. Pictures of the pellets obtained at examples E-11-2 to E-11-9 are depicted at FIG. 12 to FIG. 19.

TABLE-US-00004 TABLE E-11 ring die pellet mill compactions and attrition test results surface material nozzle temperature removed Norner example for composition size .sup.c) of the pellet fines test No. compaction [wt. %] [mm] [? C.] pellets [%] [%] D-11-1 .sup.b),d) C-M-11 SM-PS-1 (50) roll close to flakes 98 SM-PS-2 (50) compaction .sup.e) room temperature E-11-2 .sup.b) C-M-12 SM-PS-1 (47.5) 3 ? 15 58 yes 5 86 SM-PS-2 (47.5) SM-PA-1 (5) E-11-3 .sup.b) C-M-13 SM-PS-1 (46) 3 ? 15 63 yes 6 56 SM-PS-2 (46) SM-PA-1 (8) E-11-4 .sup.a) C-M-14 SM-PS-1 (46) 3 ? 15 68 yes 3 26 SM-PS-2 (46) SM-PA-5 (8) E-11-5 .sup.b) C-M-15 SM-PS-1 (46) 3 ? 15 67 yes 20 95 SM-PS-2 (46) SM-PA-2 (8) E-11-6 .sup.b) C-M-16 SM-PS-1 (46) 3 ? 15 79 yes 6 29 SM-PS-2 (46) SM-PA-3 (8) E-11-7 .sup.b) C-M-17 SM-PS-1 (46) 3 ? 15 74 yes 6 48 SM-PS-2 (46) SM-PA-4 (8) E-11-8 .sup.b) C-M-18 SM-PS-1 (46) 3 ? 15 71 yes 20 91 SM-PS-2 (46) SM-PA-6 (8) E-11-9 .sup.b) C-M-19 SM-PS-1 (46) 3 ? 15 69 yes 23 37 SM-PS-2 (46) SM-PA-7 (8) Food notes: .sup.a) inventive .sup.b) comparative .sup.c) nozzle diameter x press length .sup.d) example of a roll compaction as described at D) .sup.e) trials to compact C-M-11 have failed, i.e. a continously running compaction to obtain pellets could not be achieved

From the Results of the Table E-11:

[0271] mixture for compaction C-M-11, which is without a processing aid, could not be pelletized and the Norner test result for attrition of the flakes from example D-11-1 is not good; [0272] examples E-11-2, E-11-3, E-11-4 and E-11-5 comprise a propylene-ethylene copolymer wax, but the specific propylene-ethylene copolymer wax of SM-PA-5 provides the best Norner test result for attrition; [0273] example E-11-6 comprises the low density polyethylene SM-PA-3, but the Norner test result for attrition is not as good as the one for the specific propylene-ethylene copolymer wax of SMPA-5 at example E-11-4; [0274] example E-11-7 comprises the polyethylene wax SM-PA-4, but the Norner test result for attrition is not as good as the one for the specific propylene-ethylene copolymer wax of SM-PA-5 at example E-11-4; [0275] example E-11-8 comprises the polyethylene glycol SM-PA-6, but the Norner test result for attrition is not good despite of obtaining pellets as such; [0276] example E-11-9 comprises the glyceryl monosterate SM-PA-7, but the Norner test result for attrition is not as good as the one for the specific propylene-ethylene copolymer wax of SM-PA5 at example E-11-4.

TABLE-US-00005 TABLE E-12 pellet characterization average average material pellet pellet pellet Norner example for composition diameter .sup.c) length .sup.d) weight picture test .sup.e) No. compaction [wt. %] [mm] [mm] [mg] at FIG. [%] D-11-1 .sup.b) C-M-11 SM-PS-1 (50) flakes 11 98 SM-PS-2 (50) E-11-2 .sup.b) C-M-12 SM-PS-1 (47.5) 3 4.6 31 12 86 SM-PS-2 (47.5) SM-PA-1 (5) E-11-3 .sup.b) C-M-13 SM-PS-1 (46) 3 4.1 28 13 56 SM-PS-2 (46) SM-PA-1 (8) E-11-4 .sup.a) C-M-14 SM-PS-1 (46) 3 5.0 33 14 26 SM-PS-2 (46) SM-PA-5 (8) E-11-5 .sup.b) C-M-15 SM-PS-1 (46) 3 4.6 31 15 95 SM-PS-2 (46) SM-PA-2 (8) E-11-6 .sup.b) C-M-16 SM-PS-1 (46) 3 3.7 25 16 29 SM-PS-2 (46) SM-PA-3 (8) E-11-7 .sup.b) C-M-17 SM-PS-1 (46) 3 5.2 35 17 48 SM-PS-2 (46) SM-PA-4 (8) E-11-8 .sup.b) C-M-18 SM-PS-1 (46) 3 4.9 33 18 91 SM-PS-2 (46) SM-PA-6 (8) E-11-9 .sup.b) C-M-19 SM-PS-1 (46) 3 4.9 33 19 37 SM-PS-2 (46) SM-PA-7 (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-11 depicted again .sup.f) example of roll compaction as described at D)

From the Results of the Table E-12:

[0277] examples E-11-2 to E-11-9 show no big differences in average pellet weight and the average pellet weight is here not a reliable indicator for a beneficial Norner test result for attrition; [0278] the pictures at FIGS. 12 to 19 show no big differences in pellets appearances and the appearance of pellets is here not a reliable indicator for a beneficial Nomer test result for attrition.