Method for producing pellets in a pellet making machine, pellets, and use of pellets

Abstract

A method for producing pellets in a pelletizer, the method comprising: (a) pressing a compression mixture with a roller through a nozzle to obtain strands; and (b) breaking the strands to obtain pellets, the compression mixture comprising: (i) 87 to 97 wt. % of a polymer stabilizer that is tris(2,4-ditert-butylphenyl) phosphite (CAS No. 31570-04-4); and (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa. The pellets are useful for dust-free handling of the polymer stabilizer in the production of stabilized polymers. Also disclosed is a method for stabilizing a polymer that is a polyolefin, polystyrene, or a mixture thereof, the method comprising introducing pellets into the polymer.

Description

[Technical field]

[0001] The present invention relates to a method for producing pellets, comprising pressing a compression mixture comprising a polymeric stabilizer, tris(2,4-ditert-butylphenyl)phosphite, and a processing aid through the nozzle of a pellet mill to obtain strands, and breaking the strands to obtain pellets. A further embodiment is a pellet comprising a polymeric stabilizer and a processing aid. A further embodiment is the use of the pellets for dust-free handling of the components of the pellets in the production of a stabilized polymer. A further embodiment is a method for producing a stabilized polymer, comprising incorporating the pellets in a polymer, which is a polyolefin, polystyrene, or a mixture thereof, to obtain a stabilized polymer. A further embodiment is a compression mixture. [Background technology]

[0002] Organic polymers used as building materials or as part of articles for construction are susceptible to degradation by oxidation, heat or light. During the processing of polymers, there is short-term degradation that occurs, for example, when the polymer resulting from the polymer synthesis is mechanically transformed into a desired final article or intermediate article. The intermediate article is often a work-in-progress and is particularly useful for incorporating desirable additives into the polymer resulting from the polymer synthesis. Short-term degradation is often characterized by relatively short exposure to relatively high process temperatures, for example, above 80°C to 330°C, often in conjunction with mechanical pressure.

[0003] It has long been known to incorporate polymeric stabilizers into organic polymers for stabilization against oxidation, heat or light degradation. The incorporation of the polymeric stabilizer is typically carried out during the processing of the polymer for thermoplastic polymers, where the heated polymer has a reduced viscosity or is close to a liquid state, which aids in the uniform distribution of the polymeric stabilizer in the polymer. The polymeric stabilizer is very often a solid at room temperature and is obtained in powder form from its synthesis. Practical problems arise during the actual incorporation of the polymeric stabilizer in powder form. The manipulation of powders is easily prone to generate dust. Dust is a significant problem in terms of the occupational health of workers in manufacturing plants, in terms of plant safety (e.g. dust explosions), and in terms of plant cleanliness (e.g. dust contamination of plant equipment). Furthermore, the incorporation of powders into polymers is typically not carried out in a batch manner. Instead, the continuous addition of powders to the polymer is processed in a continuous manner, for example in an extruder, in an amount typically less than 0.5% by weight of the polymer, although at a particular moment the amount actually incorporated is subject to fluctuations. Thus, although a large overall amount of polymer will then statistically contain the same amount of polymeric stabilizer, this is not necessarily true for a single unit of the total amount of polymer.

[0004] To provide a suitable dust-free dosage form of the polymeric stabilizer, several approaches are known. One direction is to provide a suitable dust-free dosage form without the addition of additional components, i.e. components that are not required as a polymeric stabilizer. For example, the powdered form of the polymeric stabilizer is pressure-agglomerated by rotary compression to obtain flakes. Another approach is to form a pastille from the powdered form of the polymeric stabilizer by melting the polymeric stabilizer and solidifying a drop of the melt on a cooled surface. Another approach is to form pellets from the powdered form of the polymeric stabilizer by heating and kneading the polymeric stabilizer in an extruder at a temperature above the softening point of the polymeric stabilizer, extruding the heated mass through a die to form warm strands, and cutting the warm strands into pellets. Another direction is to provide a suitable dust-free dosage form by adding additional components, i.e. components that are not required as a polymeric stabilizer. The additional component may be called a compression aid, binder or processing aid, and in the case of a polymeric additional component, may also be called a masterbatch polymer or carrier polymer, and typically acts as a kind of hot melt glue (adhesive) for each particle of the polymeric stabilizer powder. Whether the polymeric stabilizer itself melts at least in large part depends on the temperature applied and the chemical nature of the additional component relative to the polymeric stabilizer, in particular whether there is a certain mutual solubility. The addition of the additional component into the polymeric stabilizer dosage form has advantages. In particular, the polymeric stabilizer dosage form may be obtained initially dust-free by simply sieving the respective screening dust at the end of production. However, the wear resistance of the initially dust-free dosage form is one property that is relevant in terms of the transport of the dosage form and the associated formation of dust.

[0005] Tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4) is a polymer stabilizer that functions as a short-term processing stabilizer. It has a melting range of 180-183°C and is found, for example, in Irgafos 168 (trademark, available from BASF SE).

[0006] Japanese Patent Application Laid-Open No. 06-254845 relates to a stabilizer having powder-preventing and dispersing properties, which is produced by mixing a powder of a heat stabilizer and a powder of an organic compounding agent having a melting point or softening point lower than that of the heat stabilizer in a specified ratio, supplying the mixture to a ring-shaped perforated plate, and extruding the mixture from the plate into granules by a rotating roller.

[0007] US Patent No. 5,846,656 relates to a stabilization system for stabilizing polymeric materials against UV and thermo-oxidative degradation, the stabilization system being in the form of pellets. The pellets are formed from a substantially dry homogeneous mixture of at least one stabilizer and an agent that prevents melting of the stabilizer. The stabilizer compound constitutes about 50% to about 98% by weight of the mixture. The stabilizer is an antioxidant, such as a phosphite and a hindered phenol or hindered amine UV light stabilizer, or a combination thereof. The melting inhibitor can be a compound derived from a fatty acid or a fatty alcohol, a fatty acid or a fatty alcohol, or a combination of a plurality of fatty acids or fatty alcohols, constituting about 3% to 10% of the homogeneous mixture. The fatty acids, fatty alcohols, and compounds derived therefrom preferably have a low melting point in the range of 50 to 100°C, preferably in the range of 50 to about 80°C. Alternatively, the melting inhibitor can be a lubricant having a small particle size, constituting about 2 to 50% by weight of the homogeneous mixture.

[0008] No. 6,596,198 relates to a pelletized stabilizer additive system and a method for producing the system with good pellet yield, preferably at least about 90% by weight. The stabilizer additive system includes at least a stabilizer and a processing aid, preferably a release agent. The processing aid has a lower melting temperature than the stabilizer. The stabilizer constitutes less than 50% by weight of the total weight of the stabilizer and release agent combined.

[0009] WO 2008-033410 relates to a high concentration pelletized additive concentrate or polymer stabilizer or blend and their preparation, which can be used to enhance stability in various polymerization processes. The pelletized additive concentrate comprises at least 10% by weight of carrier polymer, and in the examples is obtained by heating the additive mixture together with the carrier polymer in an extruder at a temperature above the melting temperature of the carrier polymer but below the melting temperature of the main additive, and then chopping the warm strand into pellets. Example 4 results in pellets with a content of tris(2,4-ditert-butylphenyl)phosphite of 48% by weight, in pellets with a total content of 70% by weight of polymer stabilizer and 30% by weight of polyethylene as carrier polymer. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication No. 06-254845 [Patent Document 2] U.S. Patent No. 5,846,656 [Patent Document 3] U.S. Patent No. 6,596,198 [Patent Document 4] International Publication No. 2008-033410 Summary of the Invention [Problem to be solved by the invention]

[0011] There is still a need for further solid dosage forms of the polymeric stabilizer, which is tris(2,4-ditert-butylphenyl) phosphite, originally in powder form as starting material. In a first aspect, the manufacture of each dosage form of the dosage form unit should ideally be carried out without warming the polymeric stabilizer, or at least should minimize warming. First, this saves process energy that would be required to warm the polymeric stabilizer, either by direct or indirect heating, i.e. mechanical pressure is converted into thermal energy, which results in a clear increase in the temperature of the polymeric stabilizer being processed. Second, this also avoids unnecessary exposure of the polymeric stabilizer to high temperatures. Unnecessary exposure should generally be avoided, and individual polymeric stabilizers may also undergo phase transitions, for example, a originally crystalline material transitioning to a viscous state. Furthermore, the manufacture of the dosage form should be carried out without the generation of defective products, i.e. a high percentage of the utilized polymeric stabilizer starting material should be processed into the dosage form in one run. In other words, the amount of rejects generated should be low even if it is in a form that can be directly reused again as starting material. An example of rejects removal is the sieving of the desired dosage form to obtain a dust-free dosage form initially. In the second embodiment, the dosage form of the polymer stabilizer should remain stable during storage and transportation after its production. In particular, the initial dust-free dosage form may generate fine dust particles due to mutual abrasion of the dosage form units during exposure to vibration, for example during filling into bags, during transportation of filled bags, or during feeding operations of the dosage form units for incorporation into the polymer to be stabilized (to be stabilized), respectively. Therefore, a certain level of abrasion resistance of the dosage form is desirable. In the third embodiment, the dosage form units should ideally not be too diverse in their shape and weight, as this allows for more accurate feeding of the dosage form units during incorporation into the polymer to be stabilized. The result of more accurate feeding is that the concentration of the polymer stabilizer in the stabilized polymer does not fluctuate too much, especially during continuous addition into the polymer to be stabilized.In other words, the local concentration of the polymeric stabilizer in a particular part of the stabilized polymer does not show much deviation from the average concentration of the polymeric stabilizer in the entire stabilized polymer.When the supply of the dosage form unit occurs in one step in the incorporation into the stabilized polymer, the polymer itself still exists as a solid unit, for example, pellets, and thus the dosage form unit is advantageously relatively similar in shape and weight to the solid unit of the polymer.This dislikes the mixture of the dosage form unit and the solid unit of the stabilized polymer separating while being transported as a mixture.An example of such a transport is the pumping of the mixture of the stabilized polymer and the polymeric stabilizer from a storage facility to a device for incorporation into the polymer, for example, an extruder.In the fourth embodiment, the dosage form of the polymeric stabilizer should contain a low content of auxiliary components.The auxiliary components may only be present during the manufacture of the dosage form, for example, during the addition of a solvent that is subsequently removed.The auxiliary components may be present permanently, i.e., the composition of the dosage form contains the auxiliary components that will be incorporated into the stabilized polymer. In the fifth embodiment, the stabilization of the polymer is ideally aided by the uniform distribution of individual polymer stabilizer molecules throughout the stabilized polymer. Alternatively, if the polymer stabilizer is not soluble as an individual molecule in the stabilized polymer, aggregates of individual molecules of the insoluble polymer stabilizer, or larger particles from aggregates of individual polymer stabilizer molecules, are uniformly distributed in the stabilized polymer. The potential effect of the dosage form on the distribution of the polymer stabilizer is clear by considering that initially all the polymer stabilizer molecules are concentrated in the dosage form, but then all the polymer stabilizer is ideally uniformly distributed in the stabilized polymer. The non-uniform distribution of the polymer stabilizer in the stabilized polymer may also be noticed differently from the stability of the stabilized polymer against degradation, which is reduced compared to the polymer stabilized by a more complete initial distribution, such as when the powders of the polymer and the polymer stabilizer are mixed.For example, a non-uniformly distributed polymer stabilizer in a stabilized polymer may disturb the surface properties when producing a thin polymer film from said stabilized polymer, or may cause clogging of filters or nozzles when rotary extruding the stabilized polymer. The nature of the stabilized polymer is related to the suitable polymer stabilizer. For example, polyamides change into certain solvents, such as dimethylsulfoxide, on the way to a molten state, whereas polyolefins typically change into only certain solvents, such as n-hexane or decalin, on the way to a molten state. Therefore, there is less possibility to modify the distribution of the polymer stabilizer in the polyolefin during processing of the polyolefin at a higher temperature than during processing in the polyamide. [Means for solving the problem]

[0012] 1. A method for producing pellets in a pelletizer having a roller and a die with a nozzle, the method comprising: (A) pressing the compression mixture with a roller through a nozzle to obtain a strand; and (B) Breaking the strands to obtain pellets and the compression mixture comprises (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 weight percent of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. The weight percent is based on the weight of the compression mixture. A method was found. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 shows the pellets obtained in Example E-1-1 placed on graph paper. [Diagram 2] FIG. 1 shows the pellets obtained in Example E-1-2 placed on graph paper. [Diagram 3]FIG. 1 shows the pellets obtained in Example E-1-3 placed on graph paper. [Figure 4] FIG. 1 shows the pellets obtained in Example E-1-4 placed on graph paper. [Diagram 5] FIG. 1 shows the pellets obtained in Example E-1-5 placed on graph paper. [Figure 6] FIG. 1 shows the pellets obtained in Example E-1-6 placed on graph paper. [Figure 7] FIG. 1 shows the pellets obtained in Example E-1-7 placed on graph paper. [Figure 8] FIG. 1 shows the pellets obtained in Example E-1-8 placed on graph paper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The weight percentages of components (i) and (ii) in the compression mixture are based on the weight of the compression mixture. Thus, the weight percentages of all components in the compression mixture, including components (i) and (ii), add up to 100% by weight in total. In other words, the sum of all components is 100% by weight. The sum of components (i) and (ii) is less than or equal to 100% by weight.

[0015] Polymer stabilizers serve to stabilize polymers susceptible to oxidative, thermal, or photoinduced degradation. Tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4) is shown below.

[0016] [ka]

[0017] Such substances are contained, for example, in the commercially available polymer stabilizer Irgafos 168 (trademark BASF). The substances mainly function as short-term processing stabilizers. Short-term processing stabilizers are used for short-term aging, which is often characterized by the exposure of the polymer to relatively high processing temperatures (e.g. above 80°C to 330°C) for a relatively short period of time, often in combination with mechanical stress.

[0018] Preferably, the polymeric stabilizer is in powder form. The bulk density of the powder is determined according to DIN EN ISO 17892-3. Preferably, the polymeric stabilizer is in powder form and has a bulk density of more than 300g / L and less than 900g / L, very preferably more than 350g / L and less than 600g / L, particularly more than 380g / L and less than 550g / L, very particularly more than 400g / L and less than 500g / L, as determined according to DIN EN ISO 17892-3.

[0019] The processing aid has a melting enthalpy, melting peak temperature, and melting range of less than 100 J / g at 101.32 kPa. The melting enthalpy is determined by differential scanning calorimetry (DSC) according to EN ISO 11357-3, preferably at atmospheric pressure, e.g., 101.32 kPa. The melting temperature and melting range are also determined by differential scanning calorimetry according to EN ISO 11357-3, preferably at atmospheric pressure, e.g., 101.32 kPa. Preferably, EN ISO 11357-3 at atmospheric pressure is determined by: (a) a melting rate of 10° C. / min and 30 mL / min N 2 (b) from 0°C to 200°C at 10°C / min and 30mL / min N 2 (c) from 200°C to 0°C at 10°C / min and 30mL / min N 2 The test is carried out in three successive heating cycles from 0°C to 200°C.

[0020] Preferably, the enthalpy of fusion of the processing aid is from greater than 10 J / g to less than 100 J / g at 101.32 kPa, very preferably from greater than 15 J / g to less than 85 J / g, in particular from greater than 17 J / g to less than 70 J / g, very particularly from greater than 18 J / g to less than 55 J / g, in particular from greater than 19 J / g to less than 40 J / g, very particularly from greater than 20 J / g to less than 30 J / g, and most particularly from greater than 21 J / g to less than 25 J / g.

[0021] Preferably, the melting peak temperature of the processing aid is from above 50°C to below 85°C, very preferably from above 55°C to below 83°C, in particular from above 60°C to below 81°C, very particularly from above 65°C to below 80°C, in particular from above 70°C to below 79°C, very particularly from above 73°C to below 78°C, and most particularly from above 75°C to below 77°C.

[0022] Preferably, the melting range of the processing aid is between 20°C and 100°C, very preferably between 21°C and 99°C, in particular between 22°C and 98°C, very particularly between 23°C and 97°C, especially between 24°C and 96°C.

[0023] Preferred is a method for producing pellets, wherein the processing aid has a peak melting temperature of more than 50°C and less than 85°C.

[0024] The propylene-ethylene copolymer processing aid has a weight average molecular weight (Mw), a number average molecular weight (Mn) and a polydispersity index (PD) which is the ratio of Mw to Mn. Preferably, the weight average molecular weight, the number average molecular weight and the polydispersity index are determined by gel permeation chromatography (GPC), very preferably by high temperature gel permeation chromatography (HT-GPC) according to ISO 16014-4. In gel permeation chromatography, the detector is preferably a refractive index detector (RI detector). The solvent is preferably trichlorobenzene. The column temperature is preferably 150° C. The calibration standards preferably comprise polystyrene.

[0025] Preferably, the weight average molecular weight of the processing aid which is a propylene-ethylene copolymer is more than 10,000 Da (daltons) and less than 40,000 Da, very preferably more than 12,000 Da and less than 35,000 Da, in particular more than 14,000 Da and less than 30,000 Da, very particularly more than 15,000 Da and less than 25,000 Da, in particular more than 16,000 Da and less than 20,000 Da, and very particularly more than 17,000 Da and less than 18,000 Da.

[0026] Preferably, the number average molecular weight of the processing aid which is a propylene-ethylene copolymer is more than 2000 Da and less than 10000 Da, very preferably more than 3000 Da and less than 9000 Da, in particular more than 4000 Da and less than 8000 Da, very particularly more than 5000 Da and less than 7500 Da, especially more than 6000 Da and less than 7000 Da.

[0027] Preferably, the polydispersity index of the processing aid which is a propylene-ethylene copolymer is from 1.3 to less than 7, very preferably from 1.5 to less than 5, in particular from 1.7 to less than 4, very particularly from 1.9 to less than 3.5, in particular from 2.1 to less than 3, and very particularly from 2.3 to less than 2.7.

[0028] Preferably, the propylene-ethylene copolymer processing aid has a weight average molecular weight of more than 10,000 Da and less than 40,000 Da, and a number average molecular weight of more than 2,000 Da and less than 10,000 Da, very preferably a weight average molecular weight of more than 12,000 Da and less than 35,000 Da, and a number average molecular weight of more than 3,000 Da and less than 9,000 Da, in particular a weight average molecular weight of more than 14,000 Da and less than 30,000 Da, and a number average molecular weight of more than 4,000 Da and less than 8,000 Da, very particularly a weight average molecular weight of more than 15,000 Da and less than 25,000 Da, and a number average molecular weight of more than 5,000 Da and less than 7,500 Da, in particular a weight average molecular weight of more than 16,000 Da and less than 20,000 Da, and a number average molecular weight of more than 6,000 Da and less than 7,000 Da.

[0029] Preferably, the polydispersity index of the propylene-ethylene copolymer processing aid is greater than 1.3 and less than 7, and the weight average molecular weight is greater than 10,000 Da (daltons) and less than 40,000 Da, and very preferably, the polydispersity index is greater than 1.5 and less than 5, and the weight average molecular weight is greater than 12,000 Da and less than 35,000 Da, and in particular, the polydispersity index is greater than 1.7 and less than 4, and the weight average molecular weight is greater than 14,000 Da. and less than 30,000 Da, very particularly a polydispersity index of more than 1.9 and less than 3.5 and an average molecular weight of more than 15,000 Da and less than 25,000 Da, in particular a polydispersity index of more than 2.1 and less than 3 and an average molecular weight of more than 16,000 Da and less than 20,000 Da, and very particularly a polydispersity index of more than 2.3 and less than 2.7 and an average molecular weight of more than 17,000 Da and less than 18,000 Da.

[0030] It is understood that the polydispersity index is mathematically correlated with the weight average molecular weight and the number average molecular weight. Therefore, in the following, the given polydispersity index range means that only the specific polydispersity index is intended, which can be obtained by selecting a suitable specific average molecular weight from the given average molecular weight range and selecting a suitable specific number average molecular weight from the given number average molecular weight range. Preferably, the polydispersity index of the propylene-ethylene copolymer processing aid is more than 1.3 and less than 7, the weight average molecular weight is more than 10,000 Da (Dalton) and less than 40,000 Da, and the number average molecular weight is more than 2,000 Da and less than 10,000 Da. Very preferably, the polydispersity index is more than 1.5 and less than 5, the weight average molecular weight is more than 12,000 Da and less than 35,000 Da, and the number average weight is more than 3,000 Da and less than 9,000 Da. In particular, the polydispersity index is greater than 1.7 and less than 4, the weight average molecular weight is greater than 14,000 Da and less than 30,000 Da, and the number average molecular weight is greater than 4,000 Da and less than 8,000 Da. Very particularly, the polydispersity index is greater than 1.9 and less than 3.5, the average molecular weight is greater than 15,000 Da and less than 25,000 Da, and the number average molecular weight is greater than 5,000 Da and less than 7,500 Da. In particular, the polydispersity index is greater than 2.1 and less than 3, the average molecular weight is greater than 16,000 Da and less than 20,000 Da, and the number average molecular weight is greater than 6,000 Da and less than 7,000 Da.

[0031] Preferred is a method for producing pellets, wherein the processing aid has a weight average molecular weight of more than 10,000 Da and less than 40,000 Da.

[0032] Preferably, the processing aid is in powder form. The bulk density of the powder is determined according to DIN EN ISO 17892-3. Preferably, the processing aid is in powder form and has a bulk density, determined according to DIN EN ISO 17892-3, of more than 200g / L and less than 800g / L, very preferably more than 250g / L and less than 600g / L, in particular more than 280g / L and less than 400g / L, very particularly more than 300g / L and less than 400g / L.

[0033] Preferably, the processing aid is a waxy propylene-ethylene copolymer. Preferably, the processing aid is a propylene-ethylene copolymer wax synthesized from propylene and ethylene using a metallocene catalyst. Preferably, the processing aid is a propylene-ethylene copolymer in which the long polymer chains are replaced by short chains (-CH 3 ), very preferably essentially only short chain branched, especially only short chain branched, propylene-ethylene copolymer. Preferably, the processing aid is a propylene-ethylene copolymer wax having a density of 0.85 g / cm at 23° C. according to ISO 1183. 3 Super~0.90g / cm 3 Less than 0.87 g / cm 3 Preferably, the processing aid is a propylene-ethylene copolymer wax having a dropping point according to ASTM D 3954 of more than 80° C. and less than 100° C., very preferably more than 85° C. and less than 95° C., in particular a dropping point in the range of 87° C. to 93° C. Preferably, the processing aid is a propylene-ethylene copolymer wax having a viscosity according to DIN 53019 of more than 50 mPas and less than 750 mPas at 170° C., very preferably more than 100 mPas and less than 500 mPas, in particular more than 120 mPas and 350 mPas, very particularly a viscosity in the range of 150 mPas to 250 mPas. Preferably, the processing aid is a propylene-ethylene copolymer wax, Licocene PP 1302.

[0034] Preferred is a method for producing pellets, wherein the processing aid is a waxy propylene-ethylene copolymer.

[0035] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 88-97% by weight of a polymeric stabilizer, and (ii) 3-12% by weight of a processing aid.

[0036] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 90-97% by weight of a polymeric stabilizer, and (ii) 3-10% by weight of a processing aid.

[0037] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 91-97% by weight of a polymeric stabilizer, and (ii) 3-9% by weight of a processing aid.

[0038] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 89-96 wt. % of a polymeric stabilizer, and (ii) 4-11 wt. % of a processing aid.

[0039] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 90-96% by weight of a polymeric stabilizer, and (ii) 4-10% by weight of a processing aid.

[0040] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 91-96% by weight of a polymeric stabilizer, and (ii) 4-9% by weight of a processing aid.

[0041] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 87-94 wt. % of a polymeric stabilizer, and (ii) 6-13 wt. % of a processing aid.

[0042] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 88-94 wt. % of a polymeric stabilizer, and (ii) 6-12 wt. % of a processing aid.

[0043] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 87-93 wt. % of a polymeric stabilizer, and (ii) 7-13 wt. % of a processing aid.

[0044] Preferred is a method for producing pellets, wherein the compression mixture comprises (i) 88-93 wt. % of a polymeric stabilizer, and (ii) 7-12 wt. % of a processing aid.

[0045] If additional components other than the polymer and the processing aid are contained in the compression mixture, the additional components are contained only in relatively small amounts, i.e., 10% by weight or less (=0-10% by weight). The additional components also include mixtures of additional components. Thus, the mixtures of additional components are contained only in relatively small amounts, i.e., 10% by weight or less (=0-10% by weight). The additional components are, for example, another polymer stabilizer, another processing aid or a filler. The other polymer stabilizer is, for example, a phenolic antioxidant, a UV absorber, a hindered amine light stabilizer, a metal deactivator, a phosphite other than the polymer stabilizer, a phosphonite, a hydroxylamine or an amine N-oxide, a thiosynergist, an acid scavenger or a peroxide scavenger. The other processing aid is, for example, oleamide, erucamide, behenamide or glyceryl monostearate. The filler is, for example, silica, talc or wollastonite. Preferably, the additional component has a light absorption maximum at a wavelength of less than 380 nm, very preferably less than 350 nm, in particular less than 300 nm, very particularly less than 280 nm, especially less than 260 nm, and very particularly no light absorption maximum above 250 nm.

[0046] The additional component is preferably solid at 23° C. and 101.32 KPa. Preferably, the additional component is in powder form. The bulk density of the powder is determined according to DIN EN ISO 17892-3. Highly preferably, the additional component is in powder form and has a bulk density of more than 200 g / L and less than 950 g / L.

[0047] Preferably, the additional component is present in the compression mixture in an amount of 9% by weight or less (=0-9% by weight), very preferably in an amount of 8% by weight or less (=0-8% by weight), in particular in an amount of 7% by weight or less (=0-7% by weight), very particularly in an amount of 6% by weight or less (=0-6% by weight), in particular in an amount of 5% by weight or less (=0-5% by weight), very particularly in an amount of 3% by weight or less (=0-3% by weight), most particularly in an amount of 1% by weight or less (=0-1% by weight), and very most particularly no additional component is present in the compression mixture.

[0048] Preferred is a method for producing pellets in a pelletizer equipped with rollers and a die with a nozzle, the method comprising: (A) pressing the compression mixture with a roller through a nozzle to obtain a strand; and (B) Breaking the strands to obtain pellets Including, The compression mixture is (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 10% by weight or less of an additional component different from components (i) and (ii). Including, The sum of components (i), (ii) and (iii) is 100% by weight or less; This is the method.

[0049] Preferred is a method for producing pellets in a pelletizer equipped with rollers and a die with a nozzle, the method comprising: (A) pressing the compression mixture with a roller through a nozzle to obtain a strand; and (B) Breaking the strands to obtain pellets Including, The compression mixture is (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 0 to 10% by weight of an additional component different from components (i) and (ii) It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0050] Preferred is the method for producing pellets, wherein the mixture for compression contains 0-3 wt. % of (iii) the additional component.

[0051] Preferred is a method for producing pellets, the compression mixture comprising: (i) 88 to 97% by weight of a polymeric stabilizer; (ii) 3 to 12 weight percent of a processing aid, and (iii) Additional components: 0 to 9% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0052] Preferred is a method for producing pellets, the compression mixture comprising: (i) 90 to 97% by weight of a polymeric stabilizer; (ii) 3 to 10% by weight of a processing aid, and (iii) 0 to 7% by weight of an additional component; The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0053] Preferred is a method for producing pellets, the compression mixture comprising: (i) 91 to 97% by weight of a polymeric stabilizer; (ii) 3 to 9 weight percent of a processing aid, and (iii) Additional components: 0 to 6% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0054] Preferred is a method for producing pellets, the compression mixture comprising: (i) 89 to 96% by weight of a polymeric stabilizer; (ii) 4 to 11 weight percent of a processing aid, and (iii) Additional components: 0 to 7% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0055] Preferred is a method for producing pellets, the compression mixture comprising: (i) 90 to 96% by weight of a polymeric stabilizer; (ii) 4 to 10% by weight of a processing aid, and (iii) Additional components: 0 to 6% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0056] Preferred is a method for producing pellets, the compression mixture comprising: (i) 91 to 96% by weight of a polymeric stabilizer; (ii) 4 to 9% by weight of a processing aid, and (iii) Additional components: 0 to 5% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0057] Preferred is a method for producing pellets, the compression mixture comprising: (i) 87 to 94% by weight of a polymeric stabilizer; (ii) 6 to 13% by weight of a processing aid, and (iii) Additional components: 0 to 7% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0058] Preferred is a method for producing pellets, the compression mixture comprising: (i) 88 to 94% by weight of a polymeric stabilizer; (ii) 6 to 12% by weight of a processing aid, and (iii) Additional components: 0 to 6% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0059] Preferred is a method for producing pellets, the compression mixture comprising: (i) 87 to 93% by weight of a polymeric stabilizer; (ii) 7 to 13 wt. % of a processing aid, and (iii) Additional components: 0 to 6% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0060] Preferred is a method for producing pellets, the compression mixture comprising: (i) 88 to 93% by weight of a polymeric stabilizer; (ii) 7 to 12 wt. % of a processing aid, and (iii) Additional components: 0 to 5% by weight It consists of: The sum of components (i), (ii) and (iii) is 100% by weight; This is the method.

[0061] The compression mixture is preferably solid at 23° C. and 101.32 KPa. Very preferably, the compression mixture is powdered. Preferably, the powdered compression mixture is obtained by physical mixing of the powdered polymeric stabilizer and the powdered processing aid, and optionally additional components in powder form. The physical mixing does not include complete melting of the polymeric stabilizer or processing aid, and does not include dissolving the polymeric stabilizer or processing stabilizer in a solvent, followed by partial or total evaporation of the solvent. The powdered solid particles of components (i), (ii) and optionally (iii) are uniformly distributed in the compression mixture. The physical mixing can be carried out batchwise or continuously.

[0062] The mixture for compression is the feed material in the process of producing pellets in a pelletizer. The mixture for compression is usually continuously fed by gravity into the section of the pelletizer with the nozzle die and rollers. If the temperature of the mixture for compression at the time of feeding into the section of the pelletizer with the nozzle die and rollers is too high, a pasty mass will form in the roller area, which may lead to failure of the production process. The temperature of the mixture for compression at the time of feeding is preferably below 40° C., very preferably feeding is performed at room temperature. The rollers pre-compact and degas the feed material and press (compact) it through the nozzle. A cylindrical strand is formed. More precisely, the mixture for compression as the feed material is further compressed in the feed zone of the nozzle, which may be conical, and in the long, usually cylindrically formed channel of the nozzle, it starts to heat up and sinter due to friction of the nozzle surface. The relevant surface of the nozzle is the channel surface of the nozzle along the smallest diameter of the channel, which is usually cylindrical. The smallest diameter of the nozzle is defined here as the nozzle diameter. The pressing length is defined here as the distance at which the smallest diameter of the cylindrical channel fits. The cylindrical channel of the nozzle may expand next to the pressing length, but the expanded part of the cylindrical channel does not contribute to an increase in friction with the feed material. The nozzle diameter and the pressing length are parameters that affect the degree of sintering. Breaking the strands to obtain pellets is carried out, for example, with a cutting knife as a crushing device at a regulated distance from the outside of the die. The cutting with the cutting knife breaks the strands respectively into pellets of various lengths, which are usually 1 to 3 times the nozzle diameter. The pellets are then cooled and can be sieved, for example, on a 1.6 mm sieve, which can be done, for example, with a vibrating sieve. The sieved fine fraction, consisting essentially of the mixture for pressing in a partially compressed form, can be reused directly as feed material or after grinding. A more detailed explanation is given in the experimental part in section E). It should be noted that step (A) may be performed more than once before step (B), i.e. more than one pressing may be performed before the formed strands are broken.The parameter for this is the distance between the end of the press length and the crushing device, for example a cutting knife.

[0063] Prior to step (A), the mixture for compression is fed to a section of the pelletizer that includes a die with a nozzle and rollers. The mixture for compression is preferably fed to the pelletizer in powder form. Feeding is preferably by gravity.

[0064] Preferred is a method for producing pellets, comprising the steps of: (Pre-A) Feeding the mixture for compression to a pelletizer, the mixture for compression being in powder form Including, Step (pre-A) occurs before step (A), This is the method.

[0065] The surface temperature of the formed strands increases after leaving the nozzle due to the friction generated relative to the ambient temperature. The surface temperature of the strands is determined, for example, by measurement of infrared radiation. Preferably, the surface temperature of the strands is above 50°C and below 110°C, very preferably above 55°C and below 105°C, in particular above 60°C and below 103°C, very particularly above 62°C and below 101°C.

[0066] Preferred is a method for producing pellets, wherein the strands have a surface temperature of more than 50°C and less than 110°C.

[0067] The pelletizer is preferably a ring die pelletizer or a flat die pelletizer. In the gear pelletizer, two gears act as rollers and a spur gear arrangement between them forms the equivalent of a nozzle and a die. This allows the compression mixture to be compressed into tablets.

[0068] Preferred is a method of producing pellets, wherein the pelletizer is a ring die pelletizer, the die having a ring geometry with an inner side and an outer side, and the nozzle corresponds to the passage from the inner side to the outer side, or the pelletizer is a flat die pelletizer, the die having a flat plate geometry with an upper side and a lower side, and the nozzle corresponds to the passage from the upper side to the lower side.

[0069] Preferred are methods for producing pellets, in which in a ring die pelletizer the ring rotates and the rollers are provided with a fixed shaft, and in a flat die pelletizer the die is fixed and the rollers are provided with a rotating shaft.

[0070] The main factor of mechanical energy input is the ratio of the press length of the nozzle to the nozzle diameter of the nozzle. For example, the surface temperature is influenced by the press length and the nozzle diameter of the selected nozzle. Preferably, the ratio of the press length to the nozzle diameter is 2-8, very preferably 3-7, in particular 4-6, and very particularly 5.

[0071] Preferred is a method of producing pellets, wherein the nozzle has a nozzle diameter and a press length, and the ratio of the press length to the nozzle diameter is 2-8.

[0072] The roller, preferably two or more rollers, very preferably two or three rollers, is usually driven by friction between the roller, the mixture to be compressed, and the die. If the surface of the roller is smooth, the roller may slip. By making the roller surface corrugated, the degree of slippage that is too high, which may lead to failure of the manufacturing process, is reduced.

[0073] Preferred is a method for producing pellets, wherein the roller surface is corrugated.

[0074] In a ring die pelletizer, another factor in the mechanical energy input is the rotational speed, which corresponds to the number of revolutions of the ring die.

[0075] Preferred is the method of producing pellets, wherein the pelletizer is a ring die pelletizer.

[0076] The number of dies of the pelleting machine is determined by the structural design and engineering considerations of the pelleting machine. Preferably, the pelleting machine comprises one die. The number of rollers of the pelleting machine is determined by the structural design and engineering considerations of the pelleting machine. The higher the number of rollers, the more frequently steps (A) and (B) can be performed in the pelleting machine over a certain period of time, in the case of a die comprising two or more nozzles arranged opposite each other in the die. The pelleting machine preferably comprises two or more rollers, very preferably two, three or four rollers, in particular two or three rollers, very particularly two rollers. The number of nozzles of the die is determined by the structural design and engineering considerations of the pelleting machine. A higher number of nozzles of the die allows step (A) to be performed in parallel or later in the individual nozzles, forming two or more strands in parallel. Here, "later" means that step (A) is performed in another nozzle before step (A) is first repeated again in the first nozzle. Step (B) is then performed in principle in parallel. That is, the breaking of two or more strands is carried out in parallel as a rule. Thus, in principle, two or more pellets are obtained in parallel. Thus, the production number of pellets in a certain period of time is significantly increased. The die of the pellet making machine is preferably equipped with two or more nozzles, very preferably 48-20000, in particular 96-16000, very particularly 360-14000, in particular 720-12000, very particularly 1440-11000, most particularly 3600-10000 nozzles.

[0077] Preferred is a method for producing pellets, wherein the pelletizer comprises two rollers.

[0078] Preferred is a method of producing pellets, wherein the pelletizer comprises a ring having two or more nozzles.

[0079] Preferred is a method for producing pellets, wherein the pelletizer comprises one ring.

[0080] Preferred is a method of producing pellets, wherein the pelletizer comprises two or more rollers and the die comprises two or more nozzles.

[0081] Preferred is a method of making pellets, where the pelletizer comprises a die, two or more rollers, and the die comprises two or more nozzles.

[0082] Preferred is a method of producing pellets, wherein the pelletizer comprises a die, two or more rollers, the die comprises two or more nozzles, and step (A) is performed with a first of the two or more nozzles and simultaneously or subsequently (but before step (A) is performed again with the first of the two or more nozzles) with a second of the two or more nozzles.

[0083] The pellets that can be obtained from the compression method are: (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4), and (ii) 3 to 13 weight percent of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. and weight percent is based on the weight of the pellet.

[0084] The weight percentages of components (i) and (ii) in the pellets are based on the weight of the pellets. Thus, the weight percentages of all components contained in the pellets, including components (i) and (ii), add up to 100% by weight in total. In other words, the sum of all components is 100% by weight. The sum of components (i) and (ii) is less than or equal to 100% by weight.

[0085] Preferably, the pellets are (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 10% by weight or less of an additional component different from components (i) and (ii). wherein the sum of components (i), (ii) and (iii) is not more than 100% by weight.

[0086] Preferably, the pellets are (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 0 to 10% by weight of an additional component different from components (i) and (ii) The total of components (i), (ii) and (iii) is 100% by weight.

[0087] The pellets preferably have the shape of a round bar. The shape of the round bar is ideally cylindrical, but in the case of the pellets, the two bottom regions of the cylinder are not necessarily flat and parallel to each other, especially not flat and parallel to each other. This is due to the breaking of the strands, which are the strands of step (B), which contains more breakage elements than the case of hot cutting with a knife of strands uniformly heated to a temperature of more than 110 ° C. The round bar has a diameter of a circle. Preferably, the diameter of the circle of the round bar is between 2 mm and 4 mm, very preferably 3 mm. The length of the pellet is understood here as the longest distance on the axis of the pellet, defined by the direction of strand formation in the nozzle, i.e. by having the same distance on average to a point on the pellet surface, except for a point on the pellet surface that is generated by breaking the strands. In the case of a round bar, the axis of the pellet is the axis of rotation of the round bar. The pellets preferably have a length of 1 to 3 times the diameter of the circle. A pellet has a specific length value by itself, but multiple pellets may have an average length of the pellets. This is caused by step (B), which is performed by cutting with the breaking element. Under the distance of the breaking device in step (B), the design of the nozzle and the nozzle channel plays a role. One option is that the press length of the nozzle is followed by a section with a diameter larger than the diameter of the nozzle. The nozzle thus comprises a channel with a press length section and an extension section following the press length section. The extension section allows the desired thickness of the die to be larger than the press length of the nozzle. For reasons of the mechanical strength of the die, a certain thickness of the die may be desirable, for example to avoid breakage of the die.

[0088] A possible step (C) is to sieve the pellets from step (B), for example through a 1.6 mm sieve, to remove fines resulting from the process by which the pellets are produced, for example from step (B).

[0089] A possible step (D) is to cool the pellets, for example so that their temperature is similar to the ambient temperature of the pelletizer, which is preferably room temperature, very preferably 23° C. This cooling may have already been carried out partially or completely during possible step (C). The cooling can be supported by an air flow.

[0090] The above definitions and preferences for the method of producing pellets in a pelletizer, the compression mixture, and the pellets are described with respect to the method of producing pellets in a pelletizer. These definitions and preferences also apply to the further embodiments of the present invention.

[0091] A further embodiment of the invention is a compression mix comprising: (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4); and (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion of less than 100 J / g at 101.32 kPa. The weight percent is based on the weight of the compression mixture. It is a compression mixture.

[0092] The weight percentages of components (i) and (ii) in the compression mixture are based on the weight of the compression mixture. Thus, the weight percentages of all components in the compression mixture, including components (i) and (ii), add up to 100% by weight in total. In other words, the sum of all components is 100% by weight. The sum of components (i) and (ii) is less than or equal to 100% by weight.

[0093] Preferably, the compression mixture comprises: (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion at 101.32 kPa of less than 100 J / g; and (iii) 10% by weight or less of an additional component different from components (i) and (ii). wherein the sum of components (i), (ii) and (iii) is not more than 100% by weight.

[0094] Preferably, the compression mixture comprises: (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion at 101.32 kPa of less than 100 J / g; and (iii) 0 to 10% by weight of an additional component different from components (i) and (ii) The total of components (i), (ii) and (iii) is 100% by weight.

[0095] The mixture for compression is preferably in powder form.

[0096] A further embodiment of the present invention is a pellet comprising: (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4), and (ii) 3 to 13 weight percent of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. Wt% is based on the weight of the pellet; It is a pellet.

[0097] The weight percentages of components (i) and (ii) in the pellets are based on the weight of the pellets. Thus, the weight percentages of all components contained in the pellets, including components (i) and (ii), add up to 100% by weight in total. In other words, the sum of all components is 100% by weight. The sum of components (i) and (ii) is less than or equal to 100% by weight.

[0098] Preferably, the pellets are (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) containing up to 10% by weight of additional components different from components (i) and (ii), the sum of components (i), (ii) and (iii) being up to 100% by weight.

[0099] Preferably, the pellets are (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 0 to 10% by weight of an additional component different from components (i) and (ii) The total of components (i), (ii) and (iii) is 100% by weight.

[0100] Preferred are pellets having a rod shape with a circular diameter of between 2 mm and 4 mm.

[0101] Pellets having a length 1 to 3 times the diameter of the circle are preferred.

[0102] A further embodiment of the present invention is a method of making a stabilized polymer comprising the steps of: (AP) introducing the pellets into a polymer to obtain a pellet-polymer mixture; (BP) subjecting the pellet-polymer mixture to a temperature in the range of 120-340° C. under mechanical agitation to obtain a stabilized polymer Including, the polymer is a polyolefin, a polystyrene, or a mixture thereof; The pellets comprise: (i) 87-97% by weight of a polymeric stabilizer, which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); and (ii) 3 to 13 weight percent of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. Wt% is based on the weight of the pellet; This is the method.

[0103] The weight percentages of components (i) and (ii) in the pellets are based on the weight of the pellets. Thus, the weight percentages of all components contained in the pellets, including components (i) and (ii), add up to 100% by weight in total. In other words, the sum of all components is 100% by weight. The sum of components (i) and (ii) is less than or equal to 100% by weight.

[0104] Preferably, in the method for producing a stabilized polymer, the pellets are (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 10% by weight or less of an additional component different from components (i) and (ii). wherein the sum of components (i), (ii) and (iii) is not more than 100% by weight.

[0105] Preferably, in the method for producing a stabilized polymer, the pellets are (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa; and (iii) 0 to 10% by weight of an additional component different from components (i) and (ii) The total of components (i), (ii) and (iii) is 100% by weight.

[0106] In step (AP), the size of the pellets is preferably of an appropriate size, since if the pellets are too large, it will be more difficult to introduce, mix (blend) and disperse them in the polymer.

[0107] In step (BP), the pellet components are homogeneously dispersed and / or dissolved in the polymer to be stabilized under mechanical stirring. This is aided by heat exposure of the pellet-polymer mixture, which leads on the one hand to a decrease in the viscosity of the polymer and on the other hand to the melting of the pellet components when the respective melting ranges of the components are reached. Preferably, the temperature in step (BP) is in the range of 135°C to 330°C, very preferably 150°C to 310°C, in particular 180°C to 300°C, very particularly 190°C to 290°C, in particular 200°C to 280°C, very particularly 210°C to 260°C.

[0108] Polyolefins are, for example: 1. Homopolymers of mono- and diolefins, such as polypropylene, polyisobutylene, poly-but-1-ene, poly-4-methylpent-1-ene, polyvinylcyclohexane, polyisoprene or polybutadiene, as well as polymers of cycloolefins, such as polymers of cyclopentene or norbornene, polyethylene, such as high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or mixtures thereof, such as mixtures of polypropylene and polyisobutylene, mixtures of polypropylene and polyethylene (e.g. PP / HDPE, PP / LDPE) or mixtures of different types of polyethylene (e.g. LDPE / HDPE).

[0109] 2. Copolymers of mono- or diolefins with each other or with other vinyl monomers, such as ethylene / propylene copolymers, propylene / but-1-ene copolymers, propylene / isobutylene copolymers, ethylene / but-1-ene copolymers, ethylene / hexene copolymers, ethylene / methylpentene copolymers, ethylene / heptene copolymers, ethylene / octene copolymers, ethylene / vinylcyclohexane copolymers, ethylene / cycloolefin copolymers, such as ethylene / norbornene, COC, in which 1-olefins are produced in-situ. Ethylene / 1-olefin copolymers; propylene / butadiene copolymers, isobutylene / isoprene copolymers, ethylene / vinylcyclohexene copolymers, ethylene / alkyl acrylate copolymers, ethylene / alkyl methacrylate copolymers, ethylene / vinyl acetate copolymers or ethylene / acrylic acid copolymers and their salts (ionomers), as well as terpolymers of ethylene with propylene and dienes such as hexadiene, dicyclopentadiene or ethylidene-norbornene: and mixtures of such copolymers with each other or with other polyolefins, such as polypropylene / ethylene-propylene copolymers, LDPE / ethylene-vinyl acetate copolymer (EVA) or LDPE / ethylene-acrylic acid copolymer (EAA).

[0110] The monoolefin polyolefins, preferably polyethylene and polypropylene, can be prepared in various ways, especially by the following methods: a) Radical polymerization (usually under high pressure and high temperature) b) Catalytic polymerization using catalysts that contain one or more metals, usually from groups 4, 5, 6 (e.g. chromium) or 7 of the periodic table. These metals usually have one or more ligands, typically oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls and / or aryls, which may be pi- or sigma-coordinated. These metal complexes may be in free form or fixed on a substrate, typically on activated magnesium chloride, titanium(III) chloride, alumina or silicon oxides. These catalysts may be soluble or insoluble in the polymerization medium. The catalysts can be used alone in the polymerization or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metal alkyl oxanes, the metals being elements of groups 1, 2 and / or 3 of the periodic table. The activators may be conveniently modified with further ester, ether, amine or silyl ether groups. These catalyst systems are commonly referred to as Phillips catalysts, Standard Oil Indiana catalysts, Ziegler(-Natta) catalysts, TNZ (DuPont) catalysts, metallocene catalysts or single-site catalysts (SSC).

[0111] Polystyrene is, for example: 1. Homopolymer of styrene.

[0112] 2. Copolymers of styrene with comonomers, such as ethylene, propylene, dienes, nitriles, acids, maleic anhydride, maleimides, vinyl acetate, acrylic acid derivatives and mixtures thereof, such as styrene / butadiene, styrene / acrylonitrile, styrene / ethylene, styrene / alkyl methacrylate, styrene / butadiene / alkyl acrylate, styrene / butadiene / alkyl methacrylate, styrene / maleic anhydride, styrene / acrylonitrile / methyl acrylate, block copolymers of styrene with comonomers, such as styrene / butadiene / styrene, styrene / isoprene / styrene, styrene / ethylene / butylene / styrene or styrene / ethylene / propylene / styrene.

[0113] 3. Graft copolymers of styrene, such as styrene on polybutadiene, styrene on polybutadiene-styrene or polybutadiene-acrylonitrile copolymers, styrene and acrylonitrile on polybutadiene, styrene, acrylonitrile and methyl methacrylate on polybutadiene, styrene and maleic anhydride on polybutadiene, styrene, acrylonitrile and maleimide on polybutadiene, styrene and maleimide on polybutadiene, styrene and alkyl acrylates or methacrylates other than methyl acrylate on polybutadiene, styrene and acrylonitrile on ethylene / propylene / diene terpolymers, styrene and acrylonitrile on polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile on acrylate / butadiene copolymers.

[0114] In the copolymers of polyolefins, at least two different monomers are copolymerized. Polyolefin copolymers having a weight content of polymerized olefin monomers of more than 50% relative to the weight of all polymerized monomers are preferred. In the copolymers of polystyrene, at least two different monomers are copolymerized or one monomer is grafted onto at least one different monomer that is polymerized. Polystyrene copolymers having a weight content of polymerized or grafted styrene of more than 50% relative to the weight of all polymerized or grafted monomers are preferred.

[0115] Preferably the polymer, which is a polyolefin, polystyrene or a mixture thereof, is thermoplastic, i.e. it can be moulded into new shapes at elevated temperatures, for example in the range of 120°C to 340°C, especially 135°C to 330°C.

[0116] Polymers that are polyolefins, polystyrene or mixtures thereof are susceptible to oxidative, thermal or light-induced degradation.

[0117] The amount of pellets added to the polymer, be it polyolefin, polystyrene or a mixture thereof, varies depending on the particular polymer and the desired degree of protection against oxidative, thermal or light-induced degradation. Preferably, the amount of pellets in % by weight is 0.01 to 5% by weight, very preferably 0.02 to 3% by weight, in particular 0.04 to 2% by weight, very particularly 0.05 to 1% by weight, in particular 0.08 to 0.8% by weight, and very particularly 0.1 to 0.4% by weight, based on the weight of the polymer.

[0118] A process for the preparation of a stabilized polymer, in which step (BP) is carried out in an extruder or co-kneader, is preferred.

[0119] In step (AP), the pellets can be added to a polymer that already has a polymer temperature in the range of 120-340° C. For example, the pellets are added to a pre-warmed polymer in an extruder or co-mixer. For example, the pellets are introduced into an already warm, viscous stabilized polymer by a feeder, for example an extruder. Thus, the pellet-polymer mixture immediately has a polymer temperature in the range of 120-340° C. and the pellets start to disintegrate.

[0120] A method for producing a stabilized polymer, wherein the polymer to which the pellets are added in step (AP) has a polymer temperature in the range of 120-340° C. is preferred.

[0121] In step (AP), the pellets can be added to the polymer having a polymer temperature below 40° C. If the polymer is present in the form of pellets, a pellet-polymer mixture is produced comprising pellets of component (a) and polymer pellets of component (b). The polymer pellets have, for example, a cylindrical geometric shape and are obtained, for example, by hot cutting of an extruded warm polymer strand followed by cooling in a water quench. The pellet-polymer mixture obtained in step (AP), in which the polymer is in the form of pellets, can be prepared and stored independently of step (BP) or can be prepared directly before step (BP).

[0122] A process for the preparation of a stabilized polymer, wherein the polymer to which the pellets are added in step (AP) is present in the form of pellets and has a polymer temperature below 40° C. is preferred.

[0123] The definitions and preferences given for the preparation or application of the stabilizing polymer also apply to the further embodiments of the present invention.

[0124] A further embodiment of the present invention is the use of pellets for dust-free handling of the components of the pellets in the manufacture of stabilized polymers, the polymer being a polyolefin, polystyrene or a mixture thereof, the pellets comprising: (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4); and (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion of less than 100 J / g at 101.32 kPa. Wt% is based on the weight of the pellet; The use of pellets.

[0125] The weight percentages of components (i) and (ii) in the pellets are based on the weight of the pellets. Thus, the weight percentages of all components contained in the pellets, including components (i) and (ii), add up to 100% by weight in total. In other words, the sum of all components is 100% by weight. The sum of components (i) and (ii) is less than or equal to 100% by weight.

[0126] Preferably, in the use of the pellets for dust-free handling of the components of the pellets in the manufacture of stabilized polymers, the pellets are (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion at 101.32 kPa of less than 100 J / g; and (iii) 10% by weight or less of an additional component different from components (i) and (ii). wherein the sum of components (i), (ii) and (iii) is not more than 100% by weight.

[0127] Preferably, in the use of the pellets for dust-free handling of the components of the pellets in the manufacture of stabilized polymers, the pellets are (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4); (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion at 101.32 kPa of less than 100 J / g; and (iii) 0 to 10% by weight of an additional component different from components (i) and (ii) The total of components (i), (ii) and (iii) is 100% by weight. EXAMPLES

[0128] The invention is further illustrated without being limited by the following examples, in which percentage values ​​are percentages by weight unless otherwise stated.

[0129] A) Characterization method The average particle size is determined by digital image analysis with a Camsizer P4 from Retsch Technology GmbH unless otherwise stated. The measurement method is dynamic image analysis according to ISO 13322-2.

[0130] The bulk density is determined in accordance with DIN EN ISO 17892-3.

[0131] The Melt Flow Index of polymers is determined according to ISO 1133 using a Goettfert MI-Robo with precisely specified parameters.

[0132] Differential scanning calorimetry (DSC) is performed according to EN ISO 11357-3 at atmospheric pressure. The heating cycle is: (a) 10 °C / min and 30 mL / min N 2 (b) from 0°C to 200°C at 10°C / min and 30mL / min N 2(c) from 200°C to 0°C at 10°C / min and 30mL / min N 2 from 0° C. to 200° C. The melting range, melting peak temperature and melting enthalpy are determined for the heating cycle (c).

[0133] High temperature gel permeation chromatography (HT-GPC) is measured according to ISO 16014-4. The instrument used is an Agilent PL-GPC220 equipped with an RI detector. As a precolumn, one Agilent PFgel Olexis Guard 50x7.5mm column (part number PL1110-1400) is used. As columns, three Agilent PLgel Olexis 13μm 300x7.5mm columns (part number PL1110-6400) are used. The column temperature is 150°C. The calibration standards are Agilent polystyrene and High EasiVial GPC / SEC calibration standards (part number PL2010-0201 and part number PL2010-0202). Trichlorobenzene is used as the eluent with a flow rate of 1mL / min, a sample concentration of 3mg / mL, and an injection volume of 200μL. The determined number average molecular weight Mn and the determined weight average molecular weight Mw are used to calculate the polydispersity index (PD) as the ratio of Mw to Mn.

[0134] The sieve analysis is carried out by digital image analysis with a Camsizer P4 from Retsch Technology GmbH. The measurement method is dynamic image analysis according to ISO 13322-2) with the D10, D50 and D90 values.

[0135] The Norner abrasion test is a mechanical treatment of the dosage form being tested using a vibrating sieve shaker and glass beads. An initial sieve analysis is performed for 1 minute, after which a further sieve is performed using glass beads on the sieve deck to mechanically impact the material and measure the change in sieve fraction after 5, 10 and 20 minutes. The sieves selected are 200 μm, 500 μm, 1 mm, 1.6 mm, 2.5 mm and 4 mm in descending order. The glass beads used (Sigmund Lindner GmbH, Type P) are soda-lime glass beads with a fine matte surface, 16 mm ± 0.02 mm, weighing 5.36 g / bead.

[0136] The test procedure is as follows: 1. Place 50 g of sample in a sieve shaker without glass beads and sieve for 1 minute at an amplitude of 1 mm. Measure the mass on each sieve tray and sieve pan.

[0137] 2. Add 8 glass beads onto the 500 μm sieve, 9 glass beads onto the 1.0 mm sieve, 10 glass beads onto the 1.6 mm sieve, and 11 glass beads onto the 2.5 mm sieve. Continue sieving for 5 minutes, after which weigh on each sieve tray and sieve pan.

[0138] 3. Continue sieving for an additional 5 minutes and repeat the weighing procedure.

[0139] 4. Continue sieving for an additional 10 minutes and repeat the weighing procedure.

[0140] A Retsch Sieve Shaker AS200 manufactured by Retsch GmbH is used as the sieve shaker.

[0141] Total fines is the sum of all material recovered from the lower plate and the 200 μm mesh sieve. Thus, the fraction of the sample (<500 μm) that is generated under the abrasion pressure and falls through the 500 μm mesh sieve is considered to be fines. The particle size fraction (wt%) of <500 μm after 20 minutes is the key result (Norner value) to determine the abrasion and impact resistance of the dosage form tested. The results can range from 0% for "very stable" to 100% for "very unstable".

[0142] The average weight of the pellets is determined by taking a specific number of pellets (approximately 45 pellets), weighing the specific number of pellets to determine a total weight, and dividing the total weight by the specific number of pellets.

[0143] The average length of the pellets is assumed to be 0.95g / cm 3 The pellet diameter is calculated by multiplying the pellet diameter by the area of ​​a circle having a diameter of 3 mm.

[0144] B) Starting materials SM-PS-1: Irgafos 168 Irgafos 168 (TM, available from BASF SE, melting range 180-183°C) is the compound shown below as tris(2,4-di-tert-butylphenyl) phosphite (CAS No. 31570-04-4). [ka] in powder form, i.e. in the form of a loose bulk material having a bulk density of 467 g / L and an average particle size of 400 μm.

[0145] SM-PA-1:Licocene PP 1302 Licocene PP 1302 (trademark, available from Clariant, commercial technical form: granules) is a propylene-ethylene copolymer wax (CAS number 9010-79-1) synthesized from propylene and ethylene using metallocene catalysts. The branches of the long polymer chains are divided into short chains (-CH 3) Some physicochemical properties were measured and are shown in Table B-1. The technical data sheet lists a density of 0.87 g / cm3 at 23 °C according to ISO 1183. 3 The technical data sheet states that the dropping point according to ASTM D3954 is 87-93 °C. The technical data sheet states that the viscosity at 170 °C according to DIN 53019 is 150-250 mPas. The sieve analysis of the material in the technical form of granules was measured and is shown in table B-2. A bulk density of 338 g / L is measured. The material in the technical form of granules is used for compaction.

[0146] SM-PA-2: Petrolite EP-700 Petrolite EP-700 (trademark, available from Baker Hughes) is a propylene-ethylene copolymer wax (CAS number 9010-79-1). Controlled branching of the long polymer chains results in the formation of short chains (-CH) from propylene. 3 ). Some physicochemical properties were measured and are shown in Table B-1. The technical data sheet states that the drop melting point according to ASTM D-127 is 96°C. The technical data sheet states that the viscosity at 99°C is 12 pcs (120 mPas). Petrolite EP-700 is ground in a Pallmann disc mill PF300. The sieve analysis of the resulting grind was measured and is shown in Table B-2. The bulk density of the grind is measured to be 473 g / L. The grind is used for compaction.

[0147] SM-PA-3: Luwax AL-3 Luwax AL-3 (trademark, commercially available as a powder from BASF) is a polyethylene wax (CAS number 9002-88-4) synthesized by high pressure polymerization. The long polymer chain branches are long chain (-[CH 2 -CH 2 -] nSome physicochemical properties were measured and are shown in Table B-1. The technical data sheet includes a density of 0.91-0.925 g / cm3 at 23°C according to DIN 53479 and ASTM D-792. 3 The technical data sheet states that the dropping point (Ubbelohde) is 101-112°C according to DIN 51801 and ASTM D-3954. The technical data sheet states that the melting point (DSC) is 102-108°C according to DIN 51007 and ASTM D-3418. The technical data sheet states that the melt viscosity at 120°C is 135-240mm according to DIN 51562 and ASTM D-2162. 2 / s. The sieve analysis of the material in technical form powder was determined and is given in Table B-2. A bulk density of 495 g / L is determined. The material in technical form is used for compaction.

[0148] SM-PA-4: Dow PG 7008 Dow PG 7008 (trademark, available from Dow Chemicals) is a low density polyethylene (CAS number 9002-88-4). Several physicochemical properties were measured and are shown in Table B-1. The technical data sheet lists a density of 0.918 g / cm at 23°C according to ASTM D-792. 3 The technical data sheet states that the melting temperature (DSC) is 106°C. The technical data sheet states that the Vicat softening temperature according to ISO 306 / A is 89.0°C. The technical data sheet states that the melt index according to ISO 1133 is 7.7 g / 10 min (190°C / 2.16 kg). Dow PG 7008 is ground in a Pallmann disc mill PF300. The sieve analysis of the resulting grind is determined and is shown in Table B-2. The bulk density of the grind is determined to be 285 g / L. The grind is used for compaction.

[0149] SM-PA-5: Borflow HL 708 FB Borflow HL 708 FB (trademark, available from Borealis) is a polypropylene (CAS number 9003-07-0). Some physicochemical properties were measured and are shown in Table B-1. The technical data sheet states that the melting temperature (DSC) is 158°C. The technical data sheet states that the melt index according to ISO 1133 is 800 g / 10 min (130°C / 2.16 kg). Borflow HL 708 FB is ground in a Pallmann disc mill PF300. The sieve analysis of the resulting grind is measured and is shown in Table B-2. The bulk density of the grind is measured to be 365 g / L. The grind is used for compaction.

[0150] [Table 1]

[0151] [Table 2]

[0152] C) Preparation of the Compression Mixture A compression mixture consisting of polymeric stabilizers and processing aids is prepared by blending the starting materials shown in Table C-1 in a 100-L MTI blender for 5 minutes at room temperature.

[0153] [Table 3]

[0154] D) Flakes by roll compression In the case of Example D-1-1, the starting material SM-PS-1 (100%) is compacted and agglomerated through a roll compaction process to obtain comparative flakes (flake agent). The powdered SM-PS-1 in the hopper is forced through a feed screw into the compaction zone. The compaction zone is formed by the gap remaining between two rolls with slightly scratched surfaces rotating towards each other. The rolls are cooled with cold water and the temperature is maintained around room temperature. A suitable laboratory roll compactor is, for example, the model WP 50N / 75 (roll diameter: 150 mm, roll length: 75 mm, maximum pressing capacity: 12.8 t, maximum linear pressure: 1.71 t / cm) from Alexanderwerk GmbH, Germany. The compressed starting material, which passes through the compression zone and becomes a plate, is granulated by a sieve granulator equipped with a 1.6 mm sieve (e.g., model GLA-ORV-0215 ​​from Frewitt Ltd, Switzerland is suitable) to produce free-flowing flakes (= flakes D-1-1). Norner abrasion tests are carried out on the flakes D-1-1, the results of which are shown in Table E-1.

[0155] E) Pellets compressed using a ring die pelletizer A ring die pelletizer, namely the Muench Pelletizer RMP 250, is used for the compression test of the materials listed in Table E-1. The Muench ring die pelletizer is shown, for example, in FIG. 18 on p. 898 of the paper "Produktgestaltung ueber mechanisches Agglomerieren von Pulvern" W. Raehse, Chemie Ingeneur Technik, 2015, 87, No. 7, 881 - 902. The Muench Pelletizer RMP 250 comprises a rotatable ring die equipped with nozzles, for example 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 the width is about 4 cm. Rows with two or three nozzles fit this width. The nozzles extend at an angle of 60° to the inside of the ring die. In this specification, the nozzle diameter is defined as the minimum diameter of the cylindrical channel of the nozzle, and the press length is defined as the distance where the minimum diameter fits. The cylindrical channel of the nozzle may be expanded subsequently to the press length, but the expanded part of the cylindrical channel does not contribute to the increase of friction by the material being compressed. Here, the nozzle channel is not expanded. The specifically applied nozzle diameter and press length are shown in Table E-1. The material for compression is fed at room temperature by gravitational measurement into the pellet press section, which comprises a nozzle die and two rollers, by a volumetric single screw feeder arranged on the pellet press section of the ring die pelletizer. The rollers are 96 mm in diameter and 30 mm wide, respectively, and have a corrugated surface. In the pellet press section, the two rollers push the material into the nozzle of the rotating ring die. There, the material is compressed and heated by shear forces to a temperature at which the processing aids start to soften. In the sintering process, the compressed material is granulated into cylindrical pellets. To start the process, the ring die rotation is set to a peripheral speed of about 4 m / s at the inner surface of the ring die, i.e. at a distance of 12.5 cm from the axis of rotation of the ring die. The material for compression is fed to the press section as a powder. An initial start-up phase of about 15 minutes is required until the process is running steadily.Initially, the powder of the material to be pressed flows through the nozzle, which changes to the formation of strands by a part of the material to be pressed, and the ring die, rollers and nozzle reach a stable temperature. If the temperature is too high for the material to be pressed, it may result in the formation of a paste-like mass, which prevents further feeding of the material to be pressed. At the outlet of the nozzle, two knives, the distance of which is adjustable to the ring die, cut / break the strands into pellets with a length of about 1-3 times the pellet diameter, i.e. about 3 mm-9 mm. Ideally, the variation in length is minimal, but some variation due to cutting / breaking cannot be avoided. Table E-1 indicates whether pellets are obtained and therefore also whether strands are formed. When the process is running stably, the temperature of the material leaving the nozzle of the die is measured by an IR temperature sensor by measuring the emitted IR radiation in a non-contact manner and is shown in Table E-1 as the surface temperature of the strand. Statistically, the IR radiation emitted from the outer surface of the ring is also included. However, when the process is running stably, the ring die heats up to about the surface temperature of the strand. The ring die itself is not heated (except for example E-1-4) or cooled, but is heated due to friction of the material to be compressed. The pellets obtained are sieved through a 1.6 mm sieve (a vibrating laboratory sieve with a diameter of 200 mm) to separate the fines from the pellets obtained. The amount of fines removed by sieving is shown in Table E-1 based on the total amount of material to be compressed. The removed fines can be directly reused as material to be compressed. The pellets were cooled to room temperature. If pellets were obtained, a Norner abrasion test of the pellets after sieving was performed, the results of which are shown in Table E-1. Further properties of the pellets obtained are shown in Table E-2. Photographs of the pellets obtained in examples E-1-1 to E-1-8 are shown in Figures 1 to 8.

[0156] [Table 4]

[0157] From the results in Table E-1: - Example D-1-1 shows that SM-PS-1 (Irgafos 168) can be cold pressed into flakes, but the flakes have poor Norner abrasion test results. - Example E-1-4 shows that special pre-heating is required to pelletize SM-PS-1 (Irgafos 168) without processing aids in a ring die pelletizer. It can be concluded that the melting point of SM-PS-1 itself is too high and therefore a processing aid is required as a binder to enable stable pellet formation. - Example E-1-2 vs. Example E-1-3 shows that longer die length results in higher friction and higher process temperatures, but this does not improve Norner wear test results. - Example E-1-3 vs. Example E-1-4 shows that SM-PA-1 (Licocene 1302) results in pellets with significantly better Norner abrasion test results than without the processing aid. - Example E-1-2 vs. Example E-1-5 shows that SM-PA-1 (Licocene 1302) results in pellets with significantly better Norner abrasion test results than SM-PA-2 (Petrolite EP-700), even though both processing aids are propylene-ethylene copolymer waxes. - Examples E-1-5 and E-1-8 show that the amount of fines generated in the process itself and removed by a 1.6 mm sieve is not a reliable indicator of a useful Norner abrasion test result.

[0158] [Table 5]

[0159] From the results in Table E-2: - Example E-1-4 shows that SM-PS-1, which does not contain processing aids, only results in pellets with low average weight. - Example E-1-7 shows that a high average weight is not a reliable indicator of a beneficial Norner Abrasion test result. - The resulting pellets look fairly similar in the photograph, except for the pellet obtained in Example E-1-4, and are therefore not a reliable indicator of useful Norner abrasion test results. Some embodiments are given below. Item 1 1. A method for producing pellets in a pelletizer having a roller and a die with a nozzle, the method comprising: (A) pressing the compression mixture with a roller through a nozzle to obtain a strand; and (B) Breaking the strands to obtain pellets Including, The compression mixture is (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4), and (ii) 3 to 13 weight percent of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. Including, Weight percent is based on the weight of the compression mix. method. Section 2 Item 3. The method according to item 1, wherein the enthalpy of fusion is determined by differential scanning calorimetry in accordance with EN ISO 11357-3. Section 3 Item 3. The method according to item 1 or 2, wherein the processing aid has a weight average molecular weight of more than 10,000 Da and less than 40,000 Da. Section 4 The method according to any one of items 1 to 3, wherein the processing aid has a melting peak temperature of more than 50 ° C. and less than 85 ° C. Section 5 5. The method according to item 4, wherein the melting peak temperature is determined by differential scanning calorimetry in accordance with EN ISO 11357-3. Section 6 6. The method according to any one of items 1 to 5, wherein the processing aid is a waxy propylene-ethylene copolymer. Section 7 The compression mixture is (i) 89 to 96% by weight of a polymer stabilizer; (ii) 4 to 11% by weight of processing aids The method according to any one of items 1 to 6, comprising: Section 8 Item 8. The method according to any one of items 1 to 7, wherein the strand has a surface temperature of more than 50°C and less than 110°C. Section 9 The method is (Pre-A) feeding the compression blend into a pelletizer, the compression mixture being in powder form; The method according to any one of items 1 to 8, wherein step (Pre-A) is carried out before step (A). Section 10 Item 10. The method according to any one of items 1 to 9, wherein the pelletizer is a ring die type pelletizer, the die having a geometric shape of a ring with an inner side and an outer side, and the nozzle corresponds to a passage from the inner side to the outer side, or the pelletizer is a flat die type pelletizer, the die having a geometric shape of a flat plate with an upper side and a lower side, and the nozzle corresponds to a passage from the upper side to the lower side. Section 11 Item 11. The method according to item 10, wherein in a ring die type pellet machine, the ring rotates and the rollers are fixed on a rotating shaft, and in a flat die type pellet machine, the die is fixed and the rollers are rotated on a rotating shaft. Section 12 Item 12. The method according to any one of items 1 to 11, wherein the nozzle has a nozzle diameter and a press length, and the ratio of the press length to the nozzle diameter is 2 to 8. Section 13 Item 13. The method according to any one of items 1 to 12, wherein the roller surface is wavy. Section 14 Item 14. The method according to any one of items 1 to 13, wherein the pelletizing machine is a ring die type pelletizing machine. Section 15 Item 15. The method according to any one of items 1 to 14, wherein the pelletizer comprises two or more rollers and the die comprises two or more nozzles. Item 16 A pellet, (i) 87 to 97% by weight of a polymer stabilizer which is tris(2,4-ditert-butylphenyl) phosphite (CAS number 31570-04-4), and (ii) 3 to 13 weight percent of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. Including, Weight percent is based on the weight of the pellet. pellet. Item 17 Item 17. The pellet according to item 16, having a round bar shape and a circular diameter of the round bar between 2 mm and 4 mm. Section 18 Item 18. The pellet according to item 17, having a length 1 to 3 times the diameter of the circle. Section 19 Item 16. Use of pellets as defined in any one of items 16 to 18 for dust-free handling of the components of the pellets in the production of stabilized polymers, wherein the polymer is a polyolefin, a polystyrene or a mixture thereof. Section 20 1. A method for making a stabilized polymer, comprising: (AP) A step of introducing the pellets defined in any one of paragraphs 16 to 18 into a polymer to obtain a pellet-polymer mixture; (BP) subjecting the pellet-polymer mixture to a temperature in the range of 120-340° C. under mechanical agitation to obtain a stabilized polymer Including, The polymer is a polyolefin, a polystyrene, or a mixture thereof; method. Section 21 A compression mixture comprising: (i) 87-97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4); and (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion of less than 100 J / g at 101.32 kPa. Including, Weight percent is based on the weight of the compression mix. Compression mixture.

Claims

1. 1. A method for producing pellets in a pelletizer having a roller and a die with a nozzle, the method comprising: (A) pressing the compression mixture with a roller through a nozzle to obtain a strand; and (B) Step of cutting the strand to obtain pellets Including, The compression mixture is (i) 87 to 97% by weight of a polymeric stabilizer which is tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4), and (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. Including, Weight percent is based on the weight of the compression mix. method.

2. 2. The method of claim 1, wherein the enthalpy of fusion is determined by differential scanning calorimetry in accordance with EN ISO 11357-3.

3. 3. The method according to claim 1 or 2, wherein the processing aid has a weight average molecular weight of more than 10,000 Da and less than 40,000 Da.

4. The method according to any one of claims 1 to 3, wherein the processing aid has a peak melting temperature of more than 50°C and less than 85°C.

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

6. The method of any one of claims 1 to 5, wherein the processing aid is a waxy propylene-ethylene copolymer.

7. The compression mixture is (i) 89 to 96% by weight of a polymeric stabilizer; (ii) 4 to 11% by weight of processing aids The method according to any one of claims 1 to 6, comprising:

8. 8. The method according to any one of claims 1 to 7, wherein the strands have a surface temperature of more than 50°C and less than 110°C.

9. The method is (Pre-A) feeding the compression blend into a pelletizer, the compression mixture being in powder form; The method according to any one of claims 1 to 8, wherein step (Pre-A) is carried out before step (A).

10. 10. The method according to any one of claims 1 to 9, wherein the pelletizer is a ring die pelletizer, the die having a ring geometry with an inner side and an outer side, and the nozzle corresponds to a passage from the inner side to the outer side, or the pelletizer is a flat die pelletizer, the die having a flat plate geometry with an upper side and a lower side, and the nozzle corresponds to a passage from the upper side to the lower side.

11. 11. The method according to claim 10, wherein in a ring die pelletizer, the ring rotates and the rollers are provided with a fixed shaft, and in a flat die pelletizer, the die is fixed and the rollers are provided with a rotating shaft.

12. 12. The method of any one of claims 1 to 11, wherein the nozzle has a nozzle diameter and a press length, the ratio of the press length to the nozzle diameter being between 2 and 8.

13. The method according to any one of claims 1 to 12, wherein the roller surface is corrugated.

14. The method according to any one of claims 1 to 13, wherein the pelletizer is a ring die pelletizer.

15. The method according to any one of the preceding claims, wherein the pelletizer comprises two or more rollers and the die comprises two or more nozzles.

16. A pellet, (i) 87 to 97% by weight of a polymeric stabilizer which is tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4), and (ii) 3 to 13 wt. % of a processing aid that is a propylene-ethylene copolymer and has a fusion enthalpy of less than 100 J / g at 101.32 kPa. Including, Weight percent is based on the weight of the pellet. pellet.

17. 17. The pellet according to claim 16, having a rod shape, the diameter of the circle of the rod being between 2 mm and 4 mm.

18. 18. The pellet of claim 17, having a length between 1 and 3 times the diameter of the circle.

19. Use of pellets as defined in any one of claims 16 to 18 for dust-free handling of the components of the pellets in the manufacture of stabilized polymers, wherein the polymer is a polyolefin, a polystyrene or a mixture thereof.

20. 1. A method for making a stabilized polymer, comprising: (AP) introducing pellets as defined in any one of claims 16 to 18 into a polymer to obtain a pellet-polymer mixture; (BP) subjecting the pellet-polymer mixture to a temperature in the range of 120-340° C. under mechanical agitation to obtain a stabilized polymer. Including, The polymer is a polyolefin, a polystyrene, or a mixture thereof; method.

21. A compression mixture comprising: (i) 87 to 97% by weight of a polymeric stabilizer having a powder physical form, the polymeric stabilizer being tris(2,4-ditert-butylphenyl)phosphite (CAS number 31570-04-4); and (ii) 3 to 13 weight percent of a processing aid having a powder physical form, the processing aid being a propylene-ethylene copolymer and having an enthalpy of fusion of less than 100 J / g at 101.32 kPa. Including, Weight percent is based on the weight of the compression mix. Compression mixture.

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