Method for producing pellets in a pelletizer, pellets and use thereof

Abstract

The present invention relates to a method for manufacturing pellets in a pelletizer, the method comprising the steps of: (a) pressing a compacted mixture by a roller through a nozzle to obtain a strand, and (b) crushing the strand to obtain a pellet, wherein the compacted mixture comprises (i) 87-97 weight % of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No.31570-04-4), and (ii) 3-13 weight % of a processing aid, which is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa. The pellets can be used to manufacture dust-free processing of the polymer stabilizer in a stabilized polymer. In addition, a method for stabilizing a polymer is disclosed, the polymer being a polyolefin, polystyrene, or a mixture thereof, comprising adding the pellets to the polymer.

Description

[0001] The present invention relates to a method for producing pellets, comprising pressing a compaction mixture comprising a polymer stabilizer (which is tris(2,4-di-tert-butylphenyl) phosphite) and a processing aid through the nozzle of a pellet mill to obtain strands, and comminuting the strands to obtain pellets. Another embodiment is a pellet comprising a polymer stabilizer and a processing aid. Another embodiment is the use of the pellets in the dust-free processing of components thereof in the manufacture of stabilized polymers. Another embodiment is a method for producing stabilized polymers, comprising incorporating the pellets into a polymer (which is a polyolefin, polystyrene, or a mixture thereof) to obtain the stabilized polymer. Another embodiment is a compaction mixture.

[0002] Organic polymers used as structural materials to construct or form part of articles are susceptible to degradation by oxidation, heat, or light. Short-term degradation occurs when the polymer is processed, for example, when the polymer obtained from the polymer synthesis is mechanically converted into the desired final article or intermediate article. Intermediate articles are often the product of a process used to incorporate specific desired additives into the polymer obtained from the polymer synthesis. Short-term degradation is usually characterized by relatively short exposure to relatively high process temperatures (e.g., above 80° C. to 330° C.), which in many cases occurs in combination with mechanical stress.

[0003] The incorporation of polymer stabilizers into organic polymers for stabilization against degradation by oxidation, heat, or light has long been known. Polymer stabilizers are typically incorporated into thermoplastic polymers during processing, where the heated polymer has a reduced viscosity or is near-liquid, thus facilitating uniform distribution of the polymer stabilizer throughout the polymer. Polymer stabilizers are typically solid at room temperature and obtained as powders during their synthesis. Practical problems arise when incorporating polymer stabilizers in powder form. Handling powders often generates dust. Dust is a critical issue from the perspectives of occupational health for workers in manufacturing plants, plant safety (e.g., dust explosions), and plant cleanliness (e.g., powder contamination of plant equipment). Furthermore, powder incorporation into polymers is typically not performed in batches. Instead, continuous addition of powder to a polymer, typically in amounts less than 0.5% by weight of the polymer, is prone to fluctuations in the actual amount incorporated at a given moment. Consequently, large total amounts of polymer contain statistically identical amounts of polymer stabilizer, but this is not necessarily true for individual units outside the total amount of polymer.

[0004] Several methods are known for providing suitable dust-free formulations of polymer stabilizers. One direction is to provide suitable dust-free formulations without adding other ingredients, i.e., not needing ingredients as polymer stabilizers. For example, the polymer stabilizer in powder form is aggregated via roller compaction to obtain a thin sheet. Another method is to form a tablet from the polymer stabilizer in powder form by melting the polymer stabilizer and solidifying a single drop of the melt on a cooling surface. Another method is to heat and knead the polymer stabilizer mentioned at a temperature higher than the softening point of the polymer stabilizer in an extruder, extrude the heated mass (mass) through a die to form a warm strand and cut the warm strand into pellets, and form pellets from the polymer stabilizer in powder form. Another direction is to provide suitable dust-free formulations by adding other ingredients (i.e., not needing ingredients as polymer stabilizers). Other ingredients (sometimes referred to as compacting aids, adhesives, or processing aids) are typically used as a hot melt adhesive of polymer stabilizer powder or its particles when the other ingredients of the polymer are also masterbatch polymers or carrier polymers. Whether the polymer stabilizer itself melts depends, at least in part, on the applied temperature and the chemical properties of the other ingredients associated with the polymer stabilizer, in particular whether there is any miscibility. The addition of other ingredients to a polymer stabilizer dosage form has advantages. In particular, a polymer stabilizer dosage form can be initially rendered dust-free simply by sieving or screening the dust at the end of its manufacture. However, the abrasion resistance of the initially dust-free dosage form is a characteristic that is relevant with regard to the transportation of the dosage form and the associated dust formation.

[0005] Tris(2,4-di-tert-butylphenyl) phosphite (CAS No. 31570-04-4) is a polymer stabilizer used as a short-term processing stabilizer. It has a melting range of 180-183° C. and is contained, for example, in Irgafos 168 (TM, commercially available from BASF SE).

[0006] JP H06-254845 relates to a stabilizer having anti-pulverization properties and dispersibility obtained by a method in which, after a heat stabilizer powder and a powder of an organic compounding agent having a lower melting point or softening point than the heat stabilizer are mixed at a prescribed ratio, the mixture is fed into a ring grid plate and extruded from the grid plate into a granular shape by means of a rotating roller.

[0007] US Pat. No. 5,846,656 relates to a stabilization system for stabilizing polymeric materials against ultraviolet light and thermooxidative degradation, wherein the stabilization system is 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 the stabilizer from melting. The stabilizer compound comprises from 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 agent that prevents melting may be a compound derived from a fatty acid or a fatty alcohol, or a fatty acid or a fatty alcohol, or a combination of fatty acids or fatty alcohols, comprising from 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 50-100°C, preferably from 50 to about 80°C. Alternatively, the agent that prevents melting may be a lubricant having a small particle size, comprising from about 2 to 50% by weight of the homogeneous mixture.

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

[0009] WO 2008-033410 relates to high-concentration pelletized additive concentrates or polymer stabilizers or blends and formulations thereof that can be used in various polymerization processes to enhance stability. The pelletized additive concentrates contain at least 10% by weight of a carrier polymer and are obtained in the examples by heating the additive mixture along with the carrier polymer in an extruder at a temperature above the carrier polymer's melting temperature but below the melting temperature of the primary additives, and then cutting the warm strands into pellets. Example 4 produces pellets having a tris(2,4-di-tert-butylphenyl) phosphite content of 48% by weight, a total polymer stabilizer content of 70% by weight, and a polyethylene content of 30% by weight as the carrier polymer.

[0010] There is still a demand for other solid dosage forms of polymer stabilizers (which are tris(2,4-di-tert-butylphenyl) phosphite) that are initially in powder form as starting materials. In the first aspect, the manufacture of dosage units or dosage units should ideally occur without warming the polymer stabilizer or at least minimizing it. First, this saves process energy, which is necessary to warm the polymer stabilizer by direct heating or by indirect heating (i.e., converting mechanical stress into thermal energy), which causes the temperature of the processed polymer stabilizer to increase significantly. Second, this also avoids the polymer stabilizer from having to be exposed to increased temperatures. Although unnecessary exposure is generally to be avoided, a single polymer stabilizer may also undergo a phase change, such as when the initial crystalline material is transformed into a viscous state. In addition, the manufacture of the dosage form should occur without producing defective products, i.e., the starting material of the polymer stabilizer used should be processed into a dosage form with a high percentage in a single run. In other words, the amount of rejected products produced should be low, even if the rejected products are in a form that can be directly reused as starting materials. The example of removing defective products is to sieve the desired dosage form to obtain the initial dust-free dosage form. In the second aspect, the dosage form of the polymer stabilizer should remain stable during storage and transportation after its manufacture. In particular, the initial dust-free dosage form can be produced again by wearing the dosage form unit relative to each other when exposed to vibration, such as during filling into the bag, when conveying the filled bag, or when the feeding operation of the dosage form unit for incorporating into the polymer to be stabilized. Therefore, a certain degree of abrasion resistance of the dosage form is desirable. In the third aspect, the dosage form unit should ideally be less diverse in its shape and weight, because this allows for more accurate feeding of the dosage form unit when being incorporated into the polymer to be stabilized. The result of more accurate feeding is that, especially when continuously adding the polymer to be stabilized, the concentration of the polymer stabilizer fluctuates less in the stabilized polymer. In other words, the local concentration of the polymer stabilizer in a certain part of the stabilized polymer shows less deviation from the average concentration of the polymer stabilizer in the entire stabilized polymer. If the feeding of the dosage form unit occurs at a certain stage when it is incorporated into the polymer to be stabilized, wherein the polymer itself is still present as a solid unit (e.g., pellets), it is advantageous that the dosage form unit is relatively similar to the solid unit of the polymer in terms of shape and weight. This is not conducive to the separation of the mixture of the dosage form unit and the solid unit of the polymer to be stabilized, but rather transported as a mixture. An example of transport is that the mixture of the polymer to be stabilized and the polymer stabilizer is pneumatically transported from a storage facility to an apparatus for incorporating the polymer, such as an extruder. In a fourth aspect, the dosage form of the polymer stabilizer should contain a low content of auxiliary ingredients. The auxiliary ingredients may only exist during the manufacture of the dosage form, such as by adding a solvent, and thereafter removed. The auxiliary ingredients may exist permanently, i.e., the composition of the dosage form contains the auxiliary ingredients to be incorporated into the polymer to be stabilized. In a fifth aspect, the individual polymer stabilizer molecules contribute to the stabilization of the polymer in an ideal uniform distribution throughout the polymer to be stabilized.Alternatively, if the polymer stabilizer is insoluble as an individual molecule in the polymer to be stabilized, aggregates of individual molecules of the insoluble polymer stabilizer, or even larger particles derived from aggregates of individual polymer stabilizer molecules, are uniformly distributed in the polymer to be stabilized. The potential impact of the dosage form on the distribution of the polymer stabilizer is evident by considering that initially all polymer stabilizer molecules are concentrated in the dosage form, but thereafter all polymer stabilizer molecules are ideally uniformly distributed in the polymer to be stabilized. A nonuniform distribution of the polymer stabilizer in the polymer to be stabilized can also be seen as a reduction in stability against degradation of the stabilized polymer compared to a polymer stabilized by a more perfect initial distribution (e.g., when mixing powders of polymer and polymer stabilizer). For example, a nonuniform distribution of the polymer stabilizer in the stabilized polymer can disrupt surface properties when thin polymer films are produced from the stabilized polymer, or can lead to clogging of filters or nozzles when spin-extruding the stabilized polymer. The properties of the polymer to be stabilized and the appropriate polymer stabilizer interact. For example, polyamides melt into a solvent comparable to dimethyl sulfoxide, whereas polyolefins typically melt into only a solvent similar to n-hexane or decalin. Therefore, the possibility of correcting the distribution of the polymer stabilizer in polyolefins is lower than in polyamides during processing of the polymer stabilizer at high temperatures.

[0011] A method for producing pellets in a pelletizer comprising a roller and a die with a nozzle has now been discovered, the method comprising the following steps:

[0012] (A) passing the compacted mixture through a roller and a nozzle to obtain strands, and

[0013] (B) pulverizing the strands to obtain pellets, wherein the compaction mixture comprises

[0014] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0015] (ii) 3-13 wt% of a processing aid which is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0016] And the weight % is based on the weight of the compacted mixture.

[0017] The weight percent of components (i) and (ii) of the compacting mixture is based on the weight of the compacting mixture. Therefore, the weight percent of all components contained in the compacting mixture (including components (i) and (ii)) totals 100 weight percent. In other words, the sum of all components is 100 weight percent. The sum of components (i) and (ii) is less than or equal to 100 weight percent.

[0018] Polymer stabilizers are used to stabilize polymers susceptible to oxidation, heat or light-induced degradation against degradation by oxidation, heat or light. Tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4) is described below.

[0019]

[0020] It is contained, for example, in the commercially available polymer stabilizer Irgafos 168 (TM BASF). It is primarily used as a short-term processing stabilizer. Short-term processing stabilizers are used to combat short-term degradation, which is typically characterized by relatively brief exposure of the polymer to relatively high process temperatures, for example, above 80°C to 330°C, which often occurs in combination with mechanical stress.

[0021] Preferably, the polymer stabilizer is in powder form. The bulk density of the powder is determined according to DIN EN ISO 17892-3. Preferably, the polymer stabilizer is in powder form and has a bulk density, as determined according to DIN EN ISO 17892-3, of greater than 300 g / L and less than 900 g / L, very preferably greater than 350 g / L and less than 600 g / L, in particular greater than 380 g / L and less than 550 g / L, very particularly greater than 400 g / L and less than 500 g / L.

[0022] The processing aid has a melting enthalpy, a melting peak temperature, and a 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 is performed at atmospheric pressure using three consecutive heating cycles, wherein (a) 0°C to 200°C at 10°C / min and 30 mL / min N2, (b) 200°C to 0°C at 10°C / min and 30 mL / min N2, and (c) 0°C to 200°C at 10°C / min and 30 mL / min N2.

[0023] Preferably, the melting enthalpy of the processing aid at 101.32 kPa is higher than 10 J / g and lower than 100 J / g, very preferably higher than 15 J / g and lower than 85 J / g, in particular higher than 17 J / g and lower than 70 J / g, very particularly higher than 18 J / g and lower than 55 J / g, in particular higher than 19 J / g and lower than 40 J / g, very particularly higher than 20 J / g and lower than 30 J / g, most particularly higher than 21 J / g and lower than 25 J / g.

[0024] Preferably, the processing aid has a melting peak temperature of higher than 50°C and lower than 85°C, very preferably higher than 55°C and lower than 83°C, in particular higher than 60°C and lower than 81°C, very particularly higher than 65°C and lower than 80°C, in particular higher than 70°C and lower than 79°C, very particularly higher than 73°C and lower than 78°C, most particularly higher than 75°C and lower than 77°C.

[0025] Preferably, the melting range of the processing aid lies 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.

[0026] A method for producing pellets wherein the processing aid has a melting peak temperature above 50°C and below 85°C is preferred.

[0027] The processing aid for propylene-ethylene copolymers 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, number-average molecular weight, and 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 standard preferably comprises polystyrene.

[0028] Preferably, the weight-average molecular weight of the processing aid for propylene-ethylene copolymers is higher than 10,000 Da (Dalton) and lower than 40,000 Da, very preferably higher than 12,000 Da and lower than 35,000 Da, in particular higher than 14,000 Da and lower than 30,000 Da, very particularly higher than 15,000 Da and lower than 25,000 Da, especially higher than 16,000 Da and lower than 20,000 Da, very particularly higher than 17,000 Da and lower than 18,000 Da.

[0029] Preferably, the number average molecular weight of the processing aid for propylene-ethylene copolymers is higher than 2000 Da and lower than 10000 Da, very preferably higher than 3000 Da and lower than 9000 Da, in particular higher than 4000 Da and lower than 8000 Da, very particularly higher than 5000 Da and lower than 7500 Da, especially higher than 6000 Da and lower than 7000 Da.

[0030] Preferably, the polydispersity index of the processing aid for propylene-ethylene copolymers is higher than 1.3 and lower than 7, very preferably higher than 1.5 and lower than 5, in particular higher than 1.7 and lower than 4, very particularly higher than 1.9 and lower than 3.5, especially higher than 2.1 and lower than 3, very particularly higher than 2.3 and lower than 2.7.

[0031] Preferably, the processing aid for propylene-ethylene copolymers 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, and especially 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.

[0032] Preferably, the polydispersity index as a processing aid for propylene-ethylene copolymers 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, 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, 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 the polydispersity index is greater than 1.9 and less than 3.5 and the weight-average molecular weight is greater than 15,000 Da and less than 25,000 Da, in particular the polydispersity index is greater than 2.1 and less than 3 and the weight-average molecular weight is greater than 16,000 Da and less than 20,000 Da, very particularly the polydispersity index is greater than 2.3 and less than 2.7 and the weight-average molecular weight is greater than 17,000 Da and less than 18,000 Da.

[0033] It will be understood that the polydispersity index is mathematically related to the weight average molecular weight and the number average molecular weight. Therefore, hereinafter, the ranges of polydispersity indices provided are intended to contemplate only those specific polydispersity indices, which can be achieved by selecting an appropriate specific weight average molecular weight from the ranges of weight average molecular weight provided and by selecting an appropriate specific number average molecular weight from the ranges of number average molecular weight provided. Preferably, the polydispersity index of the processing aid for propylene-ethylene copolymers is greater than 1.3 and less than 7, the weight average molecular weight is greater than 10,000 Da (Daltons) and less than 40,000 Da, and the number average molecular weight is greater than 2,000 Da and less than 10,000 Da. Very preferably, the polydispersity index is greater than 1.5 and less than 5, the weight average molecular weight is greater than 12,000 Da and less than 35,000 Da, and the number average molecular weight is greater 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 weight 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 weight 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.

[0034] A method of making pellets is preferred wherein the processing aid has a weight average molecular weight greater than 10,000 Da and less than 40,000 Da.

[0035] 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 of more than 200 g / L and less than 800 g / L, as determined according to DIN EN ISO 17892-3, very preferably more than 250 g / L and less than 600 g / L, in particular more than 280 g / L and less than 400 g / L, very particularly more than 300 g / L and less than 400 g / L.

[0036] Preferably, the processing aid is a propylene-ethylene copolymer which is a wax. Preferably, the processing aid is a propylene-ethylene copolymer wax which is synthesized from propylene and ethylene using a metallocene catalyst. Preferably, the processing aid is a propylene-ethylene copolymer which is a long polymer with short chain (-CH3) branching, very preferably the branches are essentially only short chains, in particular only short chain branching. Preferably, the processing aid is a propylene-ethylene copolymer wax which has a viscosity greater than 0.85 g / cm3 at 23°C according to ISO 1183. 3 And less than 0.90g / cm 3, most preferably 0.87 g / cm 3 The processing aid is preferably a propylene-ethylene copolymer wax having a drop point according to ASTM D 3954 of greater than 80°C and less than 100°C, very preferably greater than 85°C and less than 95°C, in particular within the range of 87°C and 93°C. The processing aid is preferably a propylene-ethylene copolymer wax having a viscosity according to DIN 53019 at 170°C of greater than 50 mPas and less than 750 mPas, very preferably greater than 100 mPas and less than 500 mPas, in particular greater than 120 mPas and less than 350 mPas, in particular within the range of 150 mPas and 250 mPas. The processing aid is preferably a propylene-ethylene copolymer wax, which is Licocene PP 1302.

[0037] Preferred is a method of making pellets wherein the processing aid is a propylene-ethylene copolymer which is a wax.

[0038] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 88-97 wt% of a polymer stabilizer, and (ii) 3-12 wt% of a processing aid.

[0039] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 90-97 wt% of a polymer stabilizer, and (ii) 3-10 wt% of a processing aid.

[0040] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 91 to 97 weight percent of a polymer stabilizer, and (ii) 3 to 9 weight percent of a processing aid.

[0041] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 89-96 wt% of a polymer stabilizer, and (ii) 4-11 wt% of a processing aid.

[0042] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 90-96 wt% of a polymer stabilizer, and (ii) 4-10 wt% of a processing aid.

[0043] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 91 to 96 weight percent of a polymer stabilizer, and (ii) 4 to 9 weight percent of a processing aid.

[0044] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 87-94 wt% of a polymer stabilizer, and (ii) 6-13 wt% of a processing aid.

[0045] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 88-94 wt% of a polymer stabilizer, and (ii) 6-12 wt% of a processing aid.

[0046] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 87-93 wt% of a polymer stabilizer, and (ii) 7-13 wt% of a processing aid.

[0047] Preferred is a method of making pellets wherein the compaction mixture comprises (i) 88-93 wt% of a polymer stabilizer, and (ii) 7-12 wt% of a processing aid.

[0048] In the case where other ingredients other than the polymer and the processing aid are included in the compacted mixture, they are only included in relatively small amounts, i.e., up to 10% by weight (=0-10% by weight). Other ingredients also include mixtures of other ingredients. Therefore, mixtures of other ingredients are only included in relatively small amounts, i.e., up to 10% by weight (=0-10% by weight). Other ingredients are, for example, another polymer stabilizer, another processing aid, or a filler. Another polymer stabilizer is, for example, a phenolic antioxidant, a UV absorber, a hindered amine light stabilizer, a metal deactivator, a phosphite, a phosphonite, a hydroxylamine or an amine N-oxide other than the polymer stabilizer, a sulfur-containing synergist (thiosynergist), an acid scavenger, or a peroxide scavenger. Another processing aid is, for example, oleamide, erucamide, behenamide, or glycerol monostearate. Fillers are, for example, silica, talc, or wollastonite. Preferably, the further component has a light absorption maximum at a wavelength below 380 nm, very preferably below 350 nm, in particular below 300 nm, very particularly below 280 nm, especially below 260 nm, and very particularly no light absorption maximum above 250 nm.

[0049] Preferably, the other ingredients are solid at 23°C and 101.32 kPa. Preferably, the other ingredients are in powder form. The bulk density of the powder is determined according to DIN EN ISO 17892-3. Very preferably, the other ingredients are in powder form and have a bulk density greater than 200 g / L and less than 950 g / L.

[0050] Preferably, the further components are contained in an amount of at most 9 wt.-% (= 0-9 wt.-%), very preferably in an amount of at most 8 wt.-% (= 0-8 wt.-%), in particular in an amount of at most 7 wt.-% (= 0-7 wt.-%), very particularly in an amount of at most 6 wt.-% (= 0-6 wt.-%), in particular in an amount of at most 5 wt.-% (= 0-5 wt.-%), very particularly in an amount of at most 3 wt.-% (= 0-3 wt.-%), most particularly in an amount of at most 1 wt.-% (= 0-1 wt.-%), and very most particularly no further components are contained in the compaction mixture.

[0051] Preferred is a method of producing pellets in a pelletizer comprising a roller and a die having a nozzle, the method comprising the steps of:

[0052] (A) passing the compacted mixture through a roller and a nozzle to obtain strands, and

[0053] (B) crushing the strands to obtain pellets,

[0054] The press-fit mixture comprises

[0055] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0056] (ii) 3-13 wt% of a processing aid which is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0057] (iii) up to 10% by weight of other ingredients, which are different from components (i) and (ii),

[0058] And the sum of components (i), (ii) and (iii) is less than or equal to 100% by weight.

[0059] Preferred is a method of producing pellets in a pelletizer comprising a roller and a die having a nozzle, the method comprising the steps of:

[0060] (A) passing the compacted mixture through a roller and a nozzle to obtain strands, and

[0061] (B) crushing the strands to obtain pellets,

[0062] The compacting mixture consists of the following:

[0063] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0064] (ii) 3-13 wt% of a processing aid which is a propylene-ethylene copolymer and has a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0065] (iii) 0-10% by weight of other ingredients, which are different from components (i) and (ii),

[0066] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0067] A method for producing pellets is preferred wherein the compacting mixture comprises

[0068] (iii) 0-3 wt% of other ingredients.

[0069] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0070] (i) 88-97% by weight of a polymer stabilizer,

[0071] (ii) 3-12 wt% of a processing aid, and

[0072] (iii) 0-9% by weight of other ingredients,

[0073] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0074] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0075] (i) 90-97% by weight of a polymer stabilizer,

[0076] (ii) 3-10 wt% of a processing aid, and

[0077] (iii) 0-7% by weight of other ingredients,

[0078] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0079] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0080] (i) 91-97% by weight of a polymer stabilizer,

[0081] (ii) 3-9 wt% of a processing aid, and

[0082] (iii) 0-6% by weight of other ingredients,

[0083] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0084] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0085] (i) 89-96% by weight of a polymer stabilizer,

[0086] (ii) 4-11 wt% of a processing aid, and

[0087] (iii) 0-7% by weight of other ingredients,

[0088] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0089] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0090] (i) 90-96% by weight of a polymer stabilizer,

[0091] (ii) 4-10 wt% of a processing aid, and

[0092] (iii) 0-6% by weight of other ingredients,

[0093] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0094] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0095] (i) 91-96% by weight of a polymer stabilizer,

[0096] (ii) 4-9 wt% of a processing aid, and

[0097] (iii) 0-5% by weight of other ingredients,

[0098] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0099] A method for producing pellets is preferred wherein the compaction mixture consists of: (i) 87-94% by weight of a polymer stabilizer,

[0100] (ii) 6-13 wt% of processing aids, and

[0101] (iii) 0-7% by weight of other ingredients,

[0102] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0103] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0104] (i) 88-94% by weight of a polymer stabilizer,

[0105] (ii) 6-12 wt% of a processing aid, and

[0106] (iii) 0-6% by weight of other ingredients,

[0107] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0108] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0109] (i) 87-93% by weight of a polymer stabilizer,

[0110] (ii) 7-13 wt% of a processing aid, and

[0111] (iii) 0-6% by weight of other ingredients,

[0112] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0113] Preference is given to a method for producing pellets in which the compaction mixture consists of:

[0114] (i) 88-93% by weight of a polymer stabilizer,

[0115] (ii) 7-12 wt% of a processing aid, and

[0116] (iii) 0-5% by weight of other ingredients,

[0117] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0118] Preferably, the compacted mixture is in solid form at 23 ° C and 101.32 kPa. Very preferably, the compacted mixture is in powder form. Preferably, the compacted mixture in powder form is obtained by physically mixing a polymer stabilizer in powder form with a processing aid in powder form and optionally other ingredients in powder form. Physical mixing does not require the polymer stabilizer or processing aid to be completely melted and does not require the polymer stabilizer or processing stabilizer to be dissolved in a solvent and then evaporating part or all of the solvent. The solid particles of the powder of components (i), (ii) and optionally (iii) are evenly distributed in the compacted mixture. Physical mixing can be carried out in batches or continuously.

[0119] The compaction mixture is the feed material in the pelletizing process using a pelletizer. The compaction mixture is typically fed continuously by gravity into a section of the pelletizer comprising a die with a nozzle and rollers. If the temperature of the compaction mixture is too high when it is fed into the section of the pelletizer comprising the die with a nozzle and rollers, a pasty mass forms in the roller area, which can lead to failure of the production process. The temperature of the compaction mixture during feeding is preferably below 40°C, and most preferably feeding occurs at room temperature. The rollers pre-compact and degas the feed material and press it through the nozzle, forming a cylindrical strand. More specifically, the compaction mixture, serving as the feed material, is further compacted in the feed zone of the nozzle, which may be tapered, and begins to heat and sinter through friction on the nozzle surface, forming a slightly elongated (usually cylindrical) channel of the nozzle. The relevant surface of the nozzle is the surface of the nozzle's (usually cylindrical) channel along its minimum diameter. The minimum diameter of the nozzle is defined herein as the nozzle diameter. The pressing length is defined herein as the distance, where the minimum diameter of the cylindrical channel applies. The cylindrical channel of the nozzle can be extended after the pressing length, but the extended part of the cylindrical channel does not contribute to the friction of the feed material. The nozzle diameter and the pressing length are parameters that affect the degree of sintering. The strands are crushed to obtain pellets, for example, using a cutting knife as a crushing device at an adjusted distance from the outside of the mold. The cutting knife cuts or breaks the strands into pellets, wherein the length variation is generally 1-3 times the nozzle diameter. Subsequently, the pellets are cooled and can be sieved, for example, using a 1.6 mm sieve, which is performed in a vibrating screen. The sieved fine particle portion, which is essentially composed of the compacted mixture in a partially compacted form, can be directly reused as feed material or reused after grinding. A more detailed description is provided in Section E) of the experimental section. It should be noted that two or more steps (A) can occur before step (B), that is, two or more pressings occur before the formed strands are crushed. The parameter for this is the distance between the end of the pressing length and the crushing device, such as the cutting knife.

[0120] Prior to step (A), the compaction mixture is fed into a section of a granulator comprising a die with a nozzle and rollers. Preferably, the compaction mixture is fed into the granulator in powder form. This preferably occurs by gravity.

[0121] Preference is given to a method of making pellets, wherein the method comprises the step (Pre-A) of feeding the compaction mixture into a pelletizer, wherein the compaction mixture is in powder form, and step (Pre-A) occurs before step (A).

[0122] The formed strand has a surface temperature that increases relative to the ambient temperature after leaving the nozzle due to the friction that occurs. The surface temperature of the strand is determined, for example, by measuring its infrared radiation. Preferably, the strand surface temperature is greater than 50°C and less than 110°C, very preferably greater than 55°C and less than 105°C, in particular greater than 60°C and less than 103°C, and very particularly greater than 62°C and less than 101°C.

[0123] A method of producing pellets wherein the strands have a surface temperature greater than 50°C and less than 110°C is preferred.

[0124] Preferably, the pelletizer is a ring die pelletizer or a flat die pelletizer. In the case of a gear type pelletizer, two gears act as rollers and a spur gear transmission situation between the gears forms a nozzle and die equivalent, which results in compression and compaction of the compaction mixture.

[0125] Preference is given to a method for producing pellets, wherein the pelletizer is a ring die pelletizer, wherein the die has the geometric form of a ring with an inner side and an outer side, and the nozzle represents a passage from the inner side to the outer side, or the pelletizer is a flat die pelletizer, wherein the die has the geometric form of a flat plate with an upper side and a lower side, and the nozzle represents a passage from the upper side to the lower side.

[0126] A method of producing pellets is preferred wherein, in the case of a ring die pelletizer, the ring rotates and the roller has a fixed axis of rotation, and in the case of a flat die pelletizer, the die is fixed and the roller has a rotating axis of rotation.

[0127] The amount of mechanical energy input is primarily influenced by the ratio of the press length of the nozzle to the nozzle diameter. For example, the surface temperature is influenced by the selected press length and nozzle diameter of the nozzle. Preferably, the ratio of press length to nozzle diameter is 2-8, very preferably 3-7, in particular 4-6, and very particularly 5.

[0128] Preferred is a method of making pellets, wherein the nozzle has a nozzle diameter and a pressing length, and the ratio of the pressing length to the nozzle diameter is 2-8.

[0129] The rollers, preferably two or more rollers, very preferably two or three rollers, are generally driven by friction between the rollers, the compacting mixture, and the die. A smooth roller surface can lead to roller slippage. Excessive slippage, which can lead to failure of the production process, is reduced by a corrugated roller surface.

[0130] A method of producing pellets is preferred wherein the roller surface is corrugated.

[0131] In the case of a ring die pelletizer, another factor affecting the amount of mechanical energy input is the rotation speed of the ring die or its rotation frequency.

[0132] A method for producing pellets is preferred, wherein the pelletizer is a ring die pelletizer.

[0133] The number of molds at the granulator is driven by its structural design and its engineering considerations. Preferably, the granulator includes a mold. The number of rollers at the granulator is driven by its structural design and its engineering considerations. A higher number of rollers allows, in the case of a mold with two or more nozzles (the nozzles are positioned relative to each other on the mold), steps (A) and (B) to occur more frequently at the granulator within a certain period of time. The granulator preferably comprises two or more rollers, very preferably 2, 3 or 4 rollers, particularly 2 or 3 rollers, very particularly 2 rollers. The number of nozzles at the mold is driven by its structural design and engineering considerations. The higher number of nozzles at the mold enables step (A) to occur at a parallel separate nozzle or thereafter, which results in the formation of two or more parallel strands. Hereinafter, it is meant that step (A) occurs at another nozzle before step (A) is repeated again at the initial first nozzle. Then step (B) occurs in principle in parallel, i.e., the comminution of two or more strands occurs in principle in parallel. Therefore, in principle, two or more pellets are obtained in parallel. Thus, the output of the number of pellets per a certain period of time is significantly increased. The die of the pelletizer preferably comprises two or more nozzles, very preferably 48-20,000, in particular 96-16,000, very particularly 360-14,000, especially 720-12,000, very particularly 1,440-11,000, most particularly 3,600-10,000.

[0134] A method of producing pellets is preferred wherein the pelletizer comprises two rollers.

[0135] A method of producing pellets is preferred, wherein the pelletizer comprises a ring having two or more nozzles.

[0136] A method of making pellets is preferred wherein the pelletizer comprises a ring.

[0137] A method of making pellets is preferred wherein the pelletizer comprises two or more rollers and the die comprises two or more nozzles.

[0138] Preferred is a method of making pellets wherein the pelletizer comprises a die, two or more rollers and the die comprises two or more nozzles.

[0139] Preference is given to a method of making pellets wherein the pelletizer comprises a die, two or more rollers and the die comprises two or more nozzles and step (A) occurs at a first of the two or more nozzles and simultaneously or thereafter at a second of the two or more nozzles but before step (A) again occurs at the first of the two or more nozzles.

[0140] The pellets obtainable by the compaction process include

[0141] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and

[0142] (ii) 3-13 wt% of a processing aid, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0143] And weight % is based on the weight of the pellets.

[0144] The weight percent of components (i) and (ii) of the pellet is based on the weight of the pellet. Therefore, the weight percent of all components contained in the pellet (including components (i) and (ii)) totals 100 weight percent. In other words, the sum of all components is 100 weight percent. The sum of components (i) and (ii) is less than or equal to 100 weight percent.

[0145] Preferably, the pellets comprise (i) 87-97 wt% of a polymer stabilizer which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0146] (ii) 3-13 wt% of a processing aid, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0147] (iii) up to 10% by weight of other ingredients, which are different from components (i) and (ii),

[0148] And the sum of components (i), (ii) and (iii) is less than or equal to 100% by weight.

[0149] Preferably, the pellets consist of:

[0150] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0151] (ii) 3-13 wt% of a processing aid, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0152] (iii) 0-10% by weight of other ingredients, which are different from components (i) and (ii),

[0153] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0154] The pellets preferably have a round rod shape. While the round rod shape is idealized as a cylinder, the two bases of a cylinder are not always planar and parallel to each other in the case of pellets, and in particular, they are not planar and parallel to each other. This is due to the comminution of the strands during step (B), which contains more comminution components than when the strands, uniformly heated to a temperature above 110°C, are thermally cut with a knife. The round rod has a circular diameter. Preferably, the round rod has a circular diameter between 2 mm and 4 mm, very preferably 3 mm. The length of the pellets herein is understood to mean the longest distance in the direction of strand formation in the nozzle, i.e., the axis of the pellet, defined by averaging the same distance from points on the pellet surface (excluding those points on the pellet surface generated by comminuting the strands). In the case of a round rod, the axis of the pellet is the axis of rotation of the round rod. The pellets preferably have a length of 1-3 times the diameter of the circle. While a pellet has its own specific length value, multiple pellets may have an average length of the pellets. This is caused by step (B), which occurs by cutting with comminution components. The design of the nozzle and its nozzle channel plays a role in the distance of the comminution device in step (B). One option is to have the nozzle's pressing length followed by a portion having a diameter greater than the nozzle's diameter. Therefore, the nozzle includes a channel having a pressing length portion and an extension portion, with the extension portion following the pressing length portion. The extension portion allows the desired thickness of the mold to be greater than the nozzle's pressing length. A specific mold thickness may be desirable for reasons of mechanical strength (e.g., to avoid damage to the mold).

[0155] A possible step (C) is to sieve the granules from step (B), for example using a 1.6 mm sieve. This removes fines originating from the process of making the granules, for example during step (B) thereof.

[0156] A possible step (D) is cooling of the pellets. For example, cooling results in a pellet temperature that is similar to the temperature of the pelletizer surroundings. The temperature of the pelletizer surroundings is preferably room temperature, very preferably 23° C. This cooling can already take place partially or completely while a possible step (C) is being carried out. Cooling can be assisted by air flow.

[0157] The above definitions and preferences for the method for producing granules in a granulator, the compaction mixture and the granules are described with respect to the method for producing granules in a granulator. These definitions and preferences also apply to the other embodiments of the present invention.

[0158] Another embodiment of the present invention is a compaction mixture comprising

[0159] (i) 87-97 wt% of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and

[0160] (ii) 3 to 13% by weight of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0161] And the weight % is based on the weight of the compacted mixture.

[0162] The weight percent of components (i) and (ii) of the compacting mixture is based on the weight of the compacting mixture. Therefore, the weight percent of all components contained in the compacting mixture (including components (i) and (ii)) totals 100 weight percent. In other words, the sum of all components is 100 weight percent. The sum of components (i) and (ii) is less than or equal to 100 weight percent.

[0163] Preferably, the compaction mixture comprises

[0164] (i) 87-97% by weight of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0165] (ii) 3-13 wt% of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0166] (iii) up to 10% by weight of other ingredients, which are different from components (i) and (ii),

[0167] And the sum of components (i), (ii) and (iii) is less than or equal to 100% by weight.

[0168] Preferably, the compaction mixture consists of:

[0169] (i) 87-97% by weight of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0170] (ii) 3-13 wt% of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0171] (iii) 0-10% by weight of other ingredients, which are different from components (i) and (ii),

[0172] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0173] Preferably the mixture for compaction is in powder form.

[0174] Another embodiment of the present invention is a pellet comprising

[0175] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and

[0176] (ii) 3-13 wt% of a processing aid, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0177] And weight % is based on the weight of the pellets.

[0178] The weight percent of components (i) and (ii) of the pellet is based on the weight of the pellet. Therefore, the weight percent of all components contained in the pellet (including components (i) and (ii)) totals 100 weight percent. In other words, the sum of all components is 100 weight percent. The sum of components (i) and (ii) is less than or equal to 100 weight percent.

[0179] Preferably, the pellets comprise:

[0180] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0181] (ii) 3 to 13 wt% of a processing aid which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0182] (iii) up to 10% by weight of other ingredients, which are different from components (i) and (ii),

[0183] And the sum of components (i), (ii) and (iii) is less than or equal to 100% by weight.

[0184] Preferably, the pellets consist of:

[0185] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0186] (ii) 3 to 13 wt% of a processing aid which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0187] (iii) 0-10% by weight of other ingredients, which are different from components (i) and (ii),

[0188] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0189] Pellets are preferred, which have the shape of round rods and the round rods have a diameter of a circle of 2 to 4 mm.

[0190] Pellets are preferred, which have a length of 1 to 3 times the diameter of a circle.

[0191] Another embodiment of the present invention is a method for producing a stabilized polymer comprising the steps of:

[0192] (AP) adding the pellets to the polymer to obtain a pellet-polymer mixture,

[0193] (BP) exposing the pellet-polymer mixture to a temperature in the range of 120-340° C. under mechanical stirring to obtain a stabilized polymer,

[0194] Wherein the polymer is polyolefin, polystyrene or a mixture thereof,

[0195] The pellets include:

[0196] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and

[0197] (ii) 3-13 wt% of a processing aid, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0198] And weight % is based on the weight of the pellets.

[0199] The weight percent of components (i) and (ii) of the pellet is based on the weight of the pellet. Therefore, the weight percent of all components contained in the pellet (including components (i) and (ii)) totals 100 weight percent. In other words, the sum of all components is 100 weight percent. The sum of components (i) and (ii) is less than or equal to 100 weight percent.

[0200] Preferably, when used in the process for producing a stabilized polymer, the pellets comprise

[0201] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0202] (ii) 3 to 13 wt% of a processing aid which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0203] (iii) up to 10% by weight of other ingredients, which are different from components (i) and (ii),

[0204] And the sum of components (i), (ii) and (iii) is less than or equal to 100% by weight.

[0205] Preferably, when used in the process for producing stabilized polymers, the pellets consist of:

[0206] (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0207] (ii) 3 to 13 wt% of a processing aid which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, and

[0208] (iii) 0-10% by weight of other ingredients, which are different from components (i) and (ii),

[0209] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0210] In step (AP), the pellets are preferably of a well-fitting size, as overly large pellets are more difficult to feed, blend and disperse in the polymer.

[0211] In step (BP), the pellet components are uniformly distributed and / or dissolved in the polymer to be stabilized under mechanical stirring. This is assisted by exposing the pellet-polymer mixture to heat, which, on the one hand, reduces the viscosity of the polymer and, on the other hand, melts the pellet components if the corresponding melting range of the components is 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, especially 200°C to 280°C, and very particularly 210°C to 260°C.

[0212] Polyolefins are, for example:

[0213] 1. Homopolymers of monoolefins and dienes, for example polypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene, polyvinylcyclohexane, polyisoprene or polybutadiene and polymers of cyclic olefins, for example cyclopentene or norbornene, polyethylene, for example high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or mixtures thereof, for example mixtures of polypropylene with polyisobutylene, mixtures of polypropylene with polyethylene (for example PP / HDPE, PP / LDPE) or mixtures of different types of polyethylene (for example LDPE / HDPE).

[0214] 2. Copolymers of monoolefins or diolefins with each other or with other vinyl monomers, for example 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, for example ethylene / norbornene such as COC, ethylene / 1-olefin copolymers, where the 1-olefin is generated in situ; propylene / butadiene copolymers, isobutylene / isoprene copolymers, Ethylene / vinylcyclohexane copolymers, ethylene / alkyl acrylate copolymers, ethylene / alkyl methacrylate copolymers, ethylene / vinyl acetate copolymers or ethylene / acrylic acid copolymers and salts thereof (ionomers) and terpolymers of ethylene with propylene and a diene, such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of these copolymers with one another or with other polyolefins, for example polypropylene / ethylene-propylene copolymers, LDPE / ethylene-vinyl acetate copolymers (EVA) or LDPE / ethylene-acrylic acid copolymers (EAA).

[0215] Monoolefin polyolefins, preferably polyethylene and polypropylene, can be prepared by various and especially by the following processes:

[0216] a) Free radical polymerization (usually under high pressure and at elevated temperature)

[0217] b) Catalytic polymerization using a catalyst containing one or more metals, typically from Groups 4, 5, 6 (e.g., chromium), or 7 of the Periodic Table. These metals typically have one or more ligands, typically oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls, and / or aryls, which may be π- or σ-coordinated. These metal complexes may be in free form or immobilized on a substrate, typically activated magnesium chloride, titanium(III) chloride, aluminum oxide, or silicon oxide. These catalysts may be soluble or insoluble in the polymerization medium. The catalysts may be used in the polymerization by themselves or with other activators, typically metal alkyls, metal hydrides, alkyl metal halides, alkyl metal oxides, or metal alkoxanes, where the metal is an element from Groups 1, 2, and / or 3 of the Periodic Table. The activators may be conveniently modified with other ester, ether, amine, or silyl ether groups. These catalyst bodies are commonly referred to as Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene, or single site catalysts (SSC).

[0218] Polystyrene is for example:

[0219] 1. Homopolymer of styrene.

[0220] 2. Copolymers of styrene with comonomers such as ethylene, propylene, dienes, nitriles, acids, maleic anhydride, maleimides, vinyl acetate, acrylic acid derivatives and mixtures thereof, for example styrene / butadiene, styrene / acrylonitrile, styrene / ethylene, styrene / alkyl methacrylates, styrene / butadiene / alkyl acrylates, styrene / butadiene / alkyl methacrylates, 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.

[0221] 3. Graft copolymers of styrene, for example styrene grafted onto polybutadiene, styrene grafted onto polybutadiene-styrene or polybutadiene-acrylonitrile copolymers, styrene and acrylonitrile grafted onto polybutadiene, styrene, acrylonitrile and methyl methacrylate grafted onto polybutadiene, styrene and maleic anhydride grafted onto polybutadiene, styrene, acrylonitrile and maleimide grafted onto polybutadiene, styrene and maleimide grafted onto polybutadiene, styrene and an alkyl acrylate or methacrylate other than methyl acrylate grafted onto polybutadiene, styrene and acrylonitrile grafted onto ethylene / propylene / diene terpolymers, styrene and acrylonitrile grafted onto polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile grafted onto acrylate / butadiene copolymers.

[0222] In the case of polyolefin copolymers, at least two different monomers are copolymerized. Preference is given to polyolefin copolymers in which the weight content of the polymerized olefin monomer exceeds 50%, based on the weight of all polymerized monomers. In the case of polystyrene copolymers, at least two different monomers are copolymerized or one monomer is grafted onto at least one already polymerized different monomer. Preference is given to polystyrene copolymers in which the weight content of the polymerized or grafted styrene exceeds 50%, based on the weight of all polymerized or grafted monomers.

[0223] Preferably, the polymer being polyolefin, polystyrene or a mixture thereof is thermoplastic, ie it can be formed into a new form at elevated temperature, for example in the range of 120 to 340°C, in particular 135 to 330°C.

[0224] Polymers that are polyolefins, polystyrenes or mixtures thereof are susceptible to oxidative, thermal or light-induced degradation.

[0225] The amount of pellets to be added of a polymer that is a polyolefin, polystyrene or a mixture thereof varies depending on the specific polymer and the desired degree of protection against oxidative, thermal or light-induced degradation. Preferably, the amount of pellets expressed in wt. %, based on the weight of the polymer, is 0.01 to 5 wt. %, very preferably 0.02 to 3 wt. %, in particular 0.04 to 2 wt. %, very particularly 0.05 to 1 wt. %, especially 0.08 to 0.8 wt. %, and very particularly 0.1 to 0.4 wt. %.

[0226] Preference is given to a process for producing stabilized polymers, wherein step (BP) takes place in an extruder or a co-kneader.

[0227] In step (AP), the pellets can be added to the polymer, which already has a polymer temperature in the range of 120 to 340°C. For example, the pellets can be added to the polymer, which has already been warmed in an extruder or co-kneader. For example, the pellets can be introduced into the already warmed and viscous polymer to be stabilized via a feeder, such as an extruder. As a result, the pellet-polymer mixture immediately has a polymer temperature in the range of 120-340°C, and the pellets begin to disintegrate.

[0228] Preference is given to a process for producing a stabilized polymer, wherein the polymer added to the pellets in step (AP) has a polymer temperature in the range of 120-340°C.

[0229] In step (AP), the pellets can be added to a polymer having a polymer temperature below 40°C. When the polymer is in pellet form, a pellet-polymer mixture is produced comprising the components (a) pellets and (b) polymer pellets. The polymer pellets have, for example, a cylindrical geometry and are obtained, for example, by thermally cutting a warm extruded polymer strand and then cooling it in a water quench. The pellet-polymer mixture obtained in step (AP), wherein the polymer is in pellet form, can be prepared and stored independently of step (BP) or can be prepared directly before step (BP).

[0230] Preference is given to a process for producing stabilized polymers, wherein the polymer added to the pellets in step (AP) is present in pellet form and has a polymer temperature of less than 40°C.

[0231] The definitions and preferences described for the process of producing or applying to the stabilized polymer also apply to the other embodiments of the present invention.

[0232] A further embodiment of the present invention is the use of the pellets for the dust-free processing of components thereof in the production of stabilized polymers, wherein the polymer is a polyolefin, polystyrene or a mixture thereof and wherein the pellets comprise:

[0233] (i) 87-97 wt% of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and

[0234] (ii) 3 to 13% by weight of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0235] And weight % is based on the weight of the pellets.

[0236] The weight percent of components (i) and (ii) of the pellet is based on the weight of the pellet. Therefore, the weight percent of all components contained in the pellet (including components (i) and (ii)) totals 100 weight percent. In other words, the sum of all components is 100 weight percent. The sum of components (i) and (ii) is less than or equal to 100 weight percent.

[0237] Preferably, when the pellets are used for dust-free handling of components thereof in the manufacture of stabilized polymers, the pellets comprise:

[0238] (i) 87-97% by weight of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0239] (ii) 3 to 13% by weight of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0240] (iii) up to 10% by weight of other ingredients, which are different from components (i) and (ii),

[0241] And the sum of components (i), (ii) and (iii) is less than or equal to 100% by weight.

[0242] Preferably, the pellets are used for dust-free handling of components thereof in the manufacture of stabilized polymers and consist of:

[0243] (i) 87-97% by weight of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4),

[0244] (ii) 3 to 13% by weight of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa,

[0245] (iii) 0-10% by weight of other ingredients, which are different from components (i) and (ii),

[0246] And the sum of components (i), (ii) and (iii) is 100% by weight.

[0247] Figure 1 The pellets obtained from Example E-1-1 are shown placed on millimeter paper.

[0248] Figure 2 The pellets obtained from Example E-1-2 are shown placed on graph paper.

[0249] Figure 3 The pellets obtained from Example E-1-3 are shown placed on graph paper.

[0250] Figure 4 The pellets obtained from Example E-1-4 are shown placed on graph paper.

[0251] Figure 5 The pellets obtained from Example E-1-5 are shown placed on graph paper.

[0252] Figure 6 The pellets obtained from Example E-1-6 are shown placed on graph paper.

[0253] Figure 7 The pellets obtained from Example E-1-7 are shown placed on graph paper.

[0254] Figure 8 The pellets obtained from Example E-1-8 are shown placed on graph paper.

[0255] The following examples further illustrate the present invention without limiting the present invention. Unless otherwise specified, percentage values ​​are % by weight.

[0256] A) Characterization methods

[0257] If not specified otherwise, the average particle size is determined by digital pattern analysis using a Camsizer P4 from Retsch Technology GmbH. The measuring principle is dynamic pattern analysis in accordance with ISO 13322-2.

[0258] Bulk density is measured in accordance with DIN EN ISO 17892-3.

[0259] The melt flow index of a polymer is measured according to ISO 1133 on a Goettfert MI-Robo using the specified parameters.

[0260] Differential scanning calorimetry (DSC) was measured at atmospheric pressure according to EN ISO 11357-3. The thermal cycles were (a) 0°C to 200°C at 10°C / min and 30 mL / min N₂, (b) 200°C to 0°C at 10°C / min and 30 mL / min N₂, and (c) 0°C to 200°C at 10°C / min and 30 mL / min N₂. The melting range, peak melting temperature, and melting enthalpy were determined under thermal cycle (c).

[0261] High temperature gel permeation chromatography (HT-GPC) is measured according to ISO 16014-4. An Agilent PL-GPC 220 with an RI detector is used as an apparatus. An Agilent PFgel Olexis Guard 50x 7.5mm post (part number PL1110-1400) is used as a precolumn. Three Agilent PLgel Olexis 13 μm 300x7.5mm posts (part number PL1110-6400) are used as posts. The column temperature is 150°C. The calibration standard is polystyrene and High EasiVial GPC / SEC calibration standard (part number PL2010-0201 and part number PL2010-0202) from Agilent. Trichlorobenzene is used as an eluent with a flow rate of 1 mL / min, a sample concentration of 3 mg / mL, and an injection volume of 200 μL. The measured number average molecular weight Mn and the measured weight average molecular weight Mw are used to calculate the polydispersity index (PD) as the ratio of Mw to Mn.

[0262] The sieving analysis was carried out by digital pattern analysis using a Camsizer P4 from Retsch Technology GmbH. The measuring principle was dynamic pattern analysis according to ISO 13322-2) with D10, D50 and D90 values.

[0263] The Norner abrasion test involves mechanically treating the tested form using a vibrating sieve shaker and glass beads. An initial sieve analysis is performed for one minute, followed by further sieving using glass beads on the sieve plate to mechanically influence the material. The change in the sieve fraction after 5, 10, and 20 minutes is measured. The sieves used are, from bottom to top, 200 μm, 500 μm, 1 mm, 1.6 mm, 2.5 mm, and 4 mm. The glass beads used (Sigmund Lindner GmbH, Type P) are 16 mm ± 0.02 mm, weigh 5.36 g per bead, and are made of soda-lime glass with a fine matte surface.

[0264] The test procedure is as follows:

[0265] 1. Add 50 g of sample to a sieve shaker without glass beads and sieve for 1 minute with an amplitude of 1 mm. Measure the mass on each sieve plate and sieve pan.

[0266] 2. Add 8 glass balls to a 500 μm sieve; 9 glass balls to a 1.0 mm sieve, 10 glass balls to a 1.6 mm sieve, and 11 glass balls to a 2.5 mm sieve. Continue sieving for 5 minutes, then measure the mass on each sieve plate and sieve pan.

[0267] 3. Continue sieving for another 5 minutes and repeat the weighing procedure.

[0268] 4. Continue sieving for another 10 minutes and repeat the weighing procedure.

[0269] A Retsch Sieve Shaker AS 200 control from the company Retsch GmbH serves as sieve shaker.

[0270] Total fines is the sum of all material collected by the base plate and the 200 μm mesh. Thus, sample fragments (<500 μm) generated under abrasive stress and falling through the 500 μm mesh are considered fines. The particle size fraction (in wt%) <500 μm after 20 minutes is an important indicator for determining the abrasion and impact resistance of the tested form (Norner value). The results can range from an extremely stable 0% to an extremely unstable 100%.

[0271] The average weight of the pellets is measured by taking a certain number of pellets (about 45 pellets), weighing the certain number of pellets to obtain a total weight and dividing the total weight by the certain number of pellets.

[0272] The average length of the pellets was calculated by multiplying the average weight of the pellets by 0.95 g / cm 3 The assumed density is calculated by dividing by the circular area of ​​a circle having a pellet diameter of 3 mm.

[0273] B) Starting Materials

[0274] SM-PS-1: Irgafos 168

[0275] Irgafos 168 (TM, available from BASF SE, melting point 180-183° C.), which contains tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4) as depicted below in powder form, i.e., a loose bulk material having a bulk density of 467 g / L and an average particle size of 400 μm.

[0276]

[0277] SM-PA-1: Licocene PP 1302

[0278] Licocene PP 1302 (TM, available from Clariant in the commercial technical form of fine granules) is a propylene-ethylene copolymer wax (CAS No. 9010-79-1) synthesized from propylene and ethylene using a metallocene catalyst. The long polymer chains are branched via short (-CH3) chains. Some physicochemical properties were measured and are described in Table B-1.

[0279] The technical data sheet states a density of 0.87 g / cm² at 23°C according to ISO 1183. 3 .

[0280] The technical data sheet states a dropping point according to ASTM D 3954 of 87-93°C.

[0281] The technical data sheet states a viscosity of 150-250 mPas according to DIN 53019 at 170°C.

[0282] The sieve analysis of the material in its technical form of fine particles was measured and is described in Table B-2. The bulk density was measured to be 338 g / L. The material in its technical form of fine particles was used for compaction.

[0283] SM-PA-2: Petrolite EP-700

[0284] Petrolite EP-700 (TM, available from Baker Hughes) is a propylene-ethylene copolymer wax (CAS-No. 9010-79-1). Controllable branching of the long polymer chains occurs through short chains (-CH3) derived from propylene. Some physicochemical properties were measured and are described in Table B-1.

[0285] The technical data sheet states a drop melting point of 96°C according to ASTM D-127.

[0286] The technical data sheet states a viscosity of 12 pcs (120 mPas) at 99°C.

[0287] Petrolite EP-700 was ground in a Pallmann disc mill PF 300. The sieve analysis of the ground material obtained was measured and is described in Table B-2. The bulk density of the ground material was measured to be 473 g / L. The ground material was used for compaction.

[0288] SM-PA-3: Luwax AL-3

[0289] Luwax AL-3 (TM, available as a powder from BASF) is a polyethylene wax (CAS-No. 9002-88-4) synthesized by high pressure polymerization. The long polymer chains are branched by long chains (-[CH2-CH2-] n Some physicochemical properties were measured and described in Table B-1.

[0290] The technical data sheet states a density of 0.91-0.925 g / cm² at 23°C according to DIN 53479 and ASTM D-792. 3 .

[0291] The technical data sheet states a dropping point (Ubbelohde) of 101-112° C. according to DIN 51801 and ASTM D-3954.

[0292] The technical data sheet states a melting point (DSC) of 102-108°C according to DIN 51007 and ASTM D-3418.

[0293] The technical data sheet states a melt viscosity of 135-240 mm2 at 120°C according to DIN 51562 and ASTM D-2162. 2 / s.

[0294] The sieve analysis of the material in its technical form of powder was measured and is described in Table B-2. The bulk density was measured to be 495 g / L. The material in its technical form was used for compaction.

[0295] SM-PA-4: Dow PG 7008

[0296] Dow PG 7008 (TM, available from Dow Chemicals) is a low density polyethylene (CAS-No. 9002-88-4). Some physico-chemical properties were measured and are described in Table B-1.

[0297] The technical data sheet states a density of 0.918 g / cm² at 23°C according to ASTM D-792. 3 .

[0298] The technical data sheet states a melting temperature (DSC) of 106°C.

[0299] The technical data sheet states a Vicat softening temperature according to ISO 306 / A of 89.0°C.

[0300] The technical data sheet states a melt index according to ISO 1133 (190°C / 2.16 kg) of 7.7 g / 10 min.

[0301] Dow PG 7008 was ground in a Pallmann disc mill PF 300. The sieve analysis of the ground material obtained was measured and is described in Table B-2. The bulk density of the ground material was measured to be 285 g / L. The ground material was used for compaction.

[0302] SM-PA-5: Borflow HL 708FB

[0303] Borflow HL 708FB (TM, available from Borealis) is a polypropylene (CAS-No. 9003-07-0). Some physico-chemical properties were measured and are described in Table B-1.

[0304] The technical data sheet states a melting temperature (DSC) of 158°C.

[0305] The technical data sheet states a melt index according to ISO 1133 (130°C / 2.16 kg) of 800 g / 10 min.

[0306] Borflow HL 708FB was ground in a Pallmann disc mill PF 300. The sieve analysis of the ground material obtained was measured and is described in Table B-2. The bulk density of the ground material was measured to be 365 g / L. The ground material was used for compaction.

[0307] Table B-1: Measured physico-chemical properties of starting material processing aids

[0308]

[0309] Table B-2: Sieve Analysis

[0310]

[0311]

[0312] C) Preparation of the mixture for compaction

[0313] A compaction mixture consisting of polymer stabilizer and processing aid was prepared by blending the starting materials described in Table C-1 in a 100-L MTI blender at room temperature for 5 minutes.

[0314] Table C-1: Mixtures for Compaction

[0315]

[0316] Food notes: a) The present invention

[0317] b) Contrast

[0318] c) at room temperature and atmospheric pressure

[0319] D) Flakes compacted by rollers

[0320] For example, in D-1-1, the starting material SM-PS-1 (100%) was compacted and aggregated via a roller compaction process to obtain comparative flakes. SM-PS-1, in powder form, was forced into the compaction zone via a screw feeder in a hopper. The compaction zone was formed by the remaining gap between two rollers with lightly scored surfaces, which rotated toward each other. The rollers were cooled with cold water to maintain the temperature close to room temperature. A suitable laboratory roller compactor is, for example, the model WP50N / 75 from Alexanderwerk GmbH, Germany (roller diameter: 150 mm, roller length: 75 mm, maximum compaction capacity: 12.8 t, maximum linear load: 1.71 t / cm). The compacted starting material, which exited the compaction zone in the form of plates, was granulated via a sieve granulator with a 1.6 mm sieve (e.g., model GLA-ORV-0215 ​​from Frewitt Ltd, Switzerland) to form free-flowing flakes (= flakes of D-1-1). The sheets of D-1-1 were subjected to Norner abrasion testing and the results are described in Table E-1.

[0321] E) Pellets compacted by a ring die pelletizer

[0322] A ring die pelletizer (i.e., a Muench pelletizer RMP 250) was used for compaction tests of the materials described in Table E-1. The Muench ring die pelletizer is described, for example, in the article "Product gestaltungüber mechanisches Agglomerieren von Pulvern," W. Raehse, Chemie Ingeneur Technik, 2015, 87, No. 7, 881-902, Figure 18 on page 898. The Muench pelletizer RMP 250 has a rotatable ring die equipped with a nozzle, for example, with a nozzle diameter of 3 mm and a pressing length of 15 mm or 18 mm. The inner diameter of the ring die is 250 mm and its width is approximately 4 cm. A row of two or three nozzles is suitable for this width. The nozzles extend to the inside of the ring die at an angle of 60°. The nozzle diameter is defined herein as the minimum diameter of the cylindrical channel of the nozzle, and the pressing length is the distance where the minimum diameter applies. The cylindrical channel of the nozzle can be extended beyond the pressing length, but the extended portion of the cylindrical channel does not contribute to friction through the material being compacted. Here, the nozzle channel is unextended. Specific applicable nozzle diameters and pressing lengths are listed in Table E-1. The compacting material is gravity-fed at room temperature via a single-volume screw feeder positioned above the pellet pressing section of the ring die pelletizer. This section comprises a die with its nozzle and two rollers. The rollers (each 96 mm in diameter and 30 mm in width) have a corrugated surface. In the pellet pressing section, the two rollers push the material into the nozzle of the rotating ring die, where the material is compacted and heated by shear forces to a temperature at which the processing aid begins to soften. During the sintering process, the compacted material is granulated into cylindrical pellets. To begin the process, the ring die is set to a circumferential speed of approximately 4 m / s at the inner surface of the ring die (i.e., at a distance of 12.5 cm from the die's axis of rotation). The compacting material is fed into the pressing section as a powder. An initial start-up period of approximately 15 minutes is necessary until stable operation of the process is achieved. Although the powder of the compacting material initially flows through the nozzle, this can change towards the formation of strands when some compacting material and the ring die, rollers, and nozzle reach a stable temperature. For compacting material, excessively high temperatures can lead to the formation of a pasty mass, which blocks further feeding of the compacting material. At the nozzle outlet, the strands are cut / broken by two knives, which have an adjustable distance from the ring die to the pellets and a length of approximately 1 to 3 times the diameter of the pellets, i.e., approximately 3 mm to 9 mm. Ideally, the change in length is minimal, but some variation is unavoidable due to the cutting / broken. Table E-1 states whether pellets were obtained and therefore whether strands were formed. Once the process is running stably, the temperature of the material leaving the nozzle in the mold is measured by an IR temperature sensor via contactless measurement of the emitted IR radiation and is stated in Table E-1 as the surface temperature of the strands.Statistically, the IR radiation emitted by the outer surface of the ring is also included. However, when the process is running stably, the ring die has warmed to a temperature close to the surface temperature of the strand. The ring die itself is not heated (except for Example E-1-4) or cooled, but is subjected to warming due to the friction of the compacting material. The pellets obtained are sieved with a 1.6 mm sieve (200 mm diameter vibrating test sieve) to separate fines from the pellets obtained. The amount of fines removed by sieving is stated in Table E-1, based on the total amount of compacting material. The removed fines can be directly reused as material to be compacted. The pellets have cooled to room temperature. If pellets are obtained, a Norner wear test of the pellets after sieving is performed and the results are described in Table E-1. Further characterization of the pellets obtained is described in Table E-2. Figures 1 to 8 Depicting pictures of pellets obtained under Examples E-1-1 to E-1-8.

[0323] Table E-1: Compaction and wear test results of ring die pelletizer

[0324]

[0325]

[0326] Data Notes: a) The present invention

[0327] b) Contrast

[0328] c) Example of roller compaction as described under D)

[0329] d) Nozzle diameter x pressing length

[0330] e) Deviating from the general procedure, the nozzle and ring were initially preheated to 120°C before the initial start-up period to reduce the start-up period time, however, the process ran unstable with a lower flux than other Examples E-1-1 to E-1-8.

[0331] From the results in Table E-1:

[0332] - Example D-1-1 shows that SM-PS-1 (Irgafos 168) can be cold compacted into thin sheets, but the sheets give poor results in the Norner abrasion test;

[0333] Example E-1-4 shows that SM-PS-1 (Irgafos 168) without a processing aid requires special preheating for pelletization in a ring die pelletizer. This leads to the conclusion that SM-PS-1 itself has a too high melting point and requires a processing aid as a binder to allow the formation of stable pellets.

[0334] Example E-1-2 shows relative to Example E-1-3 that a higher die length leads to a higher process temperature due to more friction, which however does not lead to better Norner wear test results;

[0335] Example E-1-3 shows relative to Example E-1-4 that SM-PA-1 (Licocene 1302) leads to pellets with significantly better Norner abrasion test results than without the processing aid;

[0336] Example E-1-2 shows, relative to Example E-1-5, that SM-PA-1 (Licocene 1302) leads to 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;

[0337] - Examples E-1-5 and E-1-8 show that the amount of fines generated in the process itself and removed by the 1.6 mm sieve is not a reliable indicator of a beneficial Norner abrasion test result.

[0338] Table E-2: Pellet Characterization

[0339]

[0340]

[0341] Data Notes: a) The present invention

[0342] b) Contrast

[0343] c) Caused by the diameter of the nozzle

[0344] d) Calculated from the average pellet weight

[0345] e) Describe the results from Table E-1 again

[0346] From the results in Table E-2:

[0347] Example E-1-4 shows that SM-PS-1 without processing aid leads only to pellets with a low average weight;

[0348] - Example E-1-7 shows that a high average weight is not a reliable indicator of a favorable Norner abrasion test result;

[0349] - The pellets obtained look quite similar in the pictures, unlike the pellets obtained in Example E-1-4, and are not a reliable indicator of a beneficial Norner abrasion test result.

Claims

1. A method for producing pellets in a pelletizer comprising a roller and a die having a nozzle, the method comprising the following steps: (A) pressing the compaction mixture by rollers through nozzles to obtain strands, and (B) crushing the strands to obtain pellets, wherein the compaction mixture comprises (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and (ii) 3 to 13 wt.% of a processing aid, which is a propylene-ethylene copolymer and which has a melting enthalpy of less than 100 J / g at 101.32 kPa, wherein the melting enthalpy is determined by differential scanning calorimetry according to EN ISO 11357-3, And the weight % is based on the weight of the compaction mixture.

2. The method according to claim 1, wherein the processing aid has a weight average molecular weight higher than 10,000 Da and lower than 40,000 Da. 3 . The method of claim 1 , wherein the processing aid has a melting peak temperature higher than 50° C. and lower than 85° C.

4. The method according to claim 2, wherein the processing aid has a melting peak temperature higher than 50°C and lower than 85°C.

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

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

7. The method of claim 1, wherein the processing aid is a propylene-ethylene copolymer that is a wax.

8. The method of claim 2, wherein the processing aid is a propylene-ethylene copolymer which is a wax.

9. The method of claim 3, wherein the processing aid is a propylene-ethylene copolymer which is a wax.

10. The method of claim 4, wherein the processing aid is a propylene-ethylene copolymer that is a wax.

11. The method of claim 5, wherein the processing aid is a propylene-ethylene copolymer that is a wax.

12. The method of claim 6, wherein the processing aid is a propylene-ethylene copolymer that is a wax.

13. The method of any one of claims 1 to 12, wherein the compaction mixture comprises (i) 89 to 96 weight percent of a polymer stabilizer, (ii) 4 to 11 weight percent of a processing aid.

14. The method according to any one of claims 1 to 12, wherein the strand has a surface temperature higher than 50°C and lower than 110°C.

15. The method of claim 13, wherein the strand has a surface temperature higher than 50°C and lower than 110°C.

16. The method according to any one of claims 1 to 12, wherein the method comprises the following steps: (Pre-A) The mixture for compaction is fed into a granulator, wherein the mixture for compaction is in the form of a powder, and step (Pre-A) occurs before step (A).

17. The method according to claim 15, wherein the method comprises the following steps: (Pre-A) The mixture for compaction is fed into a granulator, wherein the mixture for compaction is in the form of a powder, and step (Pre-A) occurs before step (A).

18. The method according to any one of claims 1 to 12, wherein the pelletizer is a ring die pelletizer, wherein the die has the geometric form of a ring with an inner side and an outer side and the nozzles represent a passage from the inner side to the outer side, or the pelletizer is a flat die pelletizer, wherein the die has the geometric form of a planar plate with an upper side and a lower side and the nozzles represent a passage from the upper side to the lower side.

19. The method according to claim 17, wherein the pelletizer is a ring die pelletizer, wherein the die has the geometric form of a ring with an inner side and an outer side and the nozzle represents a passage from the inner side to the outer side, or the pelletizer is a flat die pelletizer, wherein the die has the geometric form of a flat plate with an upper side and a lower side and the nozzle represents a passage from the upper side to the lower side.

20. The method of claim 18, wherein in the case of a ring die pelletizer, the ring rotates and the roller has a fixed axis of rotation, and in the case of a flat die pelletizer, the die is fixed and the roller has a rotating axis of rotation.

21. The method of claim 19, wherein in the case of a ring die pelletizer, the ring rotates and the roller has a fixed axis of rotation, and in the case of a flat die pelletizer, the die is fixed and the roller has a rotating axis of rotation.

22. The method of any one of claims 1-12, wherein the nozzle has a nozzle diameter and a pressing length, and a ratio of the pressing length to the nozzle diameter is 2-8.

23. The method of any one of claims 19-21, wherein the nozzle has a nozzle diameter and a pressing length, and the ratio of the pressing length to the nozzle diameter is 2-8.

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

25. The method of claim 23, wherein the roller surface is corrugated.

26. The method according to any one of claims 1 to 12, wherein the pelletizer is a ring die pelletizer.

27. The method according to claim 25, wherein the pelletizer is a ring die pelletizer.

28. The method of any one of claims 1-12, wherein the granulator comprises two or more rollers and the die comprises two or more nozzles.

29. The method of claim 27, wherein the granulator comprises two or more rollers and the die comprises two or more nozzles.

30. A pellet comprising: (i) 87-97 wt% of a polymer stabilizer, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and (ii) 3 to 13 wt.% of a processing aid, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, wherein the melting enthalpy is determined by differential scanning calorimetry according to EN ISO 11357-3, And weight % is based on the weight of the pellets.

31. The pellet according to claim 30, which has the shape of a round rod and the round rod has a diameter of a circle of 2-4 mm.

32. The pellet of claim 31 , having a length of 1 to 3 times the diameter of a circle.

33. Use of granules as defined in any one of claims 30 to 32 for the dust-free processing of components thereof in the manufacture of stabilized polymers, wherein the polymer is a polyolefin, polystyrene or a mixture thereof.

34. A method for producing a stabilized polymer comprising the steps of: (AP) adding pellets as defined in any one of claims 30 to 32 to a polymer to obtain a pellet-polymer mixture, (BP) exposing the pellet-polymer mixture to a temperature in the range of 120-340° C. under mechanical stirring to obtain a stabilized polymer, The polymer is polyolefin, polystyrene or a mixture thereof.

35. A compaction mixture comprising (i) 87-97 wt% of a polymer stabilizer in the physical form of a powder, which is tris(2,4-di-tert-butylphenyl) phosphite (CAS-No. 31570-04-4), and (ii) 3 to 13% by weight of a processing aid in the physical form of a powder, which is a propylene-ethylene copolymer having a melting enthalpy of less than 100 J / g at 101.32 kPa, wherein the melting enthalpy is determined by differential scanning calorimetry according to EN ISO 11357-3, And the weight % is based on the weight of the compacted mixture.

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