Renewable marine plastic material PA66 and preparation method thereof

Abstract

The invention relates to a renewable marine plastic material PA66 and a preparation method thereof, and belongs to the technical field of high polymer materials, the renewable marine plastic material comprises the following components by weight: 100 parts of modified nylon resin, 1.8-2.4 parts of zinc powder, 8-11 parts of a flexibilizer, 0.08-0.1 part of an antioxidant, and 1.2-1.5 parts of a lubricant; the modified nylon resin is prepared by the following steps: carrying out amine ester exchange on diallylamine and dimethyl 3, 3 '-dithiodipropionate to prepare an intermediate, carrying out click addition on mercaptoacetic acid and double bonds in the intermediate to prepare a modified monomer, and carrying out copolymerization on the modified monomer, adipic acid and hexamethylenediamine; the modified monomer introduces a disulfide bond with low bond energy into a polymerization chain, a sulfur-nitrogen structure in the structure forms a chelation effect, zinc powder particles are captured in the blending process, bond breaking of the disulfide bond is efficiently promoted in situ, the melting point of nylon 66 is effectively reduced, low-energy-consumption regeneration of the nylon 66 material is achieved, and recycling of the marine stranding nylon material is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and in particular, relates to a renewable marine plastic material PA66 and a preparation method thereof. Background Art

[0002] Marine waste plastics can be divided into stranded marine waste plastics, floating marine waste plastics and submerged marine waste plastics. Marine waste plastics and the microplastics they form have irreversible harm to marine life and human health. So far, more than 1,500 species are known to be affected by marine debris.

[0003] Among all the waste plastics in the ocean, stranded marine waste plastics have the highest proportion, accounting for more than 90% of the waste plastics in the ocean in terms of quantity. In terms of composition, stranded marine waste plastics include PA (nylon), PP (polypropylene), PE (polyethylene), etc., among which nylon accounts for a relatively high proportion. The recycling of nylon materials is an important way to solve the problem of marine plastics. In the existing technology, the recycling method for nylon materials is still mainly heat recovery. However, the melting point of nylon materials is relatively high, and the energy consumption of melt regeneration is high, resulting in high recycling costs for nylon materials, which seriously restricts the promotion of the nylon marine plastic recycling industry. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a renewable marine plastic material PA66 and a preparation method thereof.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A renewable marine plastic material PA66, comprising, by weight:

[0007] 100 parts of modified nylon resin, 1.8-2.4 parts of zinc powder, 8-11 parts of toughening agent, 0.08-0.1 parts of antioxidant and 1.2-1.5 parts of lubricant;

[0008] The modified nylon resin is prepared by the following method:

[0009] Step A1: dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran are mixed, nitrogen is introduced for protection, the temperature is raised to 60-70°C, stirring is applied at 120-180 rpm, reflux reaction is carried out for 2.5-3.5 hours, and after the reaction is completed, tetrahydrofuran is removed by rotary evaporation, and then washed with water and vacuum dried to obtain an intermediate;

[0010] Further, the dosage ratio of dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran is 0.1 mol: 0.205-0.21 mol: 30-45 mg: 50-60 mL. Under the catalysis of trimethylaluminum, diallylamine and dimethyl 3,3'-dithiodipropionate undergo amine ester exchange. The specific reaction route can be expressed as follows:

[0011] Step A2: The intermediate, thioglycolic acid, dimethylphenylphosphine and toluene were mixed, nitrogen was introduced for protection, the temperature was raised to 45-55°C, and stirring was applied at 90-120 rpm and 150-200 W / m 2 UV irradiation, reaction for 3-4 hours, after the reaction is completed, toluene is removed by vacuum rotary evaporation to obtain a modified monomer;

[0012] Furthermore, the usage ratio of the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene is 0.1 mol: 0.4 mol: 20-30 mg: 120-150 mL. Under the catalysis of dimethylphenylphosphine and initiation of ultraviolet radiation, thioglycolic acid and the double bond in the intermediate undergo click addition. The specific reaction route can be expressed as follows:

[0013] Step A3: dissolving adipic acid and a modified monomer in ethanol to obtain a mixed solution a, dissolving hexamethylenediamine in ethanol to obtain a mixed solution b, heating the mixed solution a to 55-65° C., stirring at 40-60 rpm, slowly adding the mixed solution b, reacting for 1.2-1.6 hours, then filtering, washing with water, and drying, adding deionized water to the dried product to redissolve it into a saturated solution, transferring it into a polymerization reactor, introducing nitrogen protection, heating to 220-240° C. to react for 1.6-2 hours, then reducing the pressure to 1 kPa, continuing to heat to 260° C. to continue reacting for 1 hour, discharging, cooling, and slicing to obtain a modified nylon resin;

[0014] Furthermore, the molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.03-0.045:1.15-1.22, and the modified monomer and adipic acid are copolymerized with hexamethylenediamine.

[0015] Preferably, the toughening agent is maleic anhydride grafted POE resin.

[0016] Preferably, the antioxidant is a compound of antioxidant 1098 and antioxidant 626.

[0017] Preferably, the lubricant is polyethylene glycol stearate.

[0018] A preparation method of a renewable marine plastic material PA66, which specifically comprises the following steps: uniformly mixing a modified nylon resin, zinc powder, a toughening agent, an antioxidant and a lubricant, transferring the mixture into a mixing kettle, mixing the mixture at 260±5°C until the torque is stable, discharging the mixture and pelletizing the mixture to obtain the renewable marine plastic material PA66.

[0019] Beneficial effects of the present invention:

[0020] The invention is based on nylon 66 material and discloses a modified nylon resin which can be thermally regenerated at a relatively low temperature. The modified nylon resin is prepared by amine ester exchange between diallylamine and dimethyl 3,3'-dithiodipropionate to prepare an intermediate, and then a modified monomer is prepared by click addition between thioglycolic acid and a double bond in the intermediate, and then the modified monomer is copolymerized with adipic acid and hexamethylenediamine. The modified monomer introduces a disulfide bond with low bond energy into a polymer chain, which is easy to break and melt under high-temperature heat recovery, and the disulfide bond is reformed during the solidification and regeneration process. The blended and compounded zinc powder can promote the breaking of the disulfide bond, and the sulfur-nitrogen structure in the modified monomer forms a chelating effect, which captures zinc powder particles during the blending process, and effectively promotes the breaking of the disulfide bond in situ, effectively reduces the melting point of nylon 66, and realizes the low-energy regeneration of the nylon 66 material. Multi-branched carboxyl groups are introduced into the modified monomer, and micro-crosslinking is formed during the copolymerization process to compensate for the strength reduction problem caused by the modified monomer breaking the regularity of the polymer chain, so that the material maintains good strength and toughness. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Example 1, preparation of renewable marine plastic material PA66, the specific implementation process is as follows:

[0023] (1) Preparation of modified nylon resin

[0024] Step A1: Take dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran, mix them, introduce nitrogen protection, heat to 70°C, stir at 180rpm, and reflux for 2.5h, wherein the amount ratio of dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran is 0.1mol:0.21mol:30mg:60mL. After the reaction, remove tetrahydrofuran by rotary evaporation, wash with water, and vacuum dry to obtain an intermediate.

[0025] Step A2: Take the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene, mix them, introduce nitrogen protection, heat to 55°C, apply 120 rpm stirring and 200 W / m 2 The reaction was carried out under ultraviolet irradiation for 3 hours, wherein the usage ratio of the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene was 0.1 mol: 0.4 mol: 20 mg: 150 mL. After the reaction was completed, toluene was removed by vacuum rotary evaporation to obtain a modified monomer.

[0026] Step A3: add adipic acid and modified monomer to ethanol and stir until completely dissolved, recorded as mixed solution a; add hexamethylenediamine to ethanol and stir until completely dissolved, recorded as mixed solution b; heat the mixed solution a to 65°C, stir at 60rpm, slowly add the mixed solution b, control the addition time to be 30min, continue to stir and react at constant temperature after complete addition, and control the total reaction time of the mixed solution b to be 1.2h, wherein the molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.045:1.22; then filter, wash with water, and dry; add deionized water to the dried product and dissolve it into a saturated solution; transfer it into a polymerization kettle, introduce nitrogen protection, heat it to 240°C and react for 1.6h, then reduce the pressure to 1kPa, continue to heat it to 260°C and continue to react for 1h, discharge it, cool it, and slice it to obtain a modified nylon resin.

[0027] (2) Preparation of renewable marine plastic material PA66

[0028] Ingredients: The raw materials are taken according to weight parts, 100 parts of modified nylon resin, which is homemade in this embodiment; 2.4 parts of zinc powder, with a fineness of 1500 mesh; 11 parts of toughening agent, maleic anhydride grafted POE resin is used in the implementation process, and the KT-913 raw material is selected from Shenyang Ketong Plastic; 0.1 parts of antioxidant, antioxidant 1098 and antioxidant 626 are used in a compounding process according to a weight ratio of 1:1; 1.5 parts of lubricant, polyethylene glycol stearate PEG-7 is used in the implementation process.

[0029] Blending: Add modified nylon resin, zinc powder, toughening agent, antioxidant and lubricant according to weight parts into a high-speed mixer and mix well, transfer to a mixing kettle, mix at 260±5°C until the torque is stable, discharging and pelletizing to obtain renewable marine plastic material PA66.

[0030] Example 2, preparation of renewable marine plastic material PA66, the specific implementation process is as follows:

[0031] (1) Preparation of modified nylon resin

[0032] Step A1: Take dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran, mix them, introduce nitrogen protection, heat to 60°C, stir at 120rpm, and reflux for 3.5h, wherein the amount ratio of dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran is 0.1mol:0.205mol:45mg:50mL. After the reaction, remove tetrahydrofuran by rotary evaporation, wash with water, and vacuum dry to obtain an intermediate.

[0033] Step A2: Take the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene, mix them, introduce nitrogen protection, heat to 45°C, apply 90 rpm stirring and 150 W / m 2 The reaction was carried out under ultraviolet irradiation for 4 hours, wherein the usage ratio of the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene was 0.1 mol: 0.4 mol: 30 mg: 120 mL. After the reaction was completed, toluene was removed by vacuum rotary evaporation to obtain a modified monomer.

[0034] Step A3: add adipic acid and modified monomer to ethanol and stir until completely dissolved, recorded as mixed solution a; add hexamethylenediamine to ethanol and stir until completely dissolved, recorded as mixed solution b; heat the mixed solution a to 55°C, stir at 40rpm, slowly add the mixed solution b, control the addition time to be 50min, continue to stir and react at constant temperature after complete addition, and control the total reaction time of the mixed solution b to be 1.6h, wherein the molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.03:1.15; then filter, wash with water, and dry; add deionized water to dissolve the dried product into a saturated solution, transfer it into a polymerization kettle, introduce nitrogen protection, heat to 220°C for reaction for 2h, then reduce the pressure to 1kPa, continue to heat to 260°C for reaction for 1h, discharge the material, cool and slice it, and obtain a modified nylon resin.

[0035] (2) Preparation of renewable marine plastic material PA66

[0036] Ingredients: The raw materials are taken according to weight parts, 100 parts of modified nylon resin, which is homemade in this embodiment; 1.8 parts of zinc powder, with a fineness of 1500 mesh; 8 parts of toughening agent, maleic anhydride grafted POE resin is used in the implementation process, selected from KT-913 raw material of Shenyang Ketong Plastic; 0.08 parts of antioxidant, antioxidant 1098 and antioxidant 626 are used in a compounding process according to a weight ratio of 1:1; 1.2 parts of lubricant, polyethylene glycol stearate PEG-7 is used in the implementation process.

[0037] Blending: Add modified nylon resin, zinc powder, toughening agent, antioxidant and lubricant according to weight parts into a high-speed mixer and mix well, transfer to a mixing kettle, mix at 260±5°C until the torque is stable, discharging and pelletizing to obtain renewable marine plastic material PA66.

[0038] Example 3, preparation of renewable marine plastic material PA66, the specific implementation process is as follows:

[0039] (1) Preparation of modified nylon resin

[0040] Step A1: Take dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran, mix them, introduce nitrogen protection, heat to 65°C, stir at 120rpm, and reflux for 3h, wherein the amount ratio of dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran is 0.1mol:0.207mol:40mg:60mL. After the reaction, remove tetrahydrofuran by rotary evaporation, wash with water, and vacuum dry to obtain an intermediate.

[0041] Step A2: Take the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene, mix them, introduce nitrogen protection, heat to 50°C, apply 120 rpm stirring and 180 W / m 2 The reaction was carried out under ultraviolet irradiation for 3.2 hours, wherein the usage ratio of the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene was 0.1 mol: 0.4 mol: 25 mg: 140 mL. After the reaction was completed, toluene was removed by vacuum rotary evaporation to obtain a modified monomer.

[0042] Step A3: add adipic acid and modified monomer to ethanol and stir until completely dissolved, recorded as mixed solution a; add hexamethylenediamine to ethanol and stir until completely dissolved, recorded as mixed solution b; heat the mixed solution a to 60°C, stir at 60rpm, slowly add the mixed solution b, control the adding time to be 40min, continue to stir and react at constant temperature after complete addition, and control the total reaction time of the mixed solution b to be 1.4h, wherein the molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.035:1.17; then filter, wash with water, and dry; add deionized water to the dried product and dissolve it into a saturated solution; transfer it into a polymerization kettle, introduce nitrogen protection, heat it to 230°C and react for 1.8h, then reduce the pressure to 1kPa, continue to heat it to 260°C and continue to react for 1h, discharge it, cool it, and slice it to obtain a modified nylon resin.

[0043] (2) Preparation of renewable marine plastic material PA66

[0044] Ingredients: The raw materials are taken according to weight parts, 100 parts of modified nylon resin, which is homemade in this embodiment; 2 parts of zinc powder, with a fineness of 1500 mesh; 10 parts of toughening agent, maleic anhydride grafted POE resin is used in the implementation process, selected from KT-913 raw material of Shenyang Ketong Plastic; 0.09 parts of antioxidant, antioxidant 1098 and antioxidant 626 are used in a compounding process with a weight ratio of 1:1; 1.3 parts of lubricant, polyethylene glycol stearate PEG-7 is used in the implementation process.

[0045] Blending: Add modified nylon resin, zinc powder, toughening agent, antioxidant and lubricant according to weight parts into a high-speed mixer and mix well, transfer to a mixing kettle, mix at 260±5°C until the torque is stable, discharging and pelletizing to obtain renewable marine plastic material PA66.

[0046] Example 4, preparation of renewable marine plastic material PA66, the specific implementation process is as follows:

[0047] (1) Preparation of modified nylon resin

[0048] Step A1: Take dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran, mix them, introduce nitrogen protection, heat to 68°C, stir at 180rpm, and reflux for 2.8h, wherein the amount ratio of dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran is 0.1mol:0.208mol:42mg:60mL. After the reaction, remove tetrahydrofuran by rotary evaporation, wash with water, and vacuum dry to obtain an intermediate.

[0049] Step A2: Take the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene, mix them, pass nitrogen protection, heat to 50°C, apply 120 rpm stirring and 150 W / m 2 The reaction was carried out under ultraviolet irradiation for 3.6 hours, wherein the usage ratio of the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene was 0.1 mol: 0.4 mol: 30 mg: 140 mL. After the reaction was completed, toluene was removed by vacuum rotary evaporation to obtain a modified monomer.

[0050] Step A3: add adipic acid and modified monomer to ethanol and stir until completely dissolved, recorded as mixed solution a; add hexamethylenediamine to ethanol and stir until completely dissolved, recorded as mixed solution b; heat the mixed solution a to 65°C, stir at 60rpm, slowly add the mixed solution b, control the addition time to be 35min, continue to stir and react at constant temperature after complete addition, and control the total reaction time of the mixed solution b to be 1.5h, wherein the molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.04:1.18; then filter, wash with water, and dry; add deionized water to dissolve the dried product into a saturated solution, transfer it into a polymerization kettle, introduce nitrogen protection, heat to 230°C for reaction for 1.8h, then reduce the pressure to 1kPa, continue to heat to 260°C for reaction for 1h, discharge the material, cool and slice it to obtain a modified nylon resin.

[0051] (2) Preparation of renewable marine plastic material PA66

[0052] Ingredients: The raw materials are taken according to weight parts, 100 parts of modified nylon resin, which is homemade in this embodiment; 2.2 parts of zinc powder, with a fineness of 1500 mesh; 10 parts of toughening agent, maleic anhydride grafted POE resin is used in the implementation process, selected from KT-913 type raw material of Shenyang Ketong Plastic; 0.09 parts of antioxidant, antioxidant 1098 and antioxidant 626 are used in a compounding process according to a weight ratio of 1:1; 1.4 parts of lubricant, polyethylene glycol stearate PEG-7 is used in the implementation process.

[0053] Blending: Add modified nylon resin, zinc powder, toughening agent, antioxidant and lubricant according to weight parts into a high-speed mixer and mix well, transfer to a mixing kettle, mix at 260±5°C until the torque is stable, discharging and pelletizing to obtain renewable marine plastic material PA66.

[0054] Comparative Example 1

[0055] This comparative example refers to Example 4. In the preparation process of the modified nylon resin, no modifying monomer is added, the molar ratio of adipic acid to hexamethylenediamine is 1:1.11, and the rest of the implementation process is exactly the same as Example 4.

[0056] Comparative Example 2

[0057] This comparative example refers to Example 4, and in the preparation process of the modified nylon resin, the modified monomer is replaced with 3,3'-dithiodipropionic acid, wherein the molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.08:1.18, and the rest of the implementation process is exactly the same as Example 4.

[0058] The renewable marine plastic material PA66 prepared as above was injection molded into a sample bar, the injection molding temperature was 280°C, and the mechanical properties of the sample bar were tested using a universal material testing machine, and the tensile rate was 20mm / min; the sample bar was subjected to a DSC test using a differential scanning calorimeter, and the temperature change rate was 10°C / min; the specific test data are shown in the following table: Tensile strength / MPa Elongation at break / % Melting temperature / ℃ Example 1 63.29 5.14 240.6 Example 2 66.02 3.35 246.3 Example 3 64.73 3.92 244.5 Example 4 65.08 4.51 241.7 Comparative Example 1 66.17 2.26 263.5 Comparative Example 2 51.39 10.82 255.2

[0059] It can be seen from the test results in the above table that the sample strips of the embodiment maintain good mechanical properties, and the melting temperature is significantly reduced, which is conducive to low-energy melting regeneration of the material.

[0060] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A renewable marine plastic material PA66, characterized in that: In parts by weight: 100 parts of modified nylon resin, 1.8-2.4 parts of zinc powder, 8-11 parts of toughening agent, 0.08-0.1 parts of antioxidant and 1.2-1.5 parts of lubricant; The modified nylon resin is prepared by the following method: Step A1: dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran are mixed, nitrogen is introduced for protection, the temperature is raised to 60-70°C, stirred and refluxed for reaction for 2.5-3.5h, and after the reaction is completed, tetrahydrofuran is removed by rotary evaporation, and then washed with water and dried in vacuo to obtain an intermediate; Step A2: The intermediate, thioglycolic acid, dimethylphenylphosphine and toluene were mixed, nitrogen was introduced for protection, the temperature was raised to 45-55°C, stirred and 150-200W / m 2 UV irradiation, reaction for 3-4 hours, after the reaction is completed, toluene is removed by vacuum rotary evaporation to obtain a modified monomer; Step A3: dissolving adipic acid and a modified monomer in ethanol to obtain a mixed solution a, dissolving hexamethylenediamine in ethanol to obtain a mixed solution b, heating the mixed solution a to 55-65°C, stirring and slowly adding the mixed solution b, reacting for 1.2-1.6h, then filtering, washing with water, and drying, adding deionized water to the dried product to redissolve it into a saturated solution, transferring it into a polymerization kettle, introducing nitrogen protection, heating to 220-240°C to react for 1.6-2h, then reducing the pressure to 1kPa, continuing to heat to 260°C and continuing to react for 1h, discharging, cooling and slicing, and obtaining a modified nylon resin.

2. The renewable marine plastic material PA66 according to claim 1, characterized in that: The usage ratio of dimethyl 3,3'-dithiodipropionate, diallylamine, trimethylaluminum and anhydrous tetrahydrofuran is 0.1 mol: 0.205-0.21 mol: 30-45 mg: 50-60 mL.

3. The renewable marine plastic material PA66 according to claim 2, characterized in that: The usage ratio of the intermediate, thioglycolic acid, dimethylphenylphosphine and toluene is 0.1 mol: 0.4 mol: 20-30 mg: 120-150 mL.

4. The renewable marine plastic material PA66 according to claim 3, characterized in that: The molar ratio of adipic acid, modified monomer and hexamethylenediamine is 1:0.03-0.045:1.15-1.

22.

5. The renewable marine plastic material PA66 according to claim 1, characterized in that: The toughening agent is maleic anhydride grafted POE resin.

6. The renewable marine plastic material PA66 according to claim 1, characterized in that: The antioxidant is compounded by antioxidant 1098 and antioxidant 626.

7. The renewable marine plastic material PA66 according to claim 1, characterized in that: The lubricant is polyethylene glycol stearate.

8. A method for preparing a renewable marine plastic material PA66 according to any one of claims 1 to 7, characterized in that: The specific operation is: mix the modified nylon resin, zinc powder, toughening agent, antioxidant and lubricant, transfer them into a mixing kettle, mix them at 260±5℃ until the torque is stable, discharge and pelletize to obtain renewable marine plastic material PA66.

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