High-strength regenerated PP / PA blending alloy and preparation method thereof

Abstract

The invention belongs to the technical field of plastic blending alloys, and particularly relates to a high-strength regenerated PP / PA blending alloy and a preparation method thereof.The blending alloy is prepared from 60-90 parts of regenerated PP particles, 10-40 parts of regenerated PA6 particles, 1-10 parts of a regenerated PA6 alcoholysis mixture and 0.01-1 part of dicumyl peroxide. According to the PP / PA blending alloy, a commercial compatilizer does not need to be added, and therefore the high-strength regenerated PP / PA blending alloy is obtained. The compatilizer can be formed through in-situ reaction in the melt extrusion process, the compatibility of PP and PA is improved, and the comprehensive performance of the alloy is improved.

Description

Technical Field

[0001] This invention belongs to the field of plastic co-alloy technology, and particularly relates to a high-strength recycled PP / PA co-alloy and its preparation method. Background Technology

[0002] Polypropylene (PP) is one of the five major general-purpose plastics (PE, PP, PS, PVC, ABS). Due to its good chemical stability, mechanical properties, low density, and low price, it has become the world's second-largest general-purpose synthetic resin, widely used in various industries. However, PP also has drawbacks such as low tensile strength and insufficient thermal stability, limiting its further widespread application. Nylon (PA) is an engineering plastic with good thermal stability and mechanical properties, widely used in the automotive, electronics, and home appliance industries. However, PA has the disadvantage of high water absorption, and its price is higher than PP, further limiting its applications. By melt blending to prepare PP / PA alloys, the advantages of both materials can be combined to obtain alloy products with good mechanical properties, thermal stability, and low water absorption, greatly expanding the product's applications.

[0003] However, due to the significant polarity difference between PP and PA, they are thermodynamically incompatible systems, and simple mechanical blending will result in a "sea-island" structure. When PP is used as the matrix and a small amount of PA is added, the more polar PA6 will act as an "island phase" dispersed in the continuous PP phase. Because the interfacial tension between PP and PA is high and the interfacial interaction is weak, the mechanical properties of alloy systems prepared by direct blending are poor. Existing technologies often use compatibilizers to reduce the interfacial tension between PP and PA, thereby improving the alloy's performance. For example, CN114591622A discloses a polyamide-polypropylene alloy material and its preparation method and application. The material of this invention includes the following components by weight: 20-55 parts polyamide 6 resin, 18-30 parts polypropylene resin, 4-10 parts PA MXD6 resin, 3-8 parts ethylene-vinyl alcohol copolymer, 3-8 parts compatibilizer, 25-35 parts glass fiber, 0.5-1 part antioxidant, and 0.5-1 part lubricant. This invention uses maleic anhydride-grafted polypropylene, PA MXD6 resin, and EVOH to compatibilize and modify PA6 and PP resins, significantly improving their heat aging resistance, electrolyte resistance, tensile strength, and product appearance. However, this invention still faces the challenge of further optimizing the compatibilizer formulation and ratio to enhance the compatibility between polyamide 6 resin and polypropylene resin. Summary of the Invention

[0004] The purpose of this invention is to provide a PP / PA blend with good mechanical properties and its preparation method, which can achieve good mechanical properties without adding traditional compatibilizers such as maleic anhydride-grafted polypropylene (PP-MAH) to the PP / PA blend.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-strength recycled PP / PA blend gold is made from the following raw materials: 60-90 parts recycled PP particles, 10-40 parts recycled PA6 particles, 1-10 parts recycled PA6 alcoholysis mixture, and 0.01-1 parts dicumyl peroxide.

[0006] Furthermore, it is made from the following raw materials: 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 1 to 10 parts of recycled PA6 alcoholysis mixture, and 0.05 to 0.3 parts of dicumyl peroxide.

[0007] Furthermore, the recycled PP particles are post-consumer recycled, obtained through sorting, crushing, washing, drying, and melt granulation; their recycling sources are one or more combinations of lunch boxes, fruit baskets, pipes, and boards.

[0008] Furthermore, the recycled PA6 particles are post-consumer recycled, obtained through sorting, crushing, washing, drying, and melt granulation; their recycling sources are one or more combinations of waste fishing net wire, industrial waste wire, and cast nylon.

[0009] Furthermore, the recycled PA6 alcoholysis mixture is obtained from post-consumer recycled fishing net nylon after sorting, crushing, washing, drying, and methanol alcoholysis.

[0010] Furthermore, the preparation method of the regenerated PA6 alcoholysis mixture is as follows: S1. First, the recycled fishing net nylon is sorted, crushed, washed, and dried to obtain processed fishing net nylon scrap. S2. Take 90-110 parts of broken fishing net wire, 550-650 parts of methanol, and 1.5-2.5 parts of alcoholysis catalyst and add them to a high-pressure reactor. Under a nitrogen atmosphere, heat the mixture to 150-240℃ and stir for 0.5-5 hours. Then, place the reactor in cold water to cool it down to room temperature. After the reaction is complete, take out the paste-like semi-solid and place it in a forced-air drying oven to remove the methanol.

[0011] Furthermore, the alcoholysis catalyst is at least one of a solid acid (phosphotungstic acid, p-toluenesulfonic acid) or a base (sodium hydroxide, potassium hydroxide).

[0012] Furthermore, the reaction temperature in step S2 is 160~240℃, and the stirring reaction time is 0.5~2 hours.

[0013] Another object of the present invention is to provide a method for preparing a high-strength recycled PP / PA co-blended gold, comprising the following steps: (1) Weigh out the recycled PP particles, recycled PA6 particles, recycled PA6 alcoholysis mixture and dicumyl peroxide by weight and then dry mix them in a high-speed mixer for 3-5 minutes. (2) Feed the mixed raw materials into a twin-screw extruder, control the motor frequency at 30~40Hz, and set the temperature of each zone between 180~240℃. The mixture is then melt-extruded and granulated.

[0014] Furthermore, the twin-screw extruder has 11 temperature control zones: temperature control zone 1 is 180~185℃, temperature control zone 2 is 205~210℃, temperature control zones 3~4 are 215~220℃, temperature control zone 5 is 225~230℃, temperature control zones 6~9 are 220~225℃, temperature control zone 10 is 215~220℃, and temperature control zone 11 is 205~210℃.

[0015] Mechanism: This invention uses methanol as the reaction medium to degrade PA, and the resulting PA alcoholysis depolymer is a mixture of methyl adipate and methyl 5-hexenoate. At high temperature, DCP peroxide is used to generate free radicals in the PP molecular chain. The generated free radicals further react with the double bonds of methyl 5-hexenoate in the PA alcoholysis depolymer to form PP / PA graft copolymer. This copolymer can be used as a compatibilizer for PP / PA alloys, improving the compatibility of PP / PA alloys and improving the mechanical properties of the materials.

[0016] The advantages of this invention are: 1. The PP and PA used in this invention are both post-consumer recycled plastics, and the products can be recycled and reused, which can avoid secondary harm to the environment; 2. The PP / PA blend alloy provided by this invention does not require the addition of commercially available compatibilizers. Instead, it can form compatibilizers in situ during melt extrusion, thereby improving the compatibility of PP and PA and enhancing the overall performance of the alloy. 3. The PP / PA copolymer provided by this invention has good mechanical properties, with a tensile strength of not less than 30 MPa and an impact strength of not less than 5 kJ / m. 2 The bending strength is not less than 40MPa and the bending modulus is not less than 1200MPa. Detailed Implementation

[0017] In the composite material formulations of the examples and comparative examples: the recycled PP particles are prepared from recycled eyeglass cases; the recycled PA6 particles are prepared from used fishing net wire; the recycled PA6 alcoholysis mixture is prepared by alcoholysis of used fishing net wire under certain process conditions; dicumyl peroxide (DCP) is a commercially available product that can be purchased from Nanjing Chemical Reagent Co., Ltd., Jiangsu Daoming Chemical Co., Ltd., or Weifang Shandao Chemical Co., Ltd., etc. Example 1

[0018] First, a mixture of regenerated PA6 alcoholysis was prepared. The steps are as follows: S1-1: First, the recycled fishing net nylon after consumption is sorted, crushed, washed and dried to obtain processed fishing net nylon crushed material; S1-2: Take 100 parts of fishnet wire scrap, 600 parts of methanol, and 2 parts of phosphotungstic acid and add them to a high-pressure reactor. Replace the air inside the reactor with nitrogen, then heat to 240℃ and stir for 2 hours. After the reaction is complete, place the reactor in cold water to cool it down to room temperature quickly.

[0019] S1-3: After the reaction is complete, the paste-like semi-solid obtained is taken out of the reaction vessel and placed in a forced-air drying oven to dry and remove methanol, thus obtaining the final product; Then, the various components are mixed evenly and granulated. The specific process is as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 1 part of recycled PA6 alcoholysis mixture, and 0.10 parts of dicumyl peroxide according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 4 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 35Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃. Example 2

[0020] First, a mixture of regenerated PA6 alcoholysis was prepared. The steps are as follows: S1-1: First, the recycled fishing net nylon after consumption is sorted, crushed, washed and dried to obtain processed fishing net nylon crushed material; S1-2: Take 100 parts of fishnet wire scrap, 600 parts of methanol, and 2 parts of p-toluenesulfonic acid and add them to a high-pressure reactor. Replace the air inside the reactor with nitrogen, then heat to 240℃ and stir for 1 hour. After the reaction is complete, place the reactor in cold water to cool it down to room temperature quickly.

[0021] S1-3: After the reaction is complete, the paste-like semi-solid obtained is taken out of the reaction vessel and placed in a forced-air drying oven to dry and remove methanol, thus obtaining the final product; Then, the various components are mixed evenly and granulated. The specific process is as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 3 parts of recycled PA6 alcoholysis mixture, and 0.10 parts of dicumyl peroxide according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 4 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 30~40Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃. Example 3

[0022] First, a mixture of regenerated PA6 alcoholysis was prepared. The steps are as follows: S1-1: First, the recycled fishing net nylon after consumption is sorted, crushed, washed and dried to obtain processed fishing net nylon crushed material; S1-2: Take 100 parts of fishnet wire scrap, 600 parts of methanol, and 2 parts of sodium hydroxide and add them to a high-pressure reactor. Replace the air inside the reactor with nitrogen, then heat to 240℃ and stir for 1 hour. After the reaction is complete, place the reactor in cold water to cool it down to room temperature quickly.

[0023] S1-3: After the reaction is complete, the paste-like semi-solid obtained is taken out of the reaction vessel and placed in a forced-air drying oven to dry and remove methanol, thus obtaining the final product; Then, the various components are mixed evenly and granulated. The specific process is as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 5 parts of recycled PA6 alcoholysis mixture, and 0.05 parts of dicumyl peroxide according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 3 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 40Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃. Example 4

[0024] First, a mixture of regenerated PA6 alcoholysis was prepared. The steps are as follows: S1-1: First, the recycled fishing net nylon after consumption is sorted, crushed, washed and dried to obtain processed fishing net nylon crushed material; S1-2: Take 100 parts of fishnet wire scrap, 600 parts of methanol, and 2 parts of potassium hydroxide and add them to a high-pressure reactor. Replace the air inside the reactor with nitrogen, then heat to 240℃ and stir for 1 hour. After the reaction is complete, place the reactor in cold water to cool it down to room temperature quickly.

[0025] S1-3: After the reaction is complete, the paste-like semi-solid obtained is taken out of the reaction vessel and placed in a forced-air drying oven to dry and remove methanol, thus obtaining the final product; Then, the various components are mixed evenly and granulated. The specific process is as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 10 parts of recycled PA6 alcoholysis mixture, and 0.30 parts of dicumyl peroxide according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 5 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 30Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃.

[0026] Comparative Example 1 This comparative example does not include the recycled PA6 alcoholysis mixture. All components are mixed thoroughly and then granulated, as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, and 0.10 parts of dicumyl peroxide according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 4 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 35Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃.

[0027] Comparative Example 2 First, a mixture of regenerated PA6 alcoholysis was prepared. The steps are as follows: S1-1: First, the recycled fishing net nylon after consumption is sorted, crushed, washed and dried to obtain processed fishing net nylon crushed material; S1-2: Take 100 parts of fishnet wire scrap, 600 parts of methanol, and 2 parts of phosphotungstic acid and add them to a high-pressure reactor. Replace the air inside the reactor with nitrogen, then heat to 240℃ and stir for 1 hour. After the reaction is complete, place the reactor in cold water to cool it down to room temperature quickly.

[0028] S1-3: After the reaction is complete, the paste-like semi-solid obtained is taken out of the reaction vessel and placed in a forced-air drying oven to dry and remove methanol, thus obtaining the final product; Then, the various components are mixed evenly and granulated. The specific process is as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, and 5 parts of recycled PA6 alcoholysis mixture according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 4 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 35Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃.

[0029] Comparative Example 3 First, a mixture of regenerated PA6 alcoholysis was prepared. The steps are as follows: S1-1: First, the recycled fishing net nylon after consumption is sorted, crushed, washed and dried to obtain processed fishing net nylon crushed material; S1-2: Take 100 parts of fishnet wire scrap, 600 parts of methanol, and 2 parts of p-toluenesulfonic acid and add them to a high-pressure reactor. Replace the air inside the reactor with nitrogen, then heat to 160℃ and stir for 0.5 hours. After the reaction is complete, place the reactor in cold water to cool it down to room temperature quickly.

[0030] S1-3: After the reaction is complete, the paste-like semi-solid obtained is taken out of the reaction vessel and placed in a forced-air drying oven to dry and remove methanol, thus obtaining the final product; Then, the various components are mixed evenly and granulated. The specific process is as follows: S2-1 Weigh out 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 5 parts of recycled PA6 alcoholysis mixture, and 0.10 parts of dicumyl peroxide according to the required weight; S2-2 Dry mix the raw materials in a high-speed mixer for 4 minutes; S2-3 The mixed raw materials are fed into the twin-screw extruder through the feed port. The frequency of the feeder motor is controlled at 35Hz, and the temperature of each zone is set between 180~240℃. The product is obtained by melt extrusion granulation. The twin-screw extruder has 11 temperature control zones: zone 1 has a temperature of 180℃, zone 2 has a temperature of 210℃, zones 3-4 have a temperature of 220℃, zone 5 has a temperature of 230℃, zones 6-9 have a temperature of 225℃, zone 10 has a temperature of 220℃, and zone 11 has a temperature of 210℃.

[0031] Performance testing The physical properties of the product of this invention are characterized according to GB standards, including melt flow index, IZOD notched impact strength, tensile strength, flexural strength, and flexural modulus.

[0032] The material property test results for the comparative and implementation cases are as follows: The impact strength of Examples 1-5 is all above 5 kJ / m. 2 The above-mentioned tensile strength (above 30 MPa), flexural strength (above 40 MPa), and flexural modulus (above 1200 MPa) demonstrate good mechanical properties. Specific results are shown in Table 1. Table 1 Comparison of physical properties of comparative examples and embodiments Physical properties IZOD notched impact strength 23℃ Tensile strength Bending strength Flexural modulus unit <![CDATA[KJ / m 2 ]]> MPa MPa MPa Example 1 5.8 31 38 1487 Example 2 6.8 34 41 1562 Example 3 7.5 37 45 1763 Example 4 5.8 32 43 1486 Comparative Example 1 3.5 27 32 1263 Comparative Example 2 3.1 28 33 1293 Comparative Example 3 4.6 30 35 1387 The data in the table shows that the overall performance of the PP / PA6 alloy initially increases and then decreases with increasing PA6 alcoholysis product content. The alloy exhibits optimal overall performance when the PA6 alcoholysis product content is 5 parts. Excessive alcoholysis product content can actually lead to a decrease in mechanical properties. This is because a higher alcoholysis product content results in more terminal amino and carboxyl group byproducts in the PA6 alcoholysis product. These byproducts cannot react with PP and remain as small molecule impurities in the PP / PA6 alloy, thus adversely affecting its mechanical properties.

[0033] Comparative Examples 1 and 2 show that if only DCP is added without adding PA6 alcoholysis product, DCP will break the PP molecular chains, reduce the molecular weight, and lead to a decrease in the mechanical properties of the PP / PA alloy. When only PA6 alcoholysis product is added without adding DCP, the PA alcoholysis product cannot be connected with PP, and therefore cannot act as a compatibilizer to improve the interfacial bonding force of the PP / PA alloy, resulting in a significant decrease in the mechanical properties of the alloy.

[0034] Comparative Example 3 shows that the alcoholysis conditions of the alcoholysis product also affect its compatibilizing effect. If the alcoholysis reaction time is insufficient, the terminal groups of the PA6 alcoholysis product do not have enough double bonds, and therefore cannot synergistically exert a toughening effect with DCP.

[0035] In summary, through a series of explorations, this invention utilizes methanol as a reaction medium to degrade PA, resulting in a PA alcoholysis depolymerization product that is a mixture of methyl adipate and methyl 5-hexenoate. At high temperature, DCP peroxide is used to generate free radicals in the PP molecular chain. These free radicals further react with the double bonds of methyl 5-hexenoate in the PA alcoholysis depolymerization product to form a PP / PA graft copolymer. This copolymer can serve as a compatibilizer for PP / PA alloys, improving their compatibility and enhancing the mechanical properties of the material.

Claims

1. A high-strength recycled PP / PA co-mixture, characterized in that: The following raw materials are used: 60-90 parts of recycled PP particles, 10-40 parts of recycled PA6 particles, 1-10 parts of recycled PA6 alcoholysis mixture, and 0.01-1 part of dicumyl peroxide.

2. The high strength recycled PP / PA co-compound of claim 1, wherein: The following raw materials are used: 70 parts of recycled PP particles, 30 parts of recycled PA6 particles, 1-10 parts of recycled PA6 alcoholysis mixture, and 0.05-0.3 parts of dicumyl peroxide.

3. The high strength recycled PP / PA co-compound of claim 1, wherein: The recycled PP particles are post-consumer recycled, obtained after sorting, crushing, cleaning, drying, and melt granulation; and the recycling source is one or a combination of more than two of meal boxes, fruit baskets, pipe materials, and plate materials.

4. The high strength recycled PP / PA co-compound of claim 1, wherein: The recycled PA6 particles are post-consumer recycled, obtained after sorting, crushing, cleaning, drying, and melt granulation; and the recycling source is one or a combination of more than two of discarded fishing net silk, industrial waste silk, and casting nylon.

5. The high strength recycled PP / PA co-compound of claim 1, wherein: The recycled PA6 alcoholysis mixture is post-consumer recycled fishing net silk nylon, obtained after sorting, crushing, cleaning, drying, and methanol alcoholysis.

6. The high-strength recycled PP / PA co-mixture of claim 5, wherein: The preparation method of the recycled PA6 alcoholysis mixture is as follows: S1. First, the post-consumer recycled fishing net silk nylon is sorted, crushed, cleaned, and dried to obtain treated fishing net silk crushed material; S2. Take 90-110 parts of fishing net silk crushed material, 550-650 parts of methanol, and 1.5-2.5 parts of alcoholysis catalyst, and add them to a high-pressure reaction kettle, heat to 150-240℃ under nitrogen atmosphere, stir for 0.5-5 hours, then quickly cool to room temperature in cold water, take out the obtained paste-like semi-solid, and place it in a forced air drying oven to remove methanol.

7. The high-strength recycled PP / PA co-mixture of claim 6, wherein: The alcoholysis catalyst is at least one of a solid acid or a base.

8. The high strength recycled PP / PA co-compound of claim 6, wherein: The reaction temperature in step S2 is 160-240℃, and the stirring reaction time is 0.5-2 hours.

9. The process for the preparation of high-strength recycled PP / PA co- blends according to any one of claims 1 to 8, characterized in that, The following steps are included: (1) Weigh the recycled PP particles, recycled PA6 particles, recycled PA6 alcoholysis mixture, and dicumyl peroxide by weight, and place them in a high-speed stirrer for dry mixing for 3-5 minutes; (2) Feed the mixed raw materials into a twin-screw extruder, control the motor frequency at 30-40 Hz, and set the temperature of each zone to 180-240℃, then melt extrude and granulate.

10. The production method according to claim 9, characterized by: The twin-screw extruder is provided with 11 temperature control zones, the temperature of temperature control zone 1 is 180-185℃, the temperature of temperature control zone 2 is 205-210℃, the temperature of temperature control zones 3-4 is 215-220℃, the temperature of temperature control zone 5 is 225-230℃, the temperature of temperature control zones 6-9 is 220-225℃, the temperature of temperature control zone 10 is 215-220℃, and the temperature of temperature control zone 11 is 205-210℃.