Self-repairing PVC-U injection molding grade modified material and control method

Abstract

The invention discloses a self-repairing PVC-U injection molding grade modified material and a control method, the self-repairing PVC-U injection molding grade modified material comprises a base material and a self-repairing microcapsule, the base material comprises the following components by mass: 80 parts of PVC resin; 20 parts of PVC with an ultralow polymerization degree; 5 parts of a calcium-zinc stabilizer; 1 part of a lubricant; 2 parts of ACR resin; 10 to 15 parts of nano calcium carbonate; the content of the self-repairing microcapsule is 5 to 10 weight percent. According to the invention, the material with the self-repairing effect can be obtained, so that the subsequently produced product has a certain self-repairing effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, and more particularly to a self-repairing PVC-U injection grade modified material and a method for controlling material extrusion temperature. BACKGROUND

[0002] For the existing PVC pipe, a certain micro-crack is prone to be generated due to mechanical stress, chemical corrosion or improper installation during use, which leads to the problem of easy leakage. The current repair technology usually adopts a manual induction method and depends on manual intervention for repair, including but not limited to using glue, welding, replacing parts and the like to repair the micro-crack part. Some PVC materials have microcapsules with self-repairing mixed in the base material, so that the base material has a certain self-repairing effect. The self-repairing microcapsule usually includes an outer shell and an inner self-repairing material to form a capsule-shaped self-repairing material. When a micro-crack is generated, the self-repairing material in the capsule can achieve the effect of bonding and supplementing the crack, thereby achieving the effect of self-repairing.

[0003] During the production of the self-repairing material, the self-repairing material is usually mixed with other PVC base materials to obtain a self-repairing masterbatch capable of achieving injection molding. The content of the microcapsule in the self-repairing masterbatch is relatively high, and the temperature during extrusion needs to be strictly controlled. When the extrusion temperature is too high, the outer coating shell material is easily damaged, which easily leads to the coagulation of the self-repairing material and affects the dispersibility of the self-repairing material in the subsequent production process. When the base temperature is too low, the normal extrusion and granulation are affected.

[0004] Therefore, a new scheme needs to be proposed to solve this problem. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a self-repairing PVC-U injection grade modified material and a control method.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] A self-repairing PVC-U injection grade modified material, comprising a base material and self-repairing microcapsules, the components of the base material include, by mass fraction:

[0008] PVC resin 80 parts;

[0009] Ultra-low polymerization degree PVC 20 parts;

[0010] Calcium-zinc stabilizer 5 parts;

[0011] Lubricant 1 part;

[0012] ACR resin 2 parts;

[0013] Nano calcium carbonate 10-15 parts;

[0014] The self-repairing microcapsule is 5-10 wt%.

[0015] The application further provides that the preparation steps of the self-repairing PVC-U injection grade modified material include:

[0016] Step A1: mix the PVC resin, the ultra-low polymerization degree PVC, the calcium-zinc stabilizer, the lubricant, the ACR resin, and the nano calcium carbonate according to the proportion;

[0017] Step A2: add the self-repairing microcapsule to the mixture after Step A1, and mix the self-repairing microcapsule;

[0018] Step A3: extrude and granulate the mixture after Step A2 to obtain the self-repairing PVC-U injection grade modified material.

[0019] The application further provides that in Step A1, the temperature during the mixing process is set to 82-88℃; in Step A2, the rotating speed of the mixing and stirring is controlled to 100-150 rpm; and in Step A2, the self-repairing microcapsule in the mixture is 5-10 wt%.

[0020] In Step A3, the modified material is extruded through an extruder, and the extruder is installed with an extrusion die to shape the extruded material into a strip structure.

[0021] The application further provides that the PVC resin is SG-8 type PVC resin; the average polymerization degree of the ultra-low polymerization degree PVC is below 300; and the lubricant is calcium stearate or zinc stearate.

[0022] The application further provides that the preparation steps of the self-repairing microcapsule include:

[0023] Step B1: mix epoxy resin E-51 and dicyandiamide curing agent according to the mass ratio of 10:1, add 0.5% of coupling agent KH-550, and uniformly ultrasonically disperse;

[0024] Step B2: adopt in-situ polymerization to dissolve methyl methacrylate (MMA) monomer, crosslinking agent divinylbenzene (DVB), and initiator AIBN in water phase, react at 60℃ for 6 hours, and form PMMA shell layer to wrap the microcapsule of the core material;

[0025] Step B3: after filtration, washing, and drying, screen the microcapsule with a particle size of 80-120μm for standby use.

[0026] The application also provides a material extrusion temperature control method, which comprises the following steps:

[0027] The control method comprises the following steps:

[0028] Step 1: obtaining the theoretical design temperature T0 of the material at the outlet of the die section and the theoretical design extrusion speed N of the extruder according to the extrusion requirements of the material;

[0029] Step 2: setting the temperature of the die section as T1 and the temperature of the pre-extrusion section as T2, and T1>T2;

[0030] The temperature difference P between T1 and T2 is P=T1-T2;

[0031] Step 3: detecting and recording the actual temperature T3 of the outlet of the die section every interval s during the extrusion process; i represents the detection times, and the actual detection temperature at the ith detection is recorded as T3(i), and the extrusion speed of the current extruder is N(i);

[0032] The initial value of i is 0, and each detection record is recorded as i=i+1;

[0033] Step 4: calculating the difference ΔT(i) between T0 and T3(i), ΔT(i)=T3(i)-T0;

[0034] Step 5: adjusting the extrusion speed of the extruder according to the relationship between ΔT(i) and the threshold range, and the adjusted extrusion speed of the extruder is N(i+1);

[0035] Step 6: the extruder runs at the adjusted extrusion speed N(i+1);

[0036] Circulating steps 3, 4 and 5, if ΔT(i) is in the threshold range for three times in succession, the extruder runs in a stable state.

[0037] In step 5, the material generates a temperature rise during the extrusion in the die section, the temperature rise is inversely proportional to the extrusion speed of the extruder and is proportional to the difference P between the set temperatures T1 and T2, and the temperature rise proportional coefficient is k;

[0038] The correlation of the adjusted extrusion speed N(i+1) of the extruder is:

[0039]

[0040] The present invention is further configured such that α(i) is set as the speed adjustment coefficient of the extruder, and N(i+1)=(1+α(i))·N(i);

[0041]

[0042] The initial value of α(i) is α(0), α(0)=0.

[0043] The present invention is further configured such that, in step 6, when running in a steady state, N(i+1) = (1+σ1)·N(i);

[0044] σ1 is the stability compensation coefficient, σ1=[50%·α(i)+30%·α(i-1)+20%·α(i-2)]·A;

[0045] Set the temperature difference offset coefficient A, A=T3(i) / T2.

[0046] The present invention is further configured such that, in step 6, if ΔT(i) exceeds the threshold range three times consecutively, the system operates in a corrected state.

[0047] When running in the corrected state, N(i+1) = (1 + σ2)·N(i);

[0048] σ2 is the correction coefficient for the corrected state, σ2=[50%·α(i)+30%·α(i-1)+20%·α(i-2)] / A;

[0049] Set the temperature difference offset coefficient A, A=T3(i) / T2.

[0050] In summary, the present invention has the following beneficial effects:

[0051] This solution can maintain stable set temperatures T1 and T2 during operation by adjusting the extrusion speed of the extruder. It only adjusts the extrusion parameters of the extruder, and the adjustment of a single parameter can reduce the impact of fluctuations in other parameters and simplify the parameter adjustment process of the extrusion process. Attached Figure Description

[0052] Figure 1 This is a production flow diagram of a self-healing PVC-U injection molding grade modified material in this embodiment;

[0053] Figure 2 This is a flowchart illustrating the production process of the self-healing microcapsules in this embodiment;

[0054] Figure 3 This is a flowchart of a method for controlling the material extrusion temperature in this embodiment. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] This embodiment discloses a method for controlling the extrusion temperature of materials. The material is extruded through an extruder. The extruder is equipped with an extrusion die, which can form the extruded material into a strip structure. The material is extruded along the extrusion channel. It first passes through the preheating section of the extrusion section to heat the temperature to a stable state, and then passes through the die section for extrusion.

[0058] The heating length in the pre-extrusion section is relatively long, and the material stays in the extrusion process for a longer time, usually more than 20 seconds. This allows the material to be fully heated in the pre-extrusion section, but the temperature is relatively low, lower than the preset extrusion stability. Then, during the extrusion process, the material will pass through the die section for further heating. The temperature in the die section is relatively higher, but the heating length in the die section is short. By heating the material quickly in a short time, the material can be heated to the designed base temperature, while avoiding the adverse effects of excessive heating length, such as coking.

[0059] In this embodiment, the control method includes the following steps:

[0060] Step 1: Based on the extrusion requirements of the material, obtain the theoretical design temperature T0 of the material at the exit of the die section and the theoretical design extrusion speed N of the extruder; T0 and N are both fixed values, which are related to the material to be extruded and are determined according to the properties of the material during product design.

[0061] Among them, the speed N of the extruder is related to the rotational speed of the extruder, which can be determined by parameters such as the cross-section of the extruder. In actual production, it can be correlated with the rotational speed of the extruder. N = n·kp, where n is the rotational speed of the extruder and kp is the ratio coefficient between the rotational speed and the extrusion speed, which is a known parameter of the extruder itself.

[0062] Step 2: Based on the extrusion design requirements of the material, set the temperature of the die section and the front section of the extrusion. The set temperature of the die section is T1, and the set temperature of the front section of the extrusion is T2. T1 and T2 are both pre-designed values ​​of the process, and T1>T2.

[0063] The temperature difference between T1 and T2 is P, where P = T1 - T2;

[0064] Step 3: During the extrusion process, the actual temperature T3 at the exit of the die section is detected and recorded at every time interval s; let i represent the number of detections, and the actual detected temperature during the i-th detection is recorded as T3(i), and the current extrusion speed of the extruder is N(i).

[0065] The initial value of i is 0. Each detection is recorded as i = i + 1. For example, in the first detection, i = 1; in the next detection, i = 1 + 1.

[0066] Step 4: Calculate the difference ΔT(i) between T0 and T3(i), where ΔT(i) = T3(i) - T0;

[0067] Step 5: Adjust the extrusion speed of the extruder according to the relationship between ΔT(i) and the threshold range;

[0068] ΔT(i) represents the difference between the actual temperature and the theoretical design temperature during detection. When the difference does not exceed the threshold range, it indicates that the actual production temperature is relatively small compared with the theoretical design temperature, and the temperature is basically in a stable state, so there is no need for balance adjustment for the time being.

[0069] When the difference exceeds the threshold range, it indicates that the difference between the current actual production temperature and the theoretical design temperature is too large and needs to be balanced. During the adjustment process, if the temperature of T3(i) is greater than the theoretical design temperature T0, it indicates that the current temperature at the die section is too high. This can be achieved by increasing the extrusion speed of the extruder, which will increase the extrusion speed of the material, shorten the time the material spends in the die section, shorten the time the material is heated in the die section, and thus slightly reduce the temperature rise of the material in the die section, so as to achieve temperature balance adjustment of the material.

[0070] During the adjustment process, if the temperature of T3(i) is less than the theoretical design temperature T0, it indicates that the current temperature at the die section is too low. The extrusion speed of the extruder can be reduced to decrease the extrusion speed of the material, prolong the time the material spends in the die section, prolong the time the material is heated in the die section, and thus slightly increase the temperature rise of the material in the die section, so as to achieve temperature balance adjustment of the material.

[0071] Specifically, the extrusion speed of the adjusted extruder is N(i+1), which is the base speed in the next detection cycle.

[0072] The material generates a temperature rise during the extrusion process in the die section. The temperature rise is inversely proportional to the extrusion speed of the extruder and directly proportional to the difference P between the set temperatures T1 and T2.

[0073] The temperature rise proportionality coefficient is set to k. The proportionality coefficient k is an operating parameter determined by the extruder itself and the extruded material.

[0074] In the initial stage of operation, the set temperature of the die section is T1, and the set temperature of the extrusion front section is T2. Based on the temperature difference, the temperature rise ratio coefficient k in this production test is obtained, and the specific relationship is as follows:

[0075]

[0076] Substituting the parameters, we obtain the temperature rise ratio coefficient k in this production test.

[0077] In step 5, the material generates a temperature rise during extrusion in the die section. The temperature rise is inversely proportional to the extrusion speed of the extruder and directly proportional to the difference P between the set temperatures T1 and T2. The temperature rise proportionality coefficient is k.

[0078] The correlation of the adjusted extruder speed N(i+1) is as follows:

[0079]

[0080] Let α(i) be the speed adjustment coefficient of the extruder, and N(i+1) = (1 + α(i))·N(i). Substituting N(i+1) into the above equation, we get the following relationship:

[0081]

[0082] The speed regulation coefficient α(i) is obtained through calculation:

[0083]

[0084] In this embodiment, α(i) is dynamically adjusted according to the number of detections i, and when i=0, the initial value of α(i) is α(0), α(0)=0.

[0085] Step 6: The extruder operates at the adjusted extrusion speed N(i+1), that is, the extruder operates with the adjusted parameters;

[0086] Repeat steps 3, 4, and 5, that is, every time interval s, the actual detected temperature of the next cycle is recorded as T3(i+1) and the operating parameters of the extruder are adjusted according to T3(i+1), and the speed of the extruder is adjusted accordingly.

[0087] During the cyclic detection and correction process, if ΔT(i) is within the threshold range for three consecutive times, it indicates that the extruder's operating state is stable, the current extrusion speed can meet the current extrusion requirements, and the actual temperature obtained at the die section outlet meets the material's design requirements. The extruder then enters a stable state and operates in a stable state.

[0088] In step 6, during steady-state operation, the operating parameters of the extruder are adjusted with a stability compensation coefficient σ1, where σ1 is the stability compensation coefficient; in the next adjustment process, the extrusion speed of the extruder is N(i+1)=(1+σ1)·N(i);

[0089] σ1 is the stability compensation coefficient, adjusted based on the relatively stable states of the previous three tests. According to the adjustment weights, the current detection coefficient α(i) has a weight of 50%, the previous detection coefficient α(i-1) has a weight of 30%, and the previous two detection coefficients α(i-2) have a weight of 20%. This allows us to obtain σ1.

[0090] σ1=[50%·α(i)+30%·α(i-1)+20%·α(i-2)]·A;

[0091] By introducing the proportional coefficients of the previous two times, the amplitude of the next adjustment can be made more balanced in the region during the adjustment process. Since the states on both sides can reach the threshold range of temperature deviation, it indicates that the adjustment coefficients on both sides can meet the adjustment requirements. By combining three detections, the impact of a single fluctuation can be reduced.

[0092] Among them, the temperature difference offset coefficient A is set, A=T3(i) / T2. Since T2 is the set heating temperature and T3(i) is the actual detected temperature, under normal circumstances, the value of T3(i) cannot reach the set temperature T2. T3(i) is generally 90%~95% of T2. The offset coefficient A can reduce the stability compensation coefficient σ1, thereby reducing the adjustment range during stable operation, so that the adjustment range and fluctuation of the extruder can be dynamically stable in the region.

[0093] In step 6, if ΔT(i) exceeds the threshold range three times in a row, it indicates that the extruder is not running stably and the current extrusion parameters cannot meet the current extrusion requirements. At the exit of the die section, it will operate in a correction state and the extruder needs to be adjusted with a larger adjustment range so that the parameters of the extruder can reach the threshold range more quickly.

[0094] During the operation in the correction state, the operating parameters of the extruder are adjusted by the correction state correction coefficient σ2, where σ2 is the correction state correction coefficient; in the next adjustment process, the extrusion speed of the extruder is N(i+1)=(1+σ2)·N(i);

[0095] σ2 is the correction coefficient for the correction state. When running in the correction state, N(i+1)=(1+σ2)·N(i);

[0096] Adjustments are made based on the states of the previous three tests. Based on the weights of the adjustments, the weight of the current detection coefficient α(i) is 100%, the weight of the previous detection coefficient α(i-1) is 30%, and the weight of the previous two detection coefficients α(i-2) is 20%. This yields σ2, where σ2 = [α(i) + 30%·α(i-1) + 20%·α(i-2)] / A.

[0097] By introducing the proportional coefficients of the previous two adjustments, the adjustment range of the next adjustment can be larger during the adjustment process, allowing for faster adjustment of the extruder parameters. This enables the extruder to reach a stable state in fewer adjustments. The adjustment range of σ2 is approximately 1.5 times the normal adjustment range α(i), thus appropriately increasing the adjustment range while avoiding over-adjustment due to excessively large single adjustment ranges.

[0098] Among them, the temperature difference offset coefficient A is set, A=T3(i) / T2. Since T2 is the set heating temperature and T3(i) is the actual detected temperature, under normal circumstances, the value of T3(i) cannot reach the set temperature T2. T3(i) is generally 90%~95% of T2. The offset coefficient A can also be used to compensate for the coefficient σ, thereby improving the adjustment efficiency.

[0099] Then, by repeating the above steps, the actual temperature T3(i) in each detection cycle is repeatedly detected, and the extruder is dynamically adjusted according to the detection results, so that the extruder can tend to be dynamically stable.

[0100] In this embodiment, the set temperatures T1 and T2 are kept stable during the dynamic stabilization adjustment process. Only the extrusion parameters of the extruder are adjusted. The adjustment of a single parameter reduces the impact of fluctuations in other parameters and simplifies the parameter adjustment process of the extrusion process.

[0101] Example 2

[0102] This embodiment also discloses a self-healing PVC-U injection molding grade modified material, comprising a base material and self-healing microcapsules. The components of the base material, by mass parts, include:

[0103] 80 parts of PVC resin;

[0104] 20 parts of ultra-low polymerization degree PVC;

[0105] 5 parts calcium-zinc stabilizer;

[0106] 1 part lubricant;

[0107] Two parts of ACR resin;

[0108] 10-15 parts of nano-calcium carbonate;

[0109] The self-healing microcapsules are 5-10 wt%.

[0110] The PVC resin is SG-8 type PVC resin; the average degree of polymerization of ultra-low degree PVC is below 300; the lubricant can be calcium stearate or zinc stearate.

[0111] In this embodiment, the preparation steps of the self-healing microcapsules include:

[0112] Step B1: Mix epoxy resin E-51 and dicyandiamide curing agent at a mass ratio of 10:1, add coupling agent KH-550 at a mass ratio of 0.5%, and then ultrasonically disperse until uniform.

[0113] Step B2: Using in-situ polymerization, methyl methacrylate (MMA) monomer, crosslinking agent divinylbenzene (DVB) and initiator AIBN are dissolved in the aqueous phase and reacted at 60°C for 6 hours to form microcapsules with PMMA shells encapsulating the core material.

[0114] Step B3: After filtration, washing and drying, microcapsules with a particle size of 80-120μm are selected for use.

[0115] In this embodiment, the preparation steps of the self-healing PVC-U injection molding grade modified material include:

[0116] Step A1: Mix PVC resin, ultra-low degree polymer PVC, calcium-zinc stabilizer, lubricant, ACR resin, and nano calcium carbonate in the specified proportions; set the temperature to 82-88℃ during the mixing process; control the mixing speed to be greater than 150 rpm.

[0117] Step A2: Add self-healing microcapsules to the mixture from Step A1 and mix the self-healing microcapsules; the self-healing microcapsules should account for 5-10 wt% of the total mixture.

[0118] The self-healing microcapsule mixing process employs low-speed mixing, with the mixing speed controlled to be less than 50 rpm, to avoid the rupture of the self-healing microcapsules during the mixing process;

[0119] Step A3: Extrude and granulate the mixed material from step A2 to obtain self-healing PVC-U injection molding grade modified material;

[0120] In the extrusion granulation process, an extruder is used for extrusion, and the temperature at the exit of the die section of the extruder is controlled at 150℃, with an allowable temperature threshold difference of ±2℃, specifically ranging from 148℃ to 152℃.

[0121] The modified material is extruded through an extruder. The extruder is equipped with an extrusion die, which can form the extruded material into a strip structure. The extruded material is extruded along the extrusion channel, which includes a feeding section, a compression section, a homogenization and metering section, a pre-extrusion section, and a die section. During the extrusion process, the extruded material is first preheated in the pre-extrusion section to heat the temperature to a relatively constant state, and then it is extruded through the die section.

[0122] In the production process, self-healing materials are usually mixed with other PVC substrates to obtain self-healing masterbatch that can be injection molded. The content of microcapsules in the self-healing masterbatch is relatively high, and the extrusion temperature needs to be strictly controlled. When the extrusion temperature is too high, it is easy to damage the outer shell material, which can easily cause the self-healing material to agglomerate and affect the dispersibility of the self-healing material in subsequent production processes. On the other hand, if the base temperature is too low, it will affect the normal extrusion granulation process.

[0123] During the extrusion process, the material extrusion temperature control method in Example 1 is used to control the extrusion temperature, so that the extrusion temperature of the extruded material can be dynamically balanced and adjusted during the extrusion process.

[0124] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A self-healing PVC-U injection molding grade modified material, characterized in that, The material includes a base material and self-healing microcapsules, wherein the components of the base material, by mass parts, include: 80 parts of PVC resin; 20 parts of ultra-low polymerization degree PVC; 5 parts calcium-zinc stabilizer; 1 part lubricant; Two parts of ACR resin; 10-15 parts of nano-calcium carbonate; The self-healing microcapsules are 5-10 wt%.

2. The self-healing PVC-U injection molding grade modified material according to claim 1, characterized in that, The preparation steps of the self-healing PVC-U injection molding grade modified material include: Step A1: Mix PVC resin, ultra-low polymerization degree PVC, calcium-zinc stabilizer, lubricant, ACR resin, and nano calcium carbonate in the specified proportions. Step A2: Add self-healing microcapsules to the mixture from step A1 and mix the self-healing microcapsules. Step A3: Extrude and granulate the mixed material from step A2 to obtain self-healing PVC-U injection molding grade modified material.

3. The self-healing PVC-U injection molding grade modified material according to claim 2, characterized in that, In step A1, the temperature is set at 82-88℃ during mixing; in step A2, the mixing and stirring speed is controlled at 100-150 rpm; in step A2, the self-healing microcapsules in the mixture are 5-10 wt%; In step A3, the modified material is extruded using an extruder. The extruder is equipped with an extrusion die, which can form the extruded material into a strip structure.

4. The self-healing PVC-U injection molding grade modified material according to claim 1, characterized in that, The PVC resin is SG-8 type PVC resin; the average degree of polymerization of the ultra-low degree PVC is below 300; the lubricant is calcium stearate or zinc stearate.

5. The self-healing PVC-U injection molding grade modified material according to claim 1, characterized in that, The preparation steps of the self-healing microcapsules include: Step B1: Mix epoxy resin and dicyandiamide curing agent at a mass ratio of 10:1, add 0.5% coupling agent, and then ultrasonically disperse until uniform. Step B2: Using in-situ polymerization, methyl methacrylate monomer, crosslinking agent divinylbenzene and initiator AIBN are dissolved in the aqueous phase and reacted at 60°C for 6 hours to form microcapsules with PMMA shells encapsulating the core material. Step B3: After filtration, washing and drying, microcapsules with a particle size of 80-120μm are selected for use.

6. A method for controlling the extrusion temperature of a material, characterized in that, The material is extruded through an extruder. The extruder is equipped with an extrusion die, which can form the extruded material into a strip structure. The material is extruded along the extrusion channel. It first passes through the preheating section of the extrusion section to heat the temperature to a stable state, and then passes through the die section for extrusion. The control method includes the following steps: Step 1: Based on the extrusion requirements of the material, obtain the theoretical design temperature of the material at the exit of the die section as T0, and the theoretical design extrusion speed of the extruder as N; Step 2: The set temperature of the die section is T1, and the set temperature of the extrusion front section is T2, and T1>T2; The temperature difference between T1 and T2 is P, where P = T1 - T2; Step 3: During the extrusion process, the actual temperature T3 at the exit of the die section is detected and recorded at every time interval s; Let i represent the number of tests. The actual temperature detected during the i-th test is denoted as T3(i), and the current extrusion speed of the extruder is N(i). The initial value of i is 0, and each detection is recorded as i = i + 1; Step 4: Calculate the difference ΔT(i) between T0 and T3(i), where ΔT(i) = T3(i) - T0; Step 5: Adjust the extrusion speed of the extruder according to the relationship between ΔT(i) and the threshold range. The adjusted extrusion speed of the extruder is N(i+1). Step 6: The extruder operates at the adjusted extrusion speed N(i+1); Repeat steps 3, 4, and 5. If ΔT(i) is within the threshold range for three consecutive times, the extruder will operate in a stable state.

7. The method for controlling the material extrusion temperature according to claim 6, characterized in that, In step 5, the material generates a temperature rise during the extrusion process in the die section. The temperature rise is inversely proportional to the extrusion speed of the extruder and directly proportional to the difference P between the set temperatures T1 and T2. The temperature rise proportionality coefficient is k. The correlation of the adjusted extruder speed N(i+1) is as follows:

8. The method for controlling the material extrusion temperature according to claim 7, characterized in that, In step 5, α(i) is set as the speed adjustment coefficient of the extruder, and N(i+1)=(1+α(i))·N(i); The initial value of α(i) is α(0), α(0)=0.

9. The method for controlling the material extrusion temperature according to claim 6, characterized in that, In step 6, during steady-state operation, N(i+1) = (1 + σ1)·N(i); σ1 is the stability compensation coefficient, σ1=[50%·α(i)+30%·α(i-1)+20%·α(i-2)]·A; Set the temperature difference offset coefficient A, A=T3(i) / T2.

10. The method for controlling the material extrusion temperature according to claim 6, characterized in that, In step 6, if ΔT(i) exceeds the threshold range three times consecutively, the system will operate in a corrected state. When running in the corrected state, N(i+1) = (1 + σ2)·N(i); σ2 is the correction coefficient for the corrected state, σ2=[50%·α(i)+30%·α(i-1)+20%·α(i-2)] / A; Set the temperature difference offset coefficient A, A=T3(i) / T2.

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