Polytetrafluoroethylene anti-corrosion plastic forming equipment

Abstract

The invention discloses polytetrafluoroethylene anti-corrosion plastic forming equipment, and relates to the technical field of plastic forming, the polytetrafluoroethylene anti-corrosion plastic forming equipment comprises an injection molding unit, and the injection molding unit comprises a feeding assembly, a plurality of heat preservation assemblies arranged on the outer wall of the feeding assembly in a sleeving manner, auxiliary assemblies arranged on the outer walls of the heat preservation assemblies in a sleeving manner, and a material supply assembly fixed to one end of the feeding assembly. The device has the beneficial effects that precise conveying control over preheated PTFE powder and modified PTFE is achieved; the material displacement is accurately adjusted by controlling the distance between the screw rod and the injection molding nozzle, and the screw rod pair is used for controlling the injection molding assembly to axially move in the mold to ensure uniform distribution of materials.

Description

Technical Field

[0001] The invention relates to the technical field of plastic molding, in particular to polytetrafluoroethylene anti-corrosion plastic molding equipment. Background Art

[0002] As a representative of high-performance engineering plastics, polytetrafluoroethylene (PTFE) is widely used in aerospace, chemical industry, electronics and other fields due to its excellent chemical stability, electrical insulation and high temperature resistance. Contemporary PTFE molding technology mainly includes three technical paths: free extrusion, film casting and isostatic pressing. The free extrusion process forms a paste by mixing PTFE powder with an organic solvent, and then forms a PTFE product with an oriented structure through extrusion, devolatilization and sintering. This process loosens the grains in the PTFE matrix to form axial fibrils, enhancing the strength and rigidity of the product, but the process is cumbersome and has a heavy environmental burden. The film casting technology uses a PTFE aqueous dispersion system to coat the surface of the substrate, and achieves crystal melting and particle fusion through sintering. This coating process does not produce molecular orientation and has isotropic characteristics, but it is inefficient and the sedimentation of PTFE particles in the dispersion leads to uneven wall thickness. Isostatic pressing compresses PTFE powder under a multi-directional pressure field and then sinters to form a high-density PTFE matrix structure, but this process has high equipment requirements and is only applicable to products with relatively simple geometric shapes.

[0003] Centrifugal molding, as a potential PTFE processing method, can be used in PTFE powder centrifugal molding process and modified PTFE centrifugal molding process. However, the existing PTFE processing technology has multi-dimensional technical limitations when implementing centrifugal molding. First, the traditional conveying mechanism is used for the measurement accuracy and pressure stability of modified PTFE materials, resulting in a significant molding density gradient. Secondly, the axial distribution control mechanism is missing. In the production process of tubular or cylindrical PTFE products, the uneven distribution of materials along the axial direction directly affects the performance consistency. Third, due to the extremely high viscosity characteristics of PTFE and its modified system, the conventional displacement control method that relies on pressure regulation is difficult to apply, and there is a lack of effective mechanism to achieve precise displacement regulation. In addition, the energy recycling rate is low, and the high-temperature heat required for PTFE sintering is difficult to achieve cascade utilization in traditional equipment. Most importantly, the separation of molding and surface treatment processes leads to a lengthy process chain, and the low surface energy of PTFE makes it difficult for post-treatment coatings to adhere, which increases production complexity and environmental burden, which is particularly unfavorable for PTFE products that require anti-corrosion functions. Summary of the invention

[0004] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the object of the present invention is to provide a polytetrafluoroethylene anti-corrosion plastic molding equipment, which can solve the problems mentioned in the background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a polytetrafluoroethylene anti-corrosion plastic molding device, which includes an injection molding unit, including a feeding component, a plurality of insulation components sleeved on the outer wall of the feeding component, an auxiliary component sleeved on the outer wall of the insulation component, and a feeding component fixed to one end of the feeding component; The feeding assembly includes an injection molding shell, a screw rod sleeved on the inner wall of the injection molding shell, an adjusting head fixed to the end of the screw rod, a spring and a siphon ring sleeved on the outer wall of the adjusting head respectively, and an injection molding nozzle fixed to the end of the injection molding shell.

[0007] As a preferred solution of the polytetrafluoroethylene anti-corrosion plastic molding equipment of the present invention, wherein: the moving unit includes a screw pair and a support platform fixed to the outer wall of the threaded sleeve on the screw pair; A driving unit, comprising a push rod disposed on one side of the support platform, a slide rail fixed between the support platform and the push rod, a guide block sleeved on an outer wall of the slide rail, and a motor penetratingly disposed on one side of the guide block; The other end of the injection-molded shell is fixedly connected to the surface of the support platform, and the spiral rod passes through the center of the support platform and is fixedly connected to the motor shaft end.

[0008] As a preferred embodiment of the polytetrafluoroethylene anti-corrosion plastic molding equipment of the present invention, wherein: the injection molding shell is cylindrical and includes a mounting plate fixed to its outer wall; The regulating head is cone-shaped and includes a round rod fixed to one side thereof, a positioning block fixed to the outer wall of the round rod, and a through slot opened on the outer wall of the regulating head; The injection nozzle is cylindrical and includes a tapered opening at one end thereof.

[0009] As a preferred solution of the polytetrafluoroethylene anti-corrosion plastic molding equipment of the present invention, wherein: the feeding assembly includes an end cover, and a storage bin fixed to the side wall of the end cover; The end cover comprises a material gathering cavity arranged inside the end cover; the material storage bin is communicated with the material gathering cavity.

[0010] As a preferred solution of the polytetrafluoroethylene anti-corrosion plastic molding equipment of the present invention, the insulation component includes heating coils respectively sleeved on the injection nozzle and the outer wall of the injection shell, and an insulation shell sleeved on the outside of the heating coils.

[0011] As a preferred embodiment of the polytetrafluoroethylene anti-corrosion plastic molding equipment of the present invention, the auxiliary component includes a mounting ring fixed to one side of the injection nozzle, an atomizing nozzle fixed to the outer wall of the mounting ring, a guide shell fixed to the mounting plate, a sealing shell fixed to the guide shell, and a first delivery pipe and a second delivery pipe connected to the atomizing nozzle.

[0012] As a preferred solution of the polytetrafluoroethylene anti-corrosion plastic molding equipment described in the present invention, the guide shell includes a first inflation nozzle, a first exhaust nozzle and a first infusion nozzle opened on its outer wall, a plurality of second inflation nozzles, a plurality of second exhaust nozzles and a plurality of second infusion nozzles arranged on one side of the guide shell, and a plurality of confluence channels and a plurality of one-way channels opened inside the guide shell.

[0013] As a preferred embodiment of the polytetrafluoroethylene anti-corrosion plastic molding equipment of the present invention, the first inflation nozzle, the first exhaust nozzle, the first infusion nozzle, the second inflation nozzle, the second exhaust nozzle and the second infusion nozzle are respectively connected with one-way channels; The first inflation nozzle is connected to each of the second inflation nozzles through one of the confluences; the first air extraction nozzle is connected to each of the second air extraction nozzles through one of the confluences; the first infusion nozzle is connected to each of the second infusion nozzles through one of the confluences.

[0014] The beneficial effects of the present invention are as follows: the present invention realizes the precise conveying control of preheated PTFE powder and modified PTFE; accurately adjusts the material displacement by controlling the distance between the screw rod and the injection nozzle; utilizes the screw rod pair to control the axial movement of the injection molding component in the mold to ensure uniform distribution of the material; integrates centrifugal technology and vacuum defoaming to improve the material molding quality; reduces energy consumption by heat preservation and improves energy efficiency by utilizing waste heat; realizes the process integration of molding and surface treatment, significantly improves the product density uniformity and dimensional accuracy, reduces energy consumption, shortens the production cycle, and enhances the corrosion resistance of PTFE products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 It is an overall three-dimensional exploded view of the present invention.

[0017] Figure 2 It is an exploded view of the injection molding unit of the present invention.

[0018] Figure 3 It is an exploded view of the feeding assembly of the present invention.

[0019] Figure 4 It is an overall cross-sectional view of the present invention.

[0020] Figure 5 For the present invention Figure 4 A partial enlarged view.

[0021] Figure 6 It is a perspective view of the interior of the guide shell of the present invention.

[0022] Figure 7 It is a schematic diagram of centrifugal forming of the present invention.

[0023] Figure 8 It is an overall three-dimensional view of the present invention.

[0024] In the figure: 1. injection unit; 11. feeding assembly; 12. insulation assembly; 13. auxiliary assembly; 14. feeding assembly; 2. moving unit; 21. screw pair; 22. support platform; 3. driving unit; 31. push rod; 32. slide rail; 33. guide block; 34. motor; 111. injection shell; 112. screw rod; 113. adjustment head; 114. spring; 115. siphon ring; 116. injection nozzle; 1111. mounting plate; 1131. round rod; 1132. positioning block; 1133. through groove; 1161. tapered mouth; 141. end cover ; 142. Storage bin; 1411. Material gathering chamber; 121. Heating ring; 122. Insulation shell; 131. Mounting ring; 132. Atomizing nozzle; 133. Guide shell; 134. Sealing shell; 135. First delivery pipe; 136. Second delivery pipe; 1331. First inflation nozzle; 1332. First vacuum nozzle; 1333. First infusion nozzle; 1334. Second inflation nozzle; 1335. Second vacuum nozzle; 1336. Second infusion nozzle; 1337. Confluence channel; 1338. One-way channel; 4. Mold; 41. Sealing port; 42. Transmission shaft. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments. Example

[0028] Reference Figure 1 to Figure 8 , which is the first embodiment of the present invention, and provides a polytetrafluoroethylene anti-corrosion plastic molding device, which includes an injection molding unit 1, including a feeding component 11, a plurality of heat preservation components 12 sleeved on the outer wall of the feeding component 11, an auxiliary component 13 sleeved on the outer wall of the heat preservation component 12, and a feeding component 14 fixed to one end of the feeding component 11; The feeding assembly 11 includes an injection molding shell 111, a screw rod 112 sleeved on the inner wall of the injection molding shell 111, an adjusting head 113 fixed to the end of the screw rod 112, a spring 114 and a siphon ring 115 sleeved on the outer wall of the adjusting head 113 respectively, and an injection molding nozzle 116 fixed to the end of the injection molding shell 111.

[0029] Furthermore, the moving unit 2 includes a screw pair 21 and a support platform 22 fixed to the outer wall of the threaded sleeve on the screw pair 21; The driving unit 3 includes a push rod 31 disposed on one side of the support platform 22, a slide rail 32 fixed between the support platform 22 and the push rod 31, a guide block 33 sleeved on the outer wall of the slide rail 32, and a motor 34 penetratingly disposed on one side of the guide block 33; The other end of the injection-molded shell 111 is fixedly connected to the surface of the support platform 22 , and the spiral rod 112 passes through the center of the support platform 22 and is fixedly connected to the shaft end of the motor 34 .

[0030] Further, the injection molded shell 111 is cylindrical and includes a mounting plate 1111 fixed to its outer wall; The adjusting head 113 is cone-shaped, and includes a round rod 1131 fixed to one side thereof, a positioning block 1132 fixed to the outer wall of the round rod 1131, and a through slot 1133 opened on the outer wall of the adjusting head 113; The injection nozzle 116 is cylindrical and includes a tapered opening 1161 at one end thereof.

[0031] Furthermore, the feeding assembly 14 includes an end cover 141 and a storage bin 142 fixed to a side wall of the end cover 141; The end cover 141 includes a material gathering cavity 1411 disposed therein; the material storage bin 142 is communicated with the material gathering cavity 1411 .

[0032] Furthermore, the heat preservation component 12 includes a heating coil 121 which is respectively sleeved on the injection nozzle 116 and the outer wall of the injection shell 111 , and a heat preservation shell 122 which is sleeved on the outside of the heating coil 121 .

[0033] Furthermore, the auxiliary component 13 includes a mounting ring 131 fixed to one side of the injection nozzle 116, an atomizing nozzle 132 fixed to the outer wall of the mounting ring 131, a guide shell 133 fixed on the mounting plate 1111, a sealing shell 134 fixed on the guide shell 133, and a first delivery pipe 135 and a second delivery pipe 136 connected to the atomizing nozzle 132.

[0034] Furthermore, the flow guide shell 133 includes a first inflation nozzle 1331, a first air extraction nozzle 1332 and a first infusion nozzle 1333 opened on its outer wall, a plurality of second inflation nozzles 1334, a plurality of second air extraction nozzles 1335 and a plurality of second infusion nozzles 1336 arranged on one side of the flow guide shell 133, and a plurality of confluence channels 1337 and a plurality of one-way channels 1338 opened inside the flow guide shell 133.

[0035] Furthermore, the first inflation nozzle 1331, the first air extraction nozzle 1332, the first infusion nozzle 1333, the second inflation nozzle 1334, the second air extraction nozzle 1335 and the second infusion nozzle 1336 are respectively connected with a one-way channel 1338; the first inflation nozzle 1331 is connected with each second inflation nozzle 1334 through one of the confluence channels 1337; the first air extraction nozzle 1332 is connected with each second air extraction nozzle 1335 through one of the confluence channels 1337; the first infusion nozzle 1333 is connected with each second infusion nozzle 1336 through one of the confluence channels 1337.

[0036] It should be noted that the centrifugal molding process has significant technical necessity and process advantages for molding polytetrafluoroethylene PTFE and its modified system. Centrifugal molding technology uses the centrifugal force field generated by rotation to evenly distribute PTFE powder or modified PTFE on the inner wall of the mold, solving key technical defects such as uneven material distribution, wall thickness fluctuation and density gradient in traditional static pressure molding and film casting processes.

[0037] This process is particularly suitable for the production of axisymmetric PTFE anti-corrosion products in tubular and cylindrical shapes. The centrifugal force field can provide uniform compaction force that matches the geometry of the mold, significantly improving the uniformity of the material in the axial and radial directions, reducing internal stress, and making it easier to control the wall thickness accuracy.

[0038] In addition, the directional arrangement of materials in the centrifugal field can optimize the PTFE microstructure, enhance the comprehensive mechanical properties and air tightness of the product, especially the surface density which is crucial to improving the anti-corrosion performance. Centrifugal molding also makes the mold filling more thorough, reduces pores and interface defects, provides an ideal basis for subsequent surface treatment, and can be organically combined with surface coating technology to achieve process integration, significantly improve production efficiency, and reduce energy consumption and environmental burden. Therefore, the use of centrifugal molding technology is an innovative technical path for the preparation of high-performance PTFE anti-corrosion plastic products, which is of great significance for solving the problems of poor material uniformity, high process energy consumption, and low production efficiency in the existing technology.

[0039] Preferably, the screw sleeve in the screw pair 21 is provided with a threaded sleeve, and a through hole for accommodating the threaded sleeve is opened at the center below the support platform 22, and the two are fixedly connected by bolts, and two through holes for cooperating with the two cylindrical guide rails of the screw pair 21 are opened on both sides below the support platform, so that the screw pair 21 rotates through the screw to make the support platform 22 perform stable axial movement.

[0040] Preferably, two symmetrically distributed slide rails 32 are fixed on the surface of the support platform 22 , that is, the upper end of the screw pair 21 , and a push rod 31 is fixed on the other end of the slide rail 32 .

[0041] Preferably, the push rod 31 is fixed on a plate, the slide rail 32 is fixedly connected to the plate, and the execution end of the push rod 31 passes through the plate.

[0042] As an optional implementation, the push rod 31 may be a hydraulic push rod.

[0043] As an optional implementation, the push rod 31 may be an electric push rod.

[0044] Preferably, guide blocks 33 are sleeved on the outer walls of the two slide rails 32, and the motor 34 is fixed on the side facing the push rod 31, and the shaft end passes through the guide block 33, so that the guide block 33 can drive the motor 34 to move axially on the slide rail 32. In addition, the tail of the motor 34 is fixedly connected to the execution end of the push rod 31.

[0045] Preferably, a fixed bracket is fixed on one side of the motor 34 on the guide block 33, and the fixed bracket is fixedly connected to the execution end of the push rod 31, so when the push rod 31 is extended or retracted, it can drive the motor 34 to move axially.

[0046] It should be noted that the screw pair 21 can drag the support platform 22 and the driving unit 3 as a whole to move axially.

[0047] Preferably, the injection molded shell 111 is in the shape of a long cylinder, and a mounting plate 1111 is fixed on the outer wall of one end thereof. The injection molded shell 111 is fixed on one side of the support platform 22 and faces away from the motor 34. Specifically, the mounting plate 1111 is fixedly connected to the surface of the support platform 22 by bolts, and the end of the injection molded shell 111 with the mounting plate 1111 passes through the inside of the support platform 22. On the other side of the support platform 22, an end cover 141 is fixed, and a material collection cavity 1411 is provided inside the end cover 141. Both sides of the material collection cavity 1411 are connected, and one side is connected to the inner cavity of the injection molded shell 111. A feed port that passes through to the outside is also provided on the inner wall of the material collection cavity 1411, and the storage bin 142 is connected to the feed port through a pipeline.

[0048] Preferably, the storage bin 142 is used to store PTFE powder and modified PTFE, which are collectively referred to as PTFE raw materials in this application.

[0049] PTFE powder is usually a white fine granular substance with high viscosity, high crystallinity and low surface energy. Its particle size and morphology have a direct impact on the density and uniformity of the final molded product. In the traditional PTFE powder centrifugal molding process, the powder usually needs to be preheated to reduce the friction between particles and improve the fluidity and uniform distribution ability in the centrifugal field.

[0050] Modified PTFE improves the processing performance and specific functionality of PTFE by adding flow modifiers or functional fillers. Although this type of modified system improves the flow characteristics of PTFE, it still has significant non-Newtonian fluid behavior and high viscoelasticity.

[0051] It should be noted that the PTFE raw material can enter the material collection chamber 1411 through the storage bin 142 .

[0052] As an optional implementation, the storage bin 142 may be a storage tank for pre-storing PTFE raw materials. During the centrifugal molding process, the storage bin 142 may be continuously replaced to achieve the purpose of continuous material supply.

[0053] As an optional embodiment, the storage bin 142 may be a funnel-shaped open bin body, into which raw materials may be continuously injected from the outside.

[0054] Preferably, a spiral rod 112 is sleeved inside the injection molding shell 111, one end of the spiral rod 112 is immersed in the injection molding shell 111, and the other end passes through the injection molding shell 111 and the material collection cavity 1411 to the outside of the end cover 141, and is fixedly connected to the motor 34. Specifically, the spiral rod 112 is fixedly connected to the shaft end of the motor 34 through a coupling.

[0055] It should be noted that the local spiral guide groove on the body of the spiral rod 112 is always located inside the material collection chamber 1411 during the entire centrifugal molding process, thereby ensuring the timely supply of PTFE raw materials.

[0056] Preferably, an adjusting head 113 is fixed to one end of the screw rod 112 immersed in the injection molded shell 111. Specifically, the adjusting head 113 is conical with the tip of the cone facing outward, and a round rod 1131 is fixed to the bottom surface of the adjusting head 113. A plurality of positioning blocks 1132 are distributed in an array and fixed on the outer wall of the round rod 1131, and a plurality of through grooves 1133 are opened on the outer wall of the adjusting head 113 to increase the conveying space of the PTFE raw material. The round rod 1131 is coaxial with the screw rod 112 and is inserted into the end of the screw rod 112 and fixedly connected by side bolts.

[0057] It should be noted that only when the screw pair 21 is working can the injection molded shell 111 be moved axially; only when the motor 34 is driven can the screw rod 112 be dragged to rotate to ensure the continuous transportation of the PTFE raw material in the injection molded shell 111, and at this time the injection molded shell 111 and the screw rod 112 will not change position; only when the push rod 31 is working can the motor 34 and the screw rod 112 be driven to move axially synchronously, and at this time the injection molded shell 111 and the screw rod 112 will change position.

[0058] Preferably, a spring 114 and a siphon ring 115 are also sleeved on the round rod 1131 of the adjusting head 113. Specifically, the spring 114 and the siphon ring 115 are sequentially sleeved from the adjusting head 113 to the position of the positioning block 1132. The spring 114 acts on the siphon ring 115 and makes the siphon ring 115 press against the positioning block 1132, while the outer wall of the siphon ring 115 fits against the inner wall of the injection molded shell 111.

[0059] It should be noted that an annular protrusion with a diameter larger than the diameter of the round rod 1131 is provided at the connection between each positioning block 1132 and the round rod 1131, and the inner wall of the siphon ring 115 is fitted with the outer wall of the annular protrusion, ensuring that the PTFE raw material can pass through the gap between the inner wall of the siphon ring 115 and the outer wall of the round rod 1131, and at the same time ensuring that the siphon ring 115 also has the effect of sealing the inner cavity of the injection molded shell 111.

[0060] Specifically, when the PTFE raw material is transported to the position of the siphon ring 115, the siphon ring 115 overcomes the action of the spring 114 and shifts. At this time, a gap is formed between the inner wall of the siphon ring 115 and the round rod 1131. When the PTFE raw material is no longer transported, specifically modified PTFE is referred to here. Since the modified PTFE still has non-Newtonian fluid behavior, the siphon ring 115 is pushed to the aforementioned annular protrusion under the slow action of the spring 114. At this time, the inner cavity of the injection molding shell 111 is closed. At this time, the push rod 31 drags the screw rod 112 to move axially toward the direction of the motor 34. Since the siphon ring 115 blocks the inner cavity of the injection molding shell 111, the modified PTFE raw material inside the injection molding nozzle 116 can be driven by the siphon ring 115 to reflux a short distance, or prevent the modified PTFE from overflowing.

[0061] Preferably, an injection nozzle 116 is fixed to the outward end of the injection shell 111, and the injection nozzle 116 has a cylindrical and bidirectionally penetrating inner cavity. Specifically, the injection nozzle 116 is fixed to the end of the injection shell 111 by a threaded connection, and the injection nozzle 116 is provided with a tapered opening 1161 at the opening facing the adjusting head 113. When the screw rod 112 moves axially, the adjusting head 113 moves axially therewith, so that the distance between the screw rod 112 and the tapered opening 1161 can be adjusted, thereby achieving the control of the discharge amount of the PTFE raw material.

[0062] It should be noted that the modified PTFE in the injection molded shell 111 needs to maintain a constant pressure. Although the modified PTFE has improved processing performance by adding flow aids, its melt still has significant non-Newtonian fluid properties and high viscoelasticity. Pressure fluctuations can cause abnormal material flow behavior, resulting in uneven cross-sectional density and wall thickness fluctuations, as well as unstable displacement. In addition, separation or migration is prone to occur under a variable pressure environment. A constant pressure environment is a necessary condition for maintaining uniform distribution of additives.

[0063] It should be noted that the traditional way to control the discharge amount of PTFE raw material is to control the rotation speed of the screw rod 112. When the screw rod 112 is conveying the modified PTFE, under the condition of internal constant pressure, it is necessary to consider the influence of the rotation speed of the screw rod 112 on the modified PTFE. In the low speed area, the displacement and the rotation speed are approximately linearly related; in the medium speed area, the displacement growth rate decreases; in the high speed area, due to shear thinning and elastic effects, the displacement growth tends to saturation or even decreases, the filler may be oriented or separated, and the modified PTFE may undergo a viscosity mutation.

[0064] Therefore, by precisely controlling the axial spacing between the end of the screw rod 112 and the injection nozzle 116, the cross-sectional area of ​​the discharge channel can be precisely adjusted, thereby achieving high-precision control of the displacement of the modified PTFE. This adjustment method has a rapid response and precise control, and is particularly suitable for fine adjustment under fixed equipment parameters. In addition, there is a compensation relationship between the variables under constant pressure conditions. When the cross-sectional area increases, the rotation speed needs to be reduced, and the temperature can be appropriately reduced at this time.

[0065] Taking into account the effect of temperature change on the viscosity of modified PTFE, the compensation relationship at this time should be satisfied. When the temperature rises, the viscosity of modified PTFE decreases. At this time, the cross-sectional area needs to be reduced or the rotation speed needs to be reduced.

[0066] Preferably, a plurality of heating coils 121 are fixed on the injection nozzle 116 and the outer wall of the injection molding shell 111. The distribution spacing and number of the heating coils 121 are related to the power of the heating coils 121 and the length of the injection molding shell 111. They are used for heating the injection nozzle 116 and gradient heating or stable heating of the injection molding shell 111, respectively. An insulation shell 122 is also sleeved on the outer wall of the heating coil 121 on the injection molding shell 111. Specifically, the inner wall of the insulation shell 122 is in contact with the heating coil 121 and the outer wall of the injection molding shell 111.

[0067] As for PTFE powder, a gradual temperature gradient can be created by the heating ring 121, which can avoid local uneven melting caused by sudden temperature changes of the PTFE powder, while the insulation shell 122 can eliminate the influence of external cold spots and prevent the powder from forming an uneven layered structure on the injection tube wall.

[0068] For modified PTFE, the heating ring 121 can achieve a temperature gradient to prevent the filler from being segregated or oriented during the flow process, while the insulation shell 122 can ensure more precise temperature control in multiple stages to ensure clear boundaries between each temperature zone.

[0069] Preferably, a mounting ring 131 is fixed at a position adjacent to the injection nozzle 116 . Specifically, the mounting ring 131 is sleeved and fixed on the outer wall of the outward end of the injection shell 111 , and at least three atomizing nozzles 132 distributed circumferentially are fixed on the side wall of the mounting ring 131 .

[0070] As an optional embodiment, the atomizing nozzle 132 adopts a double-headed atomizing nozzle, which can reduce the number of atomizing nozzles 132 and greatly ensure the coverage of the spraying range.

[0071] Preferably, the guide shell 133 is fixed on one side of the mounting plate 1111, and is fixed in the form of a threaded connection in the present application. The first air filling nozzle 1331 and the first infusion nozzle 1333, which are consistent in number with the atomizing nozzle 132, are fixed on the end face of the guide shell 133, and the atomization of the atomizing nozzle 132 requires the synchronous input of high-pressure air and liquid medium to achieve the atomization effect of the liquid medium. In the present application, a single atomizing nozzle 132 is fixedly connected to the first air filling nozzle 1331 and the first infusion nozzle 1333 through the first delivery pipe 135 and the second delivery pipe 136, respectively, and each forms a transport channel. In addition, the first vacuum nozzle 1332 is also fixed on the end face of the guide shell 133 for vacuuming in subsequent processes.

[0072] Each of the first inflation nozzles 1331, the first air extraction nozzles 1332 and the first infusion nozzles 1333 is connected to a one-way channel 1338 opened inside the flow guide shell 133, and each of the one-way channels 1338 is not connected to each other. Three mutually unconnected confluence channels 1337 are opened at different positions inside the flow guide shell 133, and each confluence channel 1337 is connected to all the first inflation nozzles 1331 or the first air extraction nozzles 1332 or the first infusion nozzles 1333 through each one-way channel 1338, that is, each confluence channel 1337 only plays a single role, such as inflation, air extraction and delivery of liquid medium.

[0073] In addition, at least one second air-inflating nozzle 1334, a second air-exhausting nozzle 1335, and a second infusion nozzle 1336 are fixed to the side wall of the flow-guiding shell 133, and each of the second air-inflating nozzle 1334, a plurality of second air-exhausting nozzles 1335, and a plurality of second infusion nozzles 1336 is also connected to a one-way passage 1338 opened inside the flow-guiding shell 133, and each of the one-way passages 1338 is not connected to each other. At the same time, the second air-inflating nozzle 1334, the second air-exhausting nozzle 1335, and the second infusion nozzle 1336 are connected to each confluence passage 1337 through the one-way passage 1338, that is, the second air-inflating nozzle 1334 is connected to a plurality of first air-inflating nozzles 1331, and the second air-exhausting nozzle 1335 and the second infusion nozzle 1336 are similar.

[0074] It should be noted that the second inflation nozzle 1334 is connected to an air compressor, the second air exhaust nozzle 1335 is connected to a vacuum pump, and the second infusion nozzle 1336 is connected to a spray liquid supply device.

[0075] It should be noted that the types and purposes of the spraying liquid used in different centrifugal molding processes are different. For the centrifugal molding process of PTFE powder, the spraying liquid should use fluoride-based coatings or modified silicone coatings, which can enhance the wettability and adhesion of the inner surface of PTFE, facilitate subsequent assembly, and provide special functions such as antistatic and conductivity while maintaining the basic properties of PTFE. At the same time, it seals the fine pores formed during the sintering process of PTFE to improve the air tightness of the product. In addition, it provides a uniform and smooth inner surface to reduce the resistance of the fluid passing through. For the centrifugal molding process of modified PTFE, the use of epoxy-fluororesin composite system or functionalized polyester coating can compensate for the uneven distribution of the modifier on the surface of the modified PTFE, and can also seal the surface defects that may be caused by the introduction of flow aids, while providing a chemical barrier with the external environment to prevent the migration of the modifier.

[0076] Preferably, a sealing shell 134 is also fixed on the outer wall of the guide shell 133. The sealing shell 134 is determined according to the length of the mold 4 and can fit tightly with the sealing port 41 of the mold 4 to prevent the sealing shell 134 from failing to reach the sealing port 41 due to the mold 4 being too short, resulting in the inability to perform the vacuum operation.

[0077] It should be noted that during the molding stage, the mold 4 is vacuumed, and when PTFE powder is used, the air between the powder particles can be removed to prevent the formation of micropores in the finished product, and a higher material density can be obtained under the coordination of centrifugal force, and internal stress can be reduced to reduce the risk of subsequent deformation; when modified PTFE is used, microbubbles at the interface of the matrix can be removed, and carbon-based and metal-based fillers can be protected from high-temperature oxidation, and the close bonding between the filler and the matrix can be enhanced, while removing volatile substances that may be generated by the filler treatment agent or the interface agent. Example

[0078] Reference Figure 7 , which is the second embodiment of the present invention, provides a method for molding polytetrafluoroethylene anti-corrosion plastic, which adopts a centrifugal molding process, including a mold 4, a sealing port 41 opened on one side of the mold 4, and a transmission shaft 42 fixed to the end face of the other side of the mold 4.

[0079] It should be noted that the mold 4 needs to be connected to a driving source, such as a motor, and fixedly connected to the transmission shaft 42 to ensure the rotational centrifugal effect of the mold 4.

[0080] It should be noted that, during the centrifugal forming process, the raw material is first transported to the feeding assembly 11 through the precise metering system of the screw rod 112, and the material separation caused by pressure fluctuation is avoided by constant pressure control, and then the displacement is precisely controlled by the regulating head 113 with adjustable spacing, and then the material is injected into the rotating mold 4. Under the action of the centrifugal field, the material is evenly distributed on the inner wall of the mold 4 and forms an initial shape.

[0081] During the centrifugal process, PTFE powder mainly relies on mechanical interlocking between particles to form its initial structure, while the modified PTFE can obtain a more uniform spatial distribution of fillers or modifiers under the action of the centrifugal field.

[0082] Compared with traditional pressure molding, centrifugal molding uses the centrifugal force field to provide directional compaction force that matches the mold geometry, effectively solving the problems of uneven axial distribution and wall thickness fluctuations, while improving the density uniformity and surface quality of PTFE products, laying the foundation for subsequent anti-corrosion treatment. Especially for tubular anti-corrosion products, by using the screw pair 21 to control the axial movement of the injection unit 1 in the mold 4, combined with the centrifugal force, it is possible to achieve dual uniform distribution of the material in the axial and radial directions, significantly improving the performance of the product.

[0083] Specifically, when using the PTFE powder centrifugal molding process, the PTFE powder needs to be fed into the aggregation chamber 1411 through the storage bin 142. The aggregation chamber 1411 needs to ensure that the powder supply is continuous and stable without interruption. The powder should be preheated to an appropriate temperature before entering to reduce friction between particles.

[0084] Then the motor 34 rotates at a constant speed and drives the screw rod 112 to operate. The spiral guide groove on the screw rod 112 is continuously located inside the material collection chamber 1411 to ensure the continuous delivery of the PTFE powder, and the regulating head 113 needs to coordinate with the distance between the conical mouth 1161 of the injection nozzle 116 to control the displacement. When the powder passes through the siphon ring 115, the spring 114 is compressed. At the same time, the heating coil 121 performs gradient heating on the injection shell 111 to construct a progressive temperature gradient. The insulation shell 122 mounted on the outside of the heating coil 121 is used to eliminate the influence of external cold spots and stabilize the temperature to avoid local uneven melting caused by sudden changes in the temperature of the PTFE powder.

[0085] Then the screw pair 21 rotates, driving the support platform 22 and the entire injection unit 1 to move axially. At the same time, powder is continuously and stably injected into the mold 4 to ensure that the powder is evenly distributed inside the mold 4. Then the injection nozzle 116 is aligned with the sealing port 41 of the mold 4 and precisely positioned until the sealing shell 134 and the sealing port 41 of the mold 4 are tightly matched to form a seal, and then the powder injection is stopped.

[0086] Subsequently, the mold 4 rotates constantly at high speed to generate a stable centrifugal force field, and the PTFE powder is evenly distributed on the inner wall of the mold under the action of centrifugal force. Since the second air suction nozzle 1335 is connected to the vacuum pump, an air suction channel is formed through the confluence channel 1337, the one-way channel 1338 and the first air suction nozzle 1332, and the inside of the mold 4 is continuously vacuumed to remove the air between the powder particles, ensuring sintering in a vacuum environment, avoiding oxidation, and improving the density of the product.

[0087] The temperature of mold 4 needs to be maintained in the range of 340-380°C. At high temperature, the interface between PTFE powder particles melts to form an overall structure. Thereafter, an appropriate sintering time is maintained to ensure that the PTFE is fully crystallized and the structure is stable.

[0088] Next, the push rod 31 drives the motor 34 and the screw rod 112 to move axially in the opposite direction, the injection nozzle 116 gradually withdraws, and the second inflation nozzle 1334 and the second infusion nozzle 1336 provide compressed air and fluoride-based coating to the atomizing nozzle 132 through the confluence channel 1337 and the one-way channel 1338. Specifically, the atomizing nozzle 132 atomizes the coating through the first delivery pipe 135 and the second delivery pipe 136 and sprays it on the inner surface of the product. At this time, the surface coating fills the fine pores, which can improve the air tightness of the product.

[0089] Finally, the mold temperature is reduced at an appropriate rate to avoid deformation caused by thermal stress. After reaching the demoulding temperature, the mold is opened and the finished product is taken out. The finished product completes the manufacturing process after post-processing inspection.

[0090] When using the modified PTFE centrifugal molding process, the surface-treated modified PTFE is transported from the storage bin 142 to the material collection chamber 1411 to ensure that the filler and the PTFE matrix are pre-mixed evenly without separation. If the raw material has a suitable loose filling density, the subsequent processing stability can be guaranteed.

[0091] Subsequently, the motor 34 drives the screw rod 112 at a speed lower than that of the PTFE powder process to ensure low shear force conveying to reduce the directional arrangement of the filler during the flow process, and then accurately controls the distance between the regulating head 113 and the tapered mouth 1161 of the injection nozzle 116, while maintaining a constant pressure to prevent the filler from separating or migrating.

[0092] At the same time, the heating ring 121 needs to perform multi-stage precise temperature control to form a clear temperature gradient, and the insulation shell 122 is used to ensure clear boundaries between temperature zones to prevent filler segregation. The temperatures in the feeding zone, middle section, and discharging zone need to be precisely controlled within specific ranges.

[0093] Subsequently, the screw pair 21 drives the injection unit 1 to move axially more finely, so that the injection nozzle 116 is accurately aligned with the mold 4. During this process, the modified PTFE is evenly and continuously injected into the inner wall of the mold 4. Due to the high viscosity of the modified PTFE, the modified PTFE needs to be continuously distributed in the axial direction of the mold 4 until the sealing shell 134 reaches and forms a high vacuum sealing interface with the sealing port 41 of the mold 4. At this time, the discharge of the modified PTFE is interrupted, and the siphon ring 115 will control the reflux of the modified PTFE under the action of the spring 114 to prevent overflow.

[0094] Then the mold 4 rotates at a relatively low speed to ensure the initial uniform distribution of the modified PTFE, and then increases the speed to increase the centrifugal force to achieve material densification, while intermittently adding pulsed short acceleration to prevent the high-density filler from settling.

[0095] Next, an efficient vacuum system is formed by the second vacuum nozzle 1335, the confluence channel 1337, the one-way channel 1338 and the first vacuum nozzle 1332. Specifically, a short-term strong vacuum is performed in the early stage of molding to remove most of the gas, and a long-term slow vacuum is performed in the middle stage of sintering to deal with microbubbles at the interface between the filler and the matrix.

[0096] During the sintering process, the mold temperature adopts a step-by-step heating strategy and is controlled in multiple temperature intervals. Each temperature interval is maintained for a specific time to ensure that the filler and the matrix interface are fully combined. In particular, the time control of the high-temperature section needs to be more precise to avoid degradation of the filler and matrix interface.

[0097] After that, the push rod 31 controls the screw rod 112 to move in the opposite axial direction, and the injection nozzle 116 withdraws. At the same time, the epoxy-fluororesin composite system coating is delivered through the second infusion nozzle 1336, and the atomizing nozzle 132 receives the compressed air and coating delivered by the first delivery pipe 135 and the second delivery pipe 136 and atomizes the coating to achieve uniform spraying. It should be noted that coating at a lower temperature can compensate for the uneven distribution of the modifier.

[0098] Finally, during the demoulding stage, the cooling rate needs to be strictly controlled to prevent microcracks caused by thermal stress. During the cooling process, an appropriate vacuum degree must be maintained to avoid the formation of secondary bubbles. When the demoulding temperature is reached, the finished product is taken out and the surface quality and filler distribution are tested.

[0099] In summary, the present application can be applied to PTFE powder and modified PTFE centrifugal molding processes at the same time, and different process requirements can be achieved through the same basic device. Both processes transport raw materials from the storage bin 142, meter and transport through the screw rod 112, and use the centrifugal force generated by the rotation of the mold to achieve uniform distribution of materials. Finally, sintering and molding are carried out under a vacuum environment and surface spraying treatment is performed, but there are significant differences in specific control. The PTFE powder process adopts uniform high-speed conveying, constant centrifugal speed and single temperature zone control, while the modified PTFE process implements low-speed conveying to reduce filler shear orientation, adopts variable speed centrifugal curve to prevent filler sedimentation, and also performs multi-stage fine temperature control and step-type sintering. Both processes can achieve improved material distribution uniformity, precise displacement control and process integration, but the modified PTFE process pays more attention to filler distribution improvement, interface bonding optimization and thermal stress management, which effectively solves the problems of uneven material distribution and poor interface bonding in traditional PTFE processing, and provides technical guarantee for the preparation of high-performance PTFE anti-corrosion products.

[0100] Compared with traditional molding processes, the free extrusion process is cumbersome and has a heavy environmental burden, the casting film technology is inefficient and has uneven wall thickness, the isostatic pressing equipment has high requirements and the geometric shape is limited. This application adopts a centrifugal molding process, which can adjust the displacement of raw materials through dynamic spacing, evenly distribute axially in the mold, and eliminate bubbles through a vacuum environment to increase density. At the same time, it integrates the molding and surface spraying processes, thereby shortening the process chain and reducing the environmental burden.

[0101] In particular, in order to address the problem that the low surface energy of PTFE makes it difficult for the coating to adhere, the present application significantly improves the surface treatment effect by spraying the coating under a vacuum environment, providing a complete solution for the efficient preparation of high-performance PTFE and modified PTFE anti-corrosion products.

[0102] It is important to note that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A polytetrafluoroethylene anti-corrosion plastic molding equipment, characterized in that: include, The injection molding unit (1) comprises a feeding component (11), a plurality of heat-insulating components (12) sleeved on the outer wall of the feeding component (11), an auxiliary component (13) sleeved on the outer wall of the heat-insulating component (12), and a feeding component (14) fixed to one end of the feeding component (11); The feeding assembly (11) comprises an injection molding shell (111), a screw rod (112) sleeved on the inner wall of the injection molding shell (111), an adjusting head (113) fixed to the end of the screw rod (112), a spring (114) and a siphon ring (115) sleeved on the outer wall of the adjusting head (113), and an injection molding nozzle (116) fixed to the end of the injection molding shell (111).

2. The polytetrafluoroethylene anti-corrosion plastic molding equipment according to claim 1, characterized in that: The moving unit (2) comprises a screw pair (21) and a support platform (22) fixed to the outer wall of a threaded sleeve on the screw pair (21); A driving unit (3) comprising a push rod (31) arranged on one side of the support platform (22), a slide rail (32) fixed between the support platform (22) and the push rod (31), a guide block (33) sleeved on an outer wall of the slide rail (32), and a motor (34) arranged through one side of the guide block (33); The other end of the injection-molded shell (111) is fixedly connected to the surface of the support platform (22), and the spiral rod (112) passes through the center of the support platform (22) and is fixedly connected to the shaft end of the motor (34).

3. The polytetrafluoroethylene anti-corrosion plastic molding equipment according to claim 2, characterized in that: The injection-molded shell (111) is cylindrical and comprises a mounting plate (1111) fixed to its outer wall; The regulating head (113) is conical, and comprises a round rod (1131) fixed to one side thereof, a positioning block (1132) fixed to the outer wall of the round rod (1131), and a through slot (1133) opened on the outer wall of the regulating head (113); The injection nozzle (116) is cylindrical and comprises a tapered opening (1161) opened at one end thereof.

4. The polytetrafluoroethylene anti-corrosion plastic molding equipment as claimed in claim 3, characterized in that: The material supply assembly (14) comprises an end cover (141) and a material storage bin (142) fixed to a side wall of the end cover (141); The end cover (141) comprises a material gathering cavity (1411) arranged inside the end cover; the material storage bin (142) is in communication with the material gathering cavity (1411).

5. The polytetrafluoroethylene anti-corrosion plastic molding equipment as claimed in claim 4, characterized in that: The heat-insulating component (12) comprises a heating ring (121) respectively sleeved on the injection nozzle (116) and the outer wall of the injection shell (111), and a heat-insulating shell (122) sleeved on the outside of the heating ring (121).

6. The polytetrafluoroethylene anti-corrosion plastic molding equipment according to claim 5, characterized in that: The auxiliary component (13) comprises a mounting ring (131) fixed to one side of the injection nozzle (116), an atomizing nozzle (132) fixed to the outer wall of the mounting ring (131), a guide shell (133) fixed to the mounting plate (1111), a sealing shell (134) fixed to the guide shell (133), and a first delivery pipe (135) and a second delivery pipe (136) connected to the atomizing nozzle (132).

7. The polytetrafluoroethylene anti-corrosion plastic molding equipment according to claim 6, characterized in that: The flow guide shell (133) comprises a first inflation nozzle (1331), a first air extraction nozzle (1332) and a first infusion nozzle (1333) which are opened on the outer wall thereof, a plurality of second inflation nozzles (1334), a plurality of second air extraction nozzles (1335) and a plurality of second infusion nozzles (1336) which are arranged on one side of the flow guide shell (133), and a plurality of converging channels (1337) and a plurality of one-way channels (1338) which are opened inside the flow guide shell (133).

8. The polytetrafluoroethylene anti-corrosion plastic molding equipment according to claim 7, characterized in that: The first inflation nozzle (1331), the first air extraction nozzle (1332), the first infusion nozzle (1333), the second inflation nozzle (1334), the second air extraction nozzle (1335) and the second infusion nozzle (1336) are respectively connected to a one-way channel (1338); The first inflation nozzle (1331) is in communication with each of the second inflation nozzles (1334) via one of the confluence channels (1337); The first air extraction nozzle (1332) is connected to each of the second air extraction nozzles (1335) via one of the confluence channels (1337); The first infusion nozzle (1333) is connected to each of the second infusion nozzles (1336) via one of the confluence channels (1337).

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