Antistatic polypropylene film and method of making

Abstract

The application provides an antistatic polypropylene film applied to a high polymer compound composition and a preparation method.The scheme utilizes static electricity to arrange the ball position in the antistatic layer, so that the balls can be relatively uniformly distributed on the surface of the antistatic layer away from the one end of the main body of the film, thereby enhancing the conductive performance of the polypropylene film precursor;the exposed carboxylated carbon fibers can absorb moisture in the outside world and form a water film;the water film between two adjacent carboxylated carbon fibers can be connected together when the outside environment is relatively humid, thereby forming a conductive area on the surface of the polypropylene film precursor, reducing the static electricity accumulation, and the static electricity of the static head is given as controllable, the distance between adjacent balls can be controlled, the performance of the polypropylene film precursor is adjusted, and the balls can be uniformly distributed on the surface of the polypropylene film precursor close to the base film in the production process, and the antistatic effect is increased.

Description

Technical Field

[0001] This application relates to polymer compound compositions, and more particularly to an antistatic polypropylene film and its preparation method. Background Technology

[0002] Polypropylene film is widely used in packaging materials. As the market continues to expand, the production and use of polypropylene film are developing towards high speed, high quality and automation. Due to the low conductivity of polypropylene film, charges tend to accumulate on the surface of the film. Therefore, the antistatic function of polypropylene film is particularly important for films that need to be used for a long time.

[0003] The main existing antistatic method for polypropylene films is to add antistatic masterbatch during the production process to increase the antistatic ability of the polypropylene film. In Chinese invention publication number CN113717470B, "A permanent antistatic masterbatch for polypropylene film and its preparation method and film" is disclosed, which includes: "using modified organosilicon microspheres as a permanent antistatic agent, the modified organosilicon microspheres are formed by grafting surface-treated carbon fibers onto the surface of organosilicon microspheres through esterification reaction to form an organosilicon microsphere-g-carbon fiber structure, one end of which is compatible with polypropylene, and the other end is uniformly dispersed in polypropylene"; utilizing the interfacial properties of the carbon fiber surface to dissolve in the polypropylene body, the organosilicon microspheres maintain their flow properties, so that they can be firmly embedded in the polypropylene body and not easily detached, while the carbon fibers form a three-dimensional interwoven network structure, thereby enhancing the conductivity of the entire film, which has permanent antistatic properties, and also has comprehensive properties such as good anti-adhesion, high dispersibility and low coefficient of friction.

[0004] The invention successfully solved the problem that carbon fiber cannot be completely dispersed when used alone as an antistatic material. However, similarly, although the "organosilicon microsphere-g-carbon fiber structure" with organosilicon microspheres as the core has solved the problem of poor flowability and inability to be uniformly dispersed in polypropylene fluid to a certain extent, the "organosilicon microsphere-g-carbon fiber structure" also cannot achieve uniform distribution, which can easily affect the antistatic properties of polypropylene film products. Summary of the Invention

[0005] The purpose of this application is to address the issue that the "organosilicon microsphere-g-carbon fiber structure" cannot achieve uniform distribution, which can easily affect the antistatic properties of polypropylene film products. Compared with existing technologies, this application provides a method for preparing an antistatic polypropylene film, which mainly includes the following steps: S1. Preparation of antistatic masterbatch, wherein the antistatic masterbatch includes spheres, each sphere comprising an organosilicon core, carboxylated carbon fibers, and an insulating shell. The surfaces of the organosilicon core and carboxylated carbon fibers are carboxylated, followed by esterification grafting. The carboxylated carbon fibers are grafted onto the surface of the carboxylated carbon fibers to obtain an organosilicon microsphere-g-carbon fiber structure. The organosilicon microsphere-g-carbon fiber structure is then added to the slurry of the insulating shell, allowing the slurry to penetrate into the gaps between the carboxylated carbon fibers. The organosilicon microsphere-g-carbon fiber structure is then removed and dried to constant weight to obtain the finished spheres. S2. Preparation of polypropylene slurry: Polypropylene is dissolved using a solvent and a dispersant is added. The pellets obtained in step S1 are then added to the liquid polypropylene to form a slurry. Homogenization is performed to ensure that the pellets are evenly dispersed in the polypropylene slurry, thus obtaining a mixed slurry. S3. Polypropylene film formation: The polypropylene slurry obtained in step S2 is fed into the film forming equipment for production. The film forming equipment includes a base film, a feeding section, a settling section, an electrostatic imparting section, an electrostatic finishing section, and a drying section. The mixed slurry obtained in step S2 is fed into the feeding section to form a polypropylene film precursor on the upper surface of the base film. S4. Anti-static masterbatch sedimentation: When the polypropylene film precursor and base film move into the sedimentation zone, the spheres in the polypropylene film precursor, due to their higher density than polypropylene, will sink to the interface between the polypropylene film precursor and the base film. S5. Electrostatic Imparting: When the polypropylene film precursor and the base film move to the range of the electrostatic imparting section, electrostatics are imparted to the end of the polypropylene film precursor near the base film, so that the end of the polypropylene film precursor near the base film and the outer surface of the insulating spherical shell are in a charged state. S6. Dispersion and drying: The polypropylene film precursor and base film move to the electrostatic finishing section. After the insulating spherical shells are charged on their surfaces, a repulsive force is formed between adjacent insulating spherical shells, causing the insulating spherical shells to disperse. The distance between adjacent insulating spherical shells is equal, so that the insulating spherical shells are evenly distributed on the surface of the polypropylene film precursor near the base film. Then, the polypropylene film precursor and base film move to the drying section. Under high temperature, the solvent of the mixed slurry evaporates, and the insulating spherical shells also liquefy under the action of high temperature. However, under the combined action of the surface tension of the insulating spherical shells and the liquid polypropylene film precursor, the insulating spherical shells will form an ellipsoid within the range of the spherical particles, so that the polypropylene film precursor is shaped as a whole. S7. Static elimination: When the polypropylene film precursor and the base film move out of the range of the static finishing section, the polypropylene film precursor separates from the base film. The polypropylene film precursor is shaped to form the precursor of the polypropylene film, while the surface of the base film is adhered with an insulating spherical shell that has been re-cured by the liquid. The polypropylene film precursor and the base film are wound up separately. S8. Reprocessing: The precursor of the polypropylene film is reprocessed. The reprocessing steps include, but are not limited to, punching, lamination and sintering to obtain the polypropylene film. During the production process, the pellets can be evenly distributed on the surface of the polypropylene film precursor near the base film, thus increasing the antistatic effect.

[0006] Furthermore, a production equipment for antistatic polypropylene film includes a base frame, on which a base film is placed. Driven rollers and guide rollers one and two, and take-up roller one are fixedly connected to both ends of the base frame, respectively. The feeding section, settling section, electrostatic imparting section, electrostatic finishing section, and drying section are all located on the upper side of the base film. One end of the base film is fixedly connected to the driven roller, and the other end of the base film passes through guide roller one, feeding section, settling section, electrostatic imparting section, electrostatic finishing section, drying section, and guide roller two in sequence before being fixedly connected to take-up roller one. The direction of movement of the base film on the base frame is from the feeding section to the drying section.

[0007] Furthermore, the feeding section includes a material box, on which a feeding funnel is fixedly connected. The material box and the feeding funnel are connected. A discharge port is excavated at the bottom of the material box near the settling section. A scraper matching the discharge port is fixedly connected to the side wall of the material box near the settling section for temporary storage and feeding of the mixed slurry.

[0008] Furthermore, an insulating shell is provided inside the electrostatic imparting section. The insulating shell is fixedly connected to the upper end of the base frame, and an electrostatic head is fixedly connected to the upper end of the insulating shell. The electrostatic head imparts static electricity to the lower surface of the polypropylene film precursor through the base film.

[0009] Furthermore, the drying section includes a matching drying box and an air duct. A pair of connecting parts are fixedly connected between the drying box and the air duct, and the drying box and the air duct are connected through a pair of connecting parts. Multiple drying lamps are fixedly connected to the inner wall of the top plate of the drying box. When the polypropylene film precursor and the base film move to the position of the drying section, the base film is dried, so that the mixed slurry is dissolved and evaporated and recycled.

[0010] Furthermore, an antistatic polypropylene film includes a polypropylene film precursor, which includes a film body and an antistatic layer that are matched with each other. The film body and the antistatic layer are fixedly connected. Multiple spheres are embedded in the antistatic layer. The multiple spheres are evenly distributed on the side of the antistatic layer away from the film body. Each sphere includes an organosilicon core. Multiple carboxylated carbon fibers are fixedly connected to the outer wall of the organosilicon core. The multiple carboxylated carbon fibers are interwoven to form a network structure. Multiple surface tension grooves that match the positions of the spheres are cut at the end of the antistatic layer away from the film body.

[0011] Optionally, multiple conductive fibers are embedded in the insulating film. These conductive fibers interweave to form a mesh structure within the insulating film, making the insulating film conductive as a whole. Furthermore, the potential is the same at different locations, which makes it less likely for excessive local static electricity to accumulate in the polypropylene film precursor during the electrostatic imparting process. This reduces the likelihood of wrinkles or other defects in the formed polypropylene film precursor.

[0012] Furthermore, the amount of static charge imparted by the electrostatic head is controllable. Operators can adjust the amount of static charge imparted by the electrostatic head according to actual needs, so that the static charge carried on the surface of the pellets is controllable, which is used to control the spacing between adjacent pellets and adjust the performance of the polypropylene film precursor.

[0013] Furthermore, a negative pressure fan matching its own structure is installed inside the connecting part. The negative pressure fan creates a negative pressure space inside the drying chamber, making it difficult for the evaporated solvent to diffuse and thus less likely to affect the working environment.

[0014] Furthermore, a pressure sensor is fixedly connected to the inner wall of the top plate of the drying oven to monitor the air pressure inside the drying oven in real time. When the air pressure inside the drying oven increases to the normal pressure environment, the power of the negative pressure fan is increased to keep the air pressure inside the drying oven low, so that the solvent is not easily diffused.

[0015] Compared to existing technologies, the advantages of this application are: This solution utilizes electrostatics to organize the position of the spheres within the antistatic layer, ensuring a relatively uniform distribution of the spheres on the surface of the antistatic layer away from the main film body. This enhances the conductivity of the polypropylene film precursor. Exposed carboxylated carbon fibers absorb external moisture, forming a water film. When the external environment is relatively humid, the water films between adjacent carboxylated carbon fibers connect, creating conductive areas on the local surface of the polypropylene film precursor and reducing static electricity accumulation. Simultaneously, the conductive fibers ensure overall conductivity of the insulating film, with the potential being the same at different locations. This prevents excessive localized static electricity concentration during electrostatic application, reducing the likelihood of wrinkles and defects in the polypropylene film precursor. Furthermore, the controllable electrostatic application of the electrostatic head allows for controllable static charge on the sphere surface, enabling control over the spacing between adjacent spheres and adjusting the performance of the polypropylene film precursor. Finally, maintaining a low-pressure environment inside the drying oven prevents the evaporated solvent from spreading and negatively impacting the working environment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the fabrication of the antistatic polypropylene film of this application. Figure 2 This is a front sectional view of the main structure of the antistatic polypropylene film forming apparatus of this application. Figure 3 This is a partial structural diagram of the feeding section of the antistatic polypropylene film forming apparatus of this application; Figure 4 This is a partial structural schematic diagram of the electrostatic imparting part of the antistatic polypropylene film forming apparatus of this application. Figure 5 This is a partial structural schematic diagram of the drying section of the antistatic polypropylene film forming apparatus of this application. Figure 6 This is a schematic diagram of the structure of the antistatic polypropylene film product of this application; Figure 7 This is a schematic diagram of the antistatic masterbatch sedimentation process during the production of the antistatic polypropylene film of this application; Figure 8 This is a magnified view of a local structure at the interface between the antistatic polypropylene film and the base film during the production process. Figure 9 for Figure 8 A schematic diagram of the structural changes at point A during the drying process; Figure 10 This is a partial structural diagram of the antistatic polypropylene film of this application after production is completed; Figure 11 This is a schematic diagram of the structure of the antistatic masterbatch; Figure 12 This is a schematic diagram of a partial cross-sectional structure of the base membrane; Figure 13 This is a flowchart of the main process for preparing antistatic polypropylene film.

[0017] Explanation of the labels in the diagram: 1. Polypropylene film precursor, 101 Film body, 102 Antistatic layer, 103 Surface tension groove, 2 Base film, 201 Insulating film, 202 Conductive fiber, 3 Basic frame, 4 Driven roller, 5 Guide roller one, 6 Feeding section, 601 Material box, 602 Feeding funnel, 603 Scraper, 7 Settling section, 8 Static imparting section, 801 Insulating shell, 802 Static head, 9 Static finishing section, 10 Drying section, 1001 Drying oven, 1002 Air duct, 1003 Connecting section, 1004 Drying lamp, 1005 Negative pressure fan, 1006 Pressure sensor, 11 Guide roller two, 12 Take-up roller one, 13 Take-up roller two, 14 Spherical pellets, 1401 Organosilicon core, 1402 Carboxylated carbon fiber, 1403 Insulating shell. Detailed Implementation

[0018] The embodiments will be described clearly and completely with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0019] Example 1:

[0020] This invention provides a method for preparing an antistatic polypropylene film. Please refer to [link / reference]. Figure 1-2 and Figure 13 It mainly includes the following steps: S1. Preparation of antistatic masterbatch, wherein the antistatic masterbatch includes spheres 14, which include an organosilicon core 1401, carboxylated carbon fiber 1402, and an insulating shell 1403. The surfaces of the organosilicon core 1401 and the carboxylated carbon fiber 1402 are carboxylated, and then esterified grafting is performed to graft the carboxylated carbon fiber 1402 onto the surface of the carboxylated carbon fiber 1402 to obtain an organosilicon microsphere-g-carbon fiber structure. Then, the organosilicon microsphere-g-carbon fiber structure is put into the slurry of the insulating shell 1403, so that the slurry of the insulating shell 1403 is impregnated into the gaps of the carboxylated carbon fiber 1402. Then, the organosilicon microsphere-g-carbon fiber structure is taken out and dried to constant weight to obtain the finished spheres 14. S2. Preparation of polypropylene slurry: Polypropylene is dissolved using a solvent and a dispersant is added. The pellets 14 obtained in step S1 are then added to the liquid polypropylene to form a slurry. The slurry is then homogenized to ensure that the pellets 14 are evenly dispersed in the polypropylene slurry, thus obtaining a mixed slurry. S3. Polypropylene film formation: The polypropylene slurry obtained in step S2 is fed into the film forming equipment for production. The film forming equipment includes a base film 2, a feeding section 6, a settling section 7, an electrostatic imparting section 8, an electrostatic finishing section 9, and a drying section 10. The mixed slurry obtained in step S2 is fed into the feeding section 6 to form a polypropylene film precursor 1 on the upper surface of the base film 2. S4. Anti-static masterbatch sedimentation: When the polypropylene film precursor 1 and the base film 2 move into the sedimentation section 7, the spherical particles 14 in the polypropylene film precursor 1 will sink to the interface between the polypropylene film precursor 1 and the base film 2 because the density of the spherical particles 14 is greater than that of polypropylene. S5. Electrostatic application: When the polypropylene film precursor 1 and the base film 2 move to the range of the electrostatic application section 8, electrostatics are applied to the end of the polypropylene film precursor 1 near the base film 2, so that the end of the polypropylene film precursor 1 near the base film 2 and the outer surface of the insulating spherical shell 1403 are in a charged state. S6. Dispersion and drying: The polypropylene film precursor 1 and the base film 2 move to the area of ​​the electrostatic finishing section 9. After the surface of the insulating spherical shell 1403 is charged, a repulsive force is formed between two adjacent insulating spherical shells 1403, causing the insulating spherical shells 1403 to disperse. The distance between two adjacent insulating spherical shells 1403 is approximately equal, so that the insulating spherical shells 1403 are evenly distributed on the surface of the polypropylene film precursor 1 near the end of the base film 2. Then, the polypropylene film precursor 1 and the base film 2 move to the area of ​​the drying section 10. Under high temperature, the solvent of the mixed slurry evaporates. At the same time, the insulating spherical shells 1403 will also liquefy under the action of high temperature. However, under the combined action of the surface tension of the insulating spherical shells 1403 and the liquid polypropylene film precursor 1, the insulating spherical shells 1403 will form an ellipsoid within the area where the spherical particles 14 are located, so that the polypropylene film precursor 1 is shaped as a whole. S7. Static elimination: When the polypropylene film precursor 1 and the base film 2 move out of the range of the static finishing section 9, the polypropylene film precursor 1 and the base film 2 separate. The polypropylene film precursor 1 is shaped to form the precursor of the polypropylene film, while the surface of the base film 2 is adhered with an insulating spherical shell 1403 that has been re-cured by the liquid. The polypropylene film precursor 1 and the base film 2 are wound up separately. S8. Reprocessing: The precursor of the polypropylene film is reprocessed. The reprocessing steps include, but are not limited to, punching, lamination and sintering to obtain the polypropylene film.

[0021] For an antistatic polypropylene film production equipment, please refer to [link / reference]. Figure 1-5 The system includes a base frame 3, on the upper side of which a base film 2 is placed. Driven roller 4, guide roller 5, guide roller 11, and take-up roller 12 are fixedly connected to both ends of the base frame 3, respectively. Feeding section 6, settling section 7, electrostatic imparting section 8, electrostatic finishing section 9, and drying section 10 are all located on the upper side of the base film 2. One end of the base film 2 is fixedly connected to the driven roller 4, and the other end of the base film 2 passes through the guide roller 5, feeding section 6, settling section 7, electrostatic imparting section 8, electrostatic finishing section 9, drying section 10, and guide roller 11 in sequence before being fixedly connected to the take-up roller 12. The direction of movement of the base film 2 on the base frame 3 is from the feeding section 6 to the drying section 10.

[0022] It is worth noting that the basic frame 3 and its auxiliary structures in this application are all made of insulating materials and are regularly subjected to static electricity removal. During the static electricity removal process, the antistatic polypropylene film production equipment is idled to reduce the production of defective parts. At the same time, the antistatic polypropylene film production equipment is equipped with a control terminal, and the staff can control the specific working status of each structure of the antistatic polypropylene film production equipment through the control terminal. The installation method and specific control method of the control terminal are well known to those skilled in the art, so they are not disclosed in detail in this application. Those skilled in the art can make reasonable settings based on the existing technology.

[0023] In addition, some structures of the production equipment for the antistatic polypropylene film of this application require an auxiliary frame for support and fixation. This is a well-known technology to those skilled in the art, and therefore is not disclosed in detail in this application.

[0024] The feeding section 6 includes a material box 601, on which a feeding funnel 602 is fixedly connected. The material box 601 and the feeding funnel 602 are connected. A discharge port is cut at the bottom of the material box 601 near the settling section 7. A scraper 603 matching the discharge port is fixedly connected to the side wall of the material box 601 near the settling section 7 for temporary storage and feeding of the mixed slurry. An insulating shell 801 is provided inside the electrostatic charging section 8. The insulating shell 801 is fixedly connected to the upper end of the base frame 3. An electrostatic head 802 is fixedly connected to the upper end of the insulating shell 801. The electrostatic head 802 transmits electricity through the base frame 3. The membrane 2 imparts static electricity to the lower surface of the polypropylene film precursor 1. The drying section 10 includes a drying chamber 1001 and an air duct 1002 that are matched with each other. A pair of connecting parts 1003 are fixedly connected between the drying chamber 1001 and the air duct 1002. The drying chamber 1001 and the air duct 1002 are connected through the pair of connecting parts 1003. Multiple drying lamps 1004 are fixedly connected to the inner wall of the top plate of the drying chamber 1001. When the polypropylene film precursor 1 and the base film 2 move to the position of the drying section 10, the base film 2 is dried, so that the mixed slurry is dissolved and evaporated and recycled.

[0025] An antistatic polypropylene film, please refer to Figure 1 , Figure 6 and Figure 10-11 The device includes a polypropylene film precursor 1, which includes a film body 101 and an antistatic layer 102 that are matched with each other. The film body 101 and the antistatic layer 102 are fixedly connected. The antistatic layer 102 is embedded with a plurality of spheres 14. The plurality of spheres 14 are evenly distributed on the side of the antistatic layer 102 away from the film body 101. The spheres 14 include an organosilicon core 1401. The outer wall of the organosilicon core 1401 is fixedly connected with a plurality of carboxylated carbon fibers 1402. The plurality of carboxylated carbon fibers 1402 are interwoven to form a mesh structure. The end of the antistatic layer 102 away from the film body 101 is chiseled with a plurality of surface tension grooves 103 that match the positions of the spheres 14.

[0026] Please see Figure 7-10Before being introduced into the feeding section 6, the mixed slurry is homogenized, so the pellets 14 are evenly distributed within the mixed slurry. After the mixed slurry is extruded to form the polypropylene film precursor 1, the pellets 14 are also temporarily evenly distributed. Then, they naturally settle at the settling section 7, with all the pellets 14 falling to the interface between the polypropylene film precursor 1 and the base film 2. Afterward, the base film 2 moves to the location of the electrostatic imparting section 8. The electrostatic head 802 imparts static electricity to the end of the polypropylene film precursor 1 near the base film 2 and to the pellets 14. When the polypropylene film precursor 1 and the base film 2 move into the electrostatic finishing section 9, adjacent pellets 14 repel each other due to static electricity and maintain a stable relative distance, allowing the pellets 14 to be evenly distributed on the surface of the end of the polypropylene film precursor 1 near the base film 2. They then enter the drying section 10, where the high temperature causes the polypropylene film precursor 1 to... The solvent in the propylene film precursor 1 evaporates and solidifies, while the insulating spherical shell 1403, which is not resistant to high temperatures, liquefies. Under the combined action of the surface tension of the insulating spherical shell 1403 and the liquid polypropylene film precursor 1, the insulating spherical shell 1403 forms an ellipsoid within the area where the spherical particles 14 are located, thus solidifying the polypropylene film precursor 1 as a whole. Afterward, the polypropylene film precursor 1 separates from the base film 2, leaving multiple regular surface tension grooves 103 and partially exposed carboxylated carbon fibers 1402 on the surface of the antistatic layer 102 at the end away from the film body 101. The exposed carboxylated carbon fibers 1402 absorb external moisture and form a water film. The water film between two adjacent carboxylated carbon fibers 1402 will connect together when the external environment is relatively humid, forming a conductive area on the local surface of the polypropylene film precursor 1, reducing static electricity accumulation.

[0027] Specifically, in this application, the polypropylene film precursor 1 has inner and outer ends. The side where the film body 101 is located is the inner end, that is, during the packaging process, the film body 101 is the end that is close to the packaged item. This is also the case when the polypropylene film precursor 1 is used for other purposes. The antistatic layer 102 is the antistatic end, which is exposed to the outside. At the same time, the composition of the film body 101 and the antistatic layer 102 is roughly the same. Only the antistatic layer 102 contains spherical particles 14, which have the function of antistatic. Based on the function, there is no obvious separation between the film body 101 and the antistatic layer 102.

[0028] Example 2:

[0029] This invention provides a production equipment for antistatic polypropylene film. Please refer to [link / reference]. Figure 12Multiple conductive fibers 202 are embedded in the insulating film 201. The multiple conductive fibers 202 interweave with each other to form a mesh structure in the insulating film 201, so that the insulating film 201 can conduct electricity as a whole, and the potential is the same at different positions. This makes it less likely for excessive local static electricity to accumulate in the polypropylene film precursor 1 during the electrostatic imparting process, and less likely to cause wrinkles or other defects in the molding of the polypropylene film precursor 1.

[0030] Please see Figure 4 The amount of static charge imparted by the electrostatic head 802 is controllable. The operator can adjust the amount of static charge imparted by the electrostatic head 802 according to actual needs, so that the static charge carried on the surface of the pellet 14 is controllable, which is used to control the spacing between adjacent pellets 14 and adjust the performance of the polypropylene film precursor 1.

[0031] Please see Figure 5 The connecting part 1003 is equipped with a matching negative pressure fan 1005. The negative pressure fan 1005 creates a negative pressure space in the drying oven 1001, making it difficult for the evaporated solvent to diffuse and thus less likely to affect the working environment. A pressure sensor 1006 is fixedly connected to the inner wall of the top plate of the drying oven 1001 to monitor the air pressure in the drying oven 1001 in real time. When the air pressure in the drying oven 1001 increases to the normal pressure environment, the power of the negative pressure fan 1005 is increased to keep the air pressure in the drying oven 1001 low, making it difficult for the solvent to diffuse.

[0032] In Embodiment 1 of this scheme, electrostatics are used to arrange the positions of the spherical particles 14 within the antistatic layer 102, so that the spherical particles 14 can be relatively uniformly distributed on the surface of the antistatic layer 102 away from the film body 101, thereby enhancing the conductivity of the polypropylene film precursor 1. The high temperature in the drying section 10 causes the solvent in the polypropylene film precursor 1 to evaporate and solidify, while the insulating shell 1403, which is not resistant to high temperatures, liquefies. Under the combined action of the surface tension of the insulating shell 1403 and the liquid polypropylene film precursor 1, the insulating shell 1403 will be located where the spherical particles 14 are located. An ellipsoidal shape is formed within the range, which makes the polypropylene film precursor 1 integrally shaped. Then, the polypropylene film precursor 1 separates from the base film 2, leaving multiple regular surface tension grooves 103 and partially exposed carboxylated carbon fibers 1402 on the surface of the antistatic layer 102 away from the film body 101. The exposed carboxylated carbon fibers 1402 absorb external moisture and form a water film. The water film between two adjacent carboxylated carbon fibers 1402 will connect together when the external environment is relatively humid, forming a conductive area on the local surface of the polypropylene film precursor 1, reducing static electricity accumulation.

[0033] While the various structural formulas in Example 2 represent functional improvements over the structure in Example 1, they significantly increase the practical cost of the structure in Example 1. Technical personnel must make reasonable selections based on actual production needs. The conductive fiber 202 enables the insulating film 201 to conduct electricity as a whole, with the same potential at different locations. This prevents excessive localized static electricity concentration in the polypropylene film precursor 1 during electrostatic imparting, reducing the likelihood of wrinkles and defects. Furthermore, setting the electrostatic head 802 to controllable electrostatic imparting allows for controllable static charge on the surface of the pellets 14, controlling the spacing between adjacent pellets 14 and adjusting the performance of the polypropylene film precursor 1. Finally, maintaining a low-pressure environment inside the drying oven 1001 prevents the evaporated solvent from easily diffusing and impacting the working environment.

[0034] The above description is only the best implementation method adopted in this application in combination with current practical needs, but the scope of protection of this application is not limited thereto.

Claims

1. A method for preparing an antistatic polypropylene film, characterized in that, The main steps include: S1. Preparation of antistatic masterbatch, wherein the antistatic masterbatch includes spheres (14), the spheres (14) include organosilicon core (1401), carboxylated carbon fiber (1402) and insulating shell (1403). The surfaces of organosilicon core (1401) and carboxylated carbon fiber (1402) are carboxylated respectively, and then esterification grafting is performed. The carboxylated carboxylated carbon fiber (1402) is grafted onto the surface of carboxylated carbon fiber (1402) to obtain organosilicon microsphere-g-carbon fiber structure. Then the organosilicon microsphere-g-carbon fiber structure is put into the slurry of insulating shell (1403) so that the slurry of insulating shell (1403) is impregnated into the gaps of carboxylated carbon fiber (1402). Then the organosilicon microsphere-g-carbon fiber structure is taken out and dried to constant weight to obtain the finished spheres (14). S2. Polypropylene slurry preparation: dissolve polypropylene with solvent and add dispersant. Then add the pellets (14) obtained in step S1 into liquid polypropylene to form slurry. Homogenize the slurry so that the pellets (14) are evenly dispersed in the polypropylene slurry to obtain mixed slurry. S3. Polypropylene film formation: The polypropylene slurry obtained in step S2 is fed into the film forming equipment for production. The film forming equipment includes a base film (2), a feeding section (6), a settling section (7), an electrostatic imparting section (8), an electrostatic finishing section (9), and a drying section (10). The mixed slurry obtained in step S2 is fed into the feeding section (6) to form a polypropylene film precursor (1) on the upper surface of the base film (2). S4. Anti-static masterbatch sedimentation: When the polypropylene film precursor (1) and base film (2) move into the sedimentation section (7), the spheres (14) in the polypropylene film precursor (1) will sink to the interface between the polypropylene film precursor (1) and the base film (2) because the density of the spheres (14) in the polypropylene film precursor (1) is greater than that of polypropylene. S5. Electrostatic imparting: When the polypropylene film precursor (1) and the base film (2) move to the range of the electrostatic imparting part (8), electrostatics are imparted to the end of the polypropylene film precursor (1) near the base film (2), so that the end of the polypropylene film precursor (1) near the base film (2) and the outer surface of the insulating spherical shell (1403) are in a charged state. S6. Dispersion and drying: The polypropylene film precursor (1) and the base film (2) move to the electrostatic finishing section (9). After the surface of the insulating spherical shell (1403) is charged, a repulsive force is formed between two adjacent insulating spherical shells (1403), causing the insulating spherical shells (1403) to disperse. The distance between two adjacent insulating spherical shells (1403) is equal, so that the insulating spherical shells (1403) are evenly distributed on the surface of the polypropylene film precursor (1) near the end of the base film (2). Then the polypropylene film precursor (1) and the base film (2) move to the drying section (10). Under high temperature, the solvent of the mixed slurry evaporates. At the same time, the insulating spherical shells (1403) will also liquefy under the action of high temperature. However, under the combined action of the surface tension of the insulating spherical shells (1403) and the polypropylene film precursor (1) in the liquid, the insulating spherical shells (1403) will form an ellipsoid within the range of the spherical particles (14), so that the polypropylene film precursor (1) is shaped as a whole. S7. Static electricity elimination: When the polypropylene film precursor (1) and the base film (2) move out of the range of the static electricity finishing section (9), the polypropylene film precursor (1) separates from the base film (2), the polypropylene film precursor (1) is shaped to form the precursor of the polypropylene film, while the surface of the base film (2) is adhered with an insulating spherical shell (1403) that has been re-cured by the liquid, and the polypropylene film precursor (1) and the base film (2) are wound up respectively. S8. Reprocessing: The precursor of the polypropylene film is reprocessed. The reprocessing steps include punching, lamination and sintering to obtain the polypropylene film.

2. An apparatus for preparing an antistatic polypropylene film, applied to the method for preparing the antistatic polypropylene film according to claim 1, characterized in that, The system includes a base frame (3), on which a base film (2) is placed. Driven roller (4) and guide roller 1 (5) and guide roller 2 (11) and take-up roller 1 (12) are fixedly connected to both ends of the base frame (3). Feeding section (6), settling section (7), electrostatic imparting section (8), electrostatic finishing section (9) and drying section (10) are all located on the upper side of the base film (2). One end of the base film (2) is fixedly connected to the driven roller (4). The other end of the base film (2) passes through guide roller 1 (5), feeding section (6), settling section (7), electrostatic imparting section (8), electrostatic finishing section (9), drying section (10) and guide roller 2 (11) in sequence and is fixedly connected to take-up roller 1 (12). The movement direction of the base film (2) on the base frame (3) is from feeding section (6) to drying section (10).

3. The device for producing an antistatic polypropylene film according to claim 2, characterized in that, The feeding section (6) includes a material box (601), a feeding funnel (602) is fixedly connected to the material box (601), the material box (601) and the feeding funnel (602) are connected, a discharge port is chiseled at the bottom of the material box (601) near the settling section (7), and a scraper (603) matching the discharge port is fixedly connected to the side wall of the material box (601) near the settling section (7).

4. The equipment for producing an antistatic polypropylene film according to claim 2, characterized in that, An insulating shell (801) is provided inside the electrostatic imparting part (8). The insulating shell (801) is fixedly connected to the upper end of the base frame (3). An electrostatic head (802) is fixedly connected to the upper end of the insulating shell (801).

5. The apparatus for producing an antistatic polypropylene film according to claim 2, characterized in that, The drying unit (10) includes a drying box (1001) and an air duct (1002) that are matched with each other. A pair of connecting parts (1003) are fixedly connected between the drying box (1001) and the air duct (1002). The drying box (1001) and the air duct (1002) are connected through a pair of connecting parts (1003). A plurality of drying lamps (1004) are fixedly connected to the inner wall of the top plate of the drying box (1001).

6. The apparatus for producing an antistatic polypropylene film according to claim 2, characterized in that, The base film (2) includes an insulating film body (201), in which a plurality of conductive fibers (202) are embedded, and the plurality of conductive fibers (202) interweave with each other to form a mesh structure within the insulating film body (201).

7. The apparatus for producing an antistatic polypropylene film according to claim 4, characterized in that, The amount of static charge imparted by the electrostatic head (802) is controllable, and the operator can adjust the amount of static charge imparted by the electrostatic head (802) according to actual needs.

8. The apparatus for producing an antistatic polypropylene film according to claim 5, characterized in that, A negative pressure fan (1005) matching itself is installed inside the connecting part (1003).

9. The apparatus for producing an antistatic polypropylene film according to claim 5, characterized in that, A pressure sensor (1006) is fixedly connected to the inner wall of the top plate of the drying oven (1001) for real-time monitoring of the pressure inside the drying oven (1001).

10. An antistatic polypropylene film, obtained by the preparation method of the antistatic polypropylene film according to claim 1, characterized in that, The material includes a polypropylene film precursor (1), which includes a film body (101) and an antistatic layer (102) that are matched with each other. The film body (101) and the antistatic layer (102) are fixedly connected. The antistatic layer (102) is embedded with a plurality of spheres (14). The plurality of spheres (14) are evenly distributed on the side of the antistatic layer (102) away from the film body (101). The spheres (14) include an organosilicon core (1401). The outer wall of the organosilicon core (1401) is fixedly connected with a plurality of carboxylated carbon fibers (1402). The plurality of carboxylated carbon fibers (1402) are interwoven to form a mesh structure. The end of the antistatic layer (102) away from the film body (101) is chiseled with a plurality of surface tension grooves (103) that match the position of the spheres (14).

Images