A method for producing an explosion-proof polyester needle felt

Abstract

The application discloses a production method of an explosion-proof polyester needled felt, and aims to provide a production method which has good anti-static effect and explosion-proof effect, is simple in preparation, and is high in forming integration degree, and the technical scheme is as follows: the anti-static micro-porous film and the mixed fiber felt mixed with the anti-static fiber are adopted, and then steam hot pressing is performed, so that the anti-static effect of the mixed fiber felt is greatly improved, and the overall explosion-proof effect is improved; the anti-static micro-porous film is coated, and the anti-static fiber is mixed, so that the double anti-static fiber is formed, the practicality is high, the structure is simple, and the application is suitable for the technical field of needled felt preparation.

Description

Technical Field

[0001] This invention relates to the field of needle-punched felt preparation technology, and more specifically, to a method for producing explosion-proof polyester needle-punched felt. Background Technology

[0002] Industrial needle-punched felt is a dust removal device made by sewing industrial filter cloth. Industrial filter cloth is a filter medium woven from natural and synthetic fibers, mainly used for solid-liquid separation and industrial dust removal. Bag dust collectors are a type of high-efficiency dry dust collector. They rely on filter bags made of fiber filter material, and more importantly, they purify the gas through the dust layer formed on the surface of the filter bags. For almost all dust in general industry, its dust removal efficiency can reach more than 99%. The core component of belt dust collectors is needle-punched felt.

[0003] The filter cloth materials of industrial needle-punched felt used in belt dust collectors are gradually being changed to organic and inorganic man-made fiber fabrics or their blends, such as nylon, orlon, polyester, and glass fiber. In actual use, especially in the dust removal process of metal powders such as magnesium powder, the needle-punched felt is prone to explosion due to the large static electricity, which can lead to fire and reduce the safety factor. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a production method that produces needle-punched felt with good antistatic and explosion-proof effects, and which is simple to prepare and has a high degree of integrated molding.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for producing explosion-proof polyester needle-punched felt, comprising the following steps: S1, preparing an antistatic microporous membrane: adding antistatic material to polytetrafluoroethylene resin raw material, mixing the above material evenly, introducing it into an extruder, and obtaining an antistatic microporous membrane with a thickness of 15-30μm, a porosity of 50%-85%, and a pore size distribution of 0.3-5μm by extrusion, calendering, stretching, and heat setting, wherein the obtained antistatic microporous membrane is used as a preparatory material, wherein the extrusion temperature is between 200℃-300℃, the calendering pressure is between 200N-500N, the biaxial stretching is used to obtain a thickness of 5-50μm, and the heat setting temperature is between 150℃-180℃;

[0006] S2. Preparation of mixed fiber felt: Polyester fiber and antistatic fiber are mixed evenly at a weight ratio of 40-60:20-30 to obtain mixed fiber; the mixed fiber is fed into a carding machine by a cotton feeder to form a mixed fiber web; the mixed fiber web is conveyed to a cotton spreading machine, and multiple layers of mixed limiting web are laid to form mixed fiber felt; the mixed fiber felt is needle-punched and reinforced on a needle punching machine at a needle punching speed of 500-600 rpm to obtain a polyester needle-punched felt semi-finished product;

[0007] S3. The polyester needle-punched felt semi-finished product after needle-punching reinforcement in step S2 is placed in a hot press mold and hot-pressed under vacuum. The windward side of the polyester needle-punched felt semi-finished product is the hot-pressed coating side.

[0008] S4. Place the semi-finished polyester needle-punched felt after step S3 into a cooling fixture and cool and shape it at room temperature for 60 to 70 seconds.

[0009] S5. Cut the polyester needle-punched felt semi-finished product cooled in step S4 into the required external dimensions to obtain the finished polyester needle-punched felt product.

[0010] The present invention is further configured such that: the specific method of hot pressing and film coating in step S3 is as follows: S31, the antistatic microporous film obtained in step S1 is coated on the polyester needle-punched felt semi-finished product;

[0011] S32. Vacuum the upper mold of the hot press mold for 10-20 seconds at a pressure of 0.01-0.02 MPa, and introduce high-temperature steam while vacuuming.

[0012] S33. Maintain the vacuum level and continue to introduce high-temperature steam for heating and molding. The high-temperature steam pressure is 2.5-3MPa, the inflation time is between 3min and 5min, the high-temperature steam temperature is 150-300℃, the mold pressing pressure is between 300N and 800N, and the molding time is 20-60 seconds until hot pressing is completed.

[0013] S34. After hot pressing is completed, the material that has been coated is pulled by the traction equipment, the high temperature steam in the upper mold is vented, and then the subsequent material that has not been hot pressed is hot pressed and coated.

[0014] The present invention is further configured such that: the hot press mold includes a steam channel and a flow rate control mechanism disposed within the steam channel; the flow rate control mechanism includes an adjustment channel disposed within the steam channel, an regulator disposed within the adjustment channel, and a lifting device for driving the regulator to rise and fall and adjusting the air output of the adjustment channel; the regulator is configured such that when it descends to the air output channel of the adjustment channel, the regulator and the inner wall of the air output channel form an annular flow channel; when it is disengaged from the air output channel by the lifting device, the air output channel restores its original air output.

[0015] The present invention is further configured such that: a membrane cutting structure is provided between the upper and lower molds of the hot pressing mold, the membrane cutting structure including a side cutting groove structure provided on the lower mold and a side cutting protrusion provided on the upper mold and adapted to the side cutting groove structure, a shearing structure is formed between the side cutting groove structure and the side cutting protrusion, the shearing structure is used to form a timely shearing action with the lower mold after the upper mold is pressed down, and to shear and cut the excess part of the antistatic microporous membrane.

[0016] The present invention is further configured such that: a flow regulation structure is provided between the regulator and the air outlet channel, the flow regulation structure includes a stepped structure and several stepped structures disposed on the regulator, the outer diameter difference between two adjacent stepped structures is between 2cm and 5cm, and the difference between two adjacent stepped structures is the same, and a primary channel, a secondary channel and a tertiary channel with air volume decreasing from large to small are formed between the stepped structure and the air outlet channel.

[0017] The present invention is further configured such that: the flow rate control mechanism also includes a control system, which includes a pressure monitor for real-time monitoring of the upper mold steam pressure, a flow rate monitor installed in the outlet channel, an electromagnetic on / off valve installed in the steam channel, and a controller for controlling the start and stop of the lifting device and the on / off of the electromagnetic on / off valve. The controller includes a receiving unit electrically connected to the pressure detector and the flow rate monitor and for receiving electrical signals from both monitors, a comparison unit for setting a standard and warning value for the upper mold steam pressure and comparing it with the monitored value, and a control unit for controlling the on / off of the electromagnetic on / off valve and the start and stop of the lifting device. The control method of the flow rate control mechanism in the steam channel specifically includes the following steps: S330, setting the warning pressure value of the upper mold steam pressure to P0, setting the standard value of the upper mold steam pressure to P, real-time monitoring the upper mold steam pressure value to Pt, setting the flow rate warning value of the outlet channel to S, and then introducing steam;

[0018] S331. During the first time period, P1 and PO are compared by the comparison unit. If P1 is less than P0, steam continues to flow. Otherwise, if P1 is greater than P0, the regulator needs to be downgraded by the upgrade device to reduce the steam flow and adjust to the first-level channel.

[0019] S332. During the second time period, the steam pressure value of the upper mold is monitored in real time as P2. The difference between P2 and P is △. If the value of △ is within the reasonable range of pressure control, the gas is continued to be supplied through the first-level channel. If the value of △ is outside the above range, the regulator needs to be downgraded through the upgrade device to reduce the steam flow and adjust to the second-level channel for gas supply within the time ts until the value of P is reached.

[0020] S333. During the above time period, the flow velocity in the outlet channel is monitored in real time as S1. If S1 is greater than the value of S, it is determined that the airflow disturbance is large and the regulator needs to be downgraded through the upgrade device to reduce the steam flow and adjust to the third channel. The adjustment time is tp. Otherwise, the ventilation is carried out according to the current required ventilation volume.

[0021] S334. During the tp time period, monitor the flow velocity Sp in the outlet channel in real time. If Sp is less than the S value, it is determined that the airflow disturbance is small, and continue to adjust to the current required ventilation volume; otherwise, continue to ventilate through the three-stage channel.

[0022] An explosion-proof polyester needle-punched felt produced by the above-mentioned production method of explosion-proof polyester needle-punched felt, wherein the polyester needle-punched felt has a 4-layer structure, and the 3 layers of the polyester needle-punched felt are all made by mixing polyester fibers and antistatic fibers, combing and mixing them into a web, and then needle-punching the three-layer mixed fiber web into a felt through a needle-punching process.

[0023] Polyester fiber and antistatic fiber are mixed evenly in a weight ratio of 40-60:20-30, and the length of the antistatic fiber is between 2-3 cm. The antistatic fiber is one or more of metal fiber or organic polymer-based metal complex antistatic fiber.

[0024] The antistatic microporous membrane and the mixed fiber felt are coated on one side by steam hot pressing to obtain a coated filter material. The coated surface of the antistatic microporous membrane is the windward side of the polyester needle-punched felt. The antistatic material in the antistatic microporous membrane contains at least an antistatic organic polymer.

[0025] By adopting the above technical solution, the following benefits are achieved: 1. By using an antistatic microporous membrane and a mixed fiber felt containing antistatic fibers, and then steam hot pressing molding, the antistatic effect of the mixed fiber felt is greatly increased, thereby improving the overall explosion-proof effect. The antistatic microporous membrane is coated and the antistatic fibers are mixed to form a double antistatic fiber, which is highly practical and has a simple structure.

[0026] 2. The use of a hot-pressing mold instead of a roller press is to form a coating on the antistatic microporous membrane through steam pressure and the pressure generated by the upper and lower molds themselves. The steam mold hot pressing method creates a dual pressure effect, which makes the contact area between the antistatic microporous membrane and the filter material larger and the stress more uniform, resulting in a better overall coating effect, strong practicality, and simple structure.

[0027] 3. Further, by setting the hot press mold to include a steam channel and a flow rate control mechanism set within the steam channel, the flow rate control mechanism includes an adjustment channel set within the steam channel, an regulator set within the adjustment channel, and a lifting device for driving the regulator to rise and fall and adjusting the air output of the adjustment channel. The regulator is configured such that when it descends to the air output channel of the adjustment channel, the regulator and the inner wall of the air output channel form an annular flow channel; when it is driven to disengage from the air output channel by the lifting device, the air output channel restores its original air volume. In order to better stabilize the steam pressure of the upper mold, the flow rate control mechanism adjusts the adjustment channel, the regulator, and the lifting device. The regulator adjusts the air volume in the adjustment channel to control the steam volume, ensuring the stability of the steam pressure, stabilizing the subsequent steam pressure reduction, keeping the lower mold pressure at the standard value, improving the overall film adhesion, and preventing damage to the antistatic microporous membrane.

[0028] 4. Furthermore, by providing a membrane cutting structure between the upper and lower molds of the hot press mold, the excess portion of the antistatic microporous membrane is cut off in real time, facilitating subsequent collection of filter material and reducing the impact of excess membrane edges on collection. This membrane cutting structure includes a side-cutting groove structure on the lower mold and a side-cutting protrusion on the upper mold that matches the side-cutting groove structure. A shearing structure is formed between the side-cutting groove structure and the side-cutting protrusion. This shearing structure is used to perform timely shearing with the lower mold after the upper mold is pressed down, cutting off excess material from the antistatic microporous membrane. The side-cutting groove structure and the side-cutting protrusion create a shearing effect between them. Because side-cutting and pressing are performed simultaneously, real-time removal of excess material after membrane coating is achieved, avoiding subsequent reprocessing. This design is highly practical and has a simple structure. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the coating structure of an embodiment of the production method of explosion-proof polyester needle-punched felt according to the present invention.

[0030] Figure 2 This is a cross-sectional view of a hot pressing mold according to an embodiment of the production method of explosion-proof polyester needle-punched felt of the present invention.

[0031] In the attached diagram, the following labels are used: 1. Hot press mold; 10. Steam channel; 2. Adjustment channel; 20. Regulator; 21. Lifting device; 201. Annular flow channel; 220. Side-cut groove structure; 221. Side-cut protrusion; 202. Step structure; 203. Primary channel; 204. Secondary channel; 205. Tertiary channel; 3. Controller; 30. Air pressure monitor; 31. Flow rate monitor; 32. Solenoid on / off valve. Detailed Implementation

[0032] Reference Figures 1 to 2 The present invention provides a further description of an embodiment of a production method for an explosion-proof polyester needle-punched felt.

[0033] For ease of explanation, spatial relative terms such as “up,” “down,” “left,” and “right” are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is inverted, an element described as being “down” of other elements or features would be positioned “up” of those other elements or features. Therefore, the exemplary term “down” can encompass both up and down orientations. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0034] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0035] A method for producing explosion-proof polyester needle-punched felt includes the following steps: S1. Preparing an antistatic microporous membrane: adding antistatic material to polytetrafluoroethylene resin raw material, mixing the above material evenly, and then feeding it into an extruder. The membrane is then obtained through extrusion, calendering, stretching, and heat setting to achieve a thickness of 15-30 μm, a porosity of 50%-85%, and a pore size distribution between 0.3-5 μm. The obtained antistatic microporous membrane is used as a preparatory material. The extrusion temperature is between 200℃ and 300℃, the calendering pressure is between 200N and 500N, the membrane is biaxially stretched to a thickness of 5-50 μm, and the heat setting temperature is between 150℃ and 180℃.

[0036] S2. Preparation of mixed fiber felt: Polyester fiber and antistatic fiber are mixed evenly at a weight ratio of 40-60:20-30 to obtain mixed fiber; the mixed fiber is fed into a carding machine by a cotton feeder to form a mixed fiber web; the mixed fiber web is conveyed to a cotton spreading machine, and multiple layers of mixed limiting web are laid to form mixed fiber felt; the mixed fiber felt is needle-punched and reinforced on a needle punching machine at a needle punching speed of 500-600 rpm to obtain a polyester needle-punched felt semi-finished product;

[0037] S3. The polyester needle-punched felt semi-finished product after needle-punching reinforcement in step S2 is placed in a hot press mold and hot-pressed under vacuum. The windward side of the polyester needle-punched felt semi-finished product is the hot-pressed coating side.

[0038] S4. Place the semi-finished polyester needle-punched felt after step S3 into a cooling fixture and cool and shape it at room temperature for 60 to 70 seconds.

[0039] S5. Cut the polyester needle-punched felt semi-finished product cooled in step S4 into the required external dimensions to obtain the finished polyester needle-punched felt product.

[0040] By employing an antistatic microporous membrane and a mixed fiber felt containing antistatic fibers, and then steam hot pressing, the antistatic effect of the mixed fiber felt is greatly increased, thereby improving the overall explosion-proof effect. The antistatic microporous membrane is coated and the antistatic fibers are mixed to form a double antistatic fiber, which is highly practical and simple in structure. Furthermore, by changing the steam mold hot pressing method to the roller pressing method, the overall coating stability is good, the temperature is easy to control, the coating area is large, and the overall coating pressure is more uniform. It is highly practical and simple in structure.

[0041] The present invention is further configured such that the hot-pressing coating method in step S3 is as follows: S31, the antistatic microporous membrane obtained in step S1 is coated on the polyester needle-punched felt semi-finished product.

[0042] S32. Vacuum the upper mold of the hot press mold for 10-20 seconds at a pressure of 0.01-0.02 MPa, and introduce high-temperature steam while vacuuming.

[0043] S33. Maintain the vacuum level and continue to introduce high-temperature steam for heating and molding. The high-temperature steam pressure is 2.5-3MPa, the inflation time is between 3min and 5min, the high-temperature steam temperature is 150-300℃, the mold pressing pressure is between 300N and 800N, and the molding time is 20-60 seconds until hot pressing is completed.

[0044] S34. After hot pressing is completed, the material that has been coated is pulled by the traction equipment, the high temperature steam in the upper mold is vented, and then the subsequent material that has not been hot pressed is hot pressed and coated.

[0045] The use of a hot-pressing mold instead of a roller press is to form a coating on the antistatic microporous membrane through steam pressure and the pressure generated by the upper and lower molds themselves. The steam mold hot pressing method creates a dual pressure effect, which makes the contact area between the antistatic microporous membrane and the filter material larger and the stress more uniform, resulting in a better overall coating effect, strong practicality, and simple structure.

[0046] The present invention is further configured such that the hot press mold 1 includes a steam channel 10 and a flow rate control mechanism disposed within the steam channel 10. The flow rate control mechanism includes an adjustment channel 2 disposed within the steam channel 10, a regulator 20 disposed within the adjustment channel 2, and a lifting device 21 for driving the regulator 20 to rise and fall and adjusting the air output of the adjustment channel 2. The regulator 20 is configured such that when it descends to the air output channel of the adjustment channel 2, the regulator 20 and the inner wall of the air output channel form an annular flow channel 201; when it is disengaged from the air output channel by the lifting device 21, the air output channel restores its original airflow. Furthermore, by configuring the hot press mold 1 to include a steam channel 10 and a flow rate control mechanism disposed within the steam channel 10, the flow rate control mechanism includes an adjustment channel 2 disposed within the steam channel 10, a regulator 20 disposed within the adjustment channel 2, and a lifting device 21 for driving the regulator 20 to rise and fall and adjusting the air output of the adjustment channel 2. The regulating channel 2 includes a regulator 20 and a lifting device 21 for driving the regulator 20 to rise and fall and adjusting the air output of the regulating channel 2. The regulator 20 is configured such that when it descends to the air output channel of the regulating channel 2, the regulator 20 and the inner wall of the air output channel form an annular flow channel 201. When it is driven away from the air output channel by the lifting device 21, the air output channel returns to its original air volume. In order to better stabilize the steam pressure of the upper mold, the regulating channel 2, the regulator 20 and the lifting device 21 are adjusted by the flow rate control mechanism. The regulator 20 adjusts the air output of the regulating channel 2 to control the steam volume, ensuring the stability of the steam pressure and the subsequent stable effect of the steam pressure. The lower mold pressure is at the standard value, which improves the overall film adhesion and prevents damage to the antistatic microporous membrane.

[0047] It should be noted that the steam hot pressing method used in this application, and the steam pressure controlled at the corresponding pressure value, is to improve the efficiency of hot pressing and coating, achieve the balance of steam pressure on the upper mold, and the consistency of the surface temperature of the upper mold.

[0048] The present invention is further configured such that a membrane cutting structure is provided between the upper and lower molds of the hot pressing mold 1. This membrane cutting structure includes a side cutting groove structure 220 disposed on the upper mold and a side cutting protrusion 221 disposed on the upper mold and adapted to the side cutting groove structure 220. A shearing structure is formed between the side cutting groove structure 220 and the side cutting protrusion 221. This shearing structure is used to perform timely shearing action with the lower mold after the upper mold is pressed down, cutting off excess material from the antistatic microporous membrane. Furthermore, by providing a membrane cutting structure between the upper and lower molds of the hot pressing mold 1, excess material from the antistatic microporous membrane is cut off in real time, facilitating subsequent collection of the filter material and reducing the impact of excess membrane edges on collection. Furthermore, by configuring the film cutting structure to include a side cutting groove structure 220 disposed on the lower mold and a side cutting protrusion 221 disposed on the upper mold and adapted to the side cutting groove structure 220, a shearing structure is formed between the side cutting groove structure 220 and the side cutting protrusion 221. This shearing structure is used to form a timely shearing action with the lower mold after the upper mold is pressed down, thereby shearing and cutting off the excess part of the antistatic microporous membrane. Through the configured side cutting groove structure 220 and the side cutting protrusion 221, a shearing action is formed between the side cutting groove structure 220 and the side cutting protrusion 221. Since the side cutting and pressing are carried out simultaneously, the real-time removal of the edge material after lamination can be increased, avoiding subsequent reprocessing. It is highly practical and has a simple structure.

[0049] The present invention is further configured such that a flow regulation structure is provided between the regulator 20 and the outlet channel. The flow regulation structure includes a plurality of stepped structures 202 disposed on the regulator 20. The difference in outer diameter between two adjacent stepped structures 202 is between 2cm and 5cm, and the difference between two adjacent stepped structures 202 is the same. The stepped structures 202 and the outlet channel form a primary channel 203, a secondary channel 204, and a tertiary channel 205 with the air flow rate decreasing from large to small. With the above-mentioned structural configuration, because the stepped structures 202 disposed on the regulator 20 form a primary channel 203, a secondary channel 204, and a tertiary channel 205 with the air flow rate decreasing from large to small between the regulator 20 and the outlet channel, the overall air flow rate becomes adjustable. This makes the system highly practical, simple in structure, and ensures that the stability of steam flow is increased.

[0050] The present invention is further configured such that the flow rate control mechanism also includes a control system, which includes a pressure monitor 30 for real-time monitoring of the upper mold steam pressure, a flow rate monitor 31 disposed in the outlet channel, an electromagnetic on / off valve 32 disposed on the steam channel 10, and a controller 3 for controlling the start and stop of the lifting device 21 and the on / off of the electromagnetic on / off valve 32. The controller 3 includes a receiving unit electrically connected to the pressure detector and the flow rate monitor 31 and for receiving electrical signals from both monitors, a comparison unit for setting a standard and warning value for the upper mold steam pressure and comparing it with the monitored value, and a control unit for controlling the on / off of the electromagnetic on / off valve 32 and the start and stop of the lifting device 21. The control method of the flow rate control mechanism in the steam channel 10 specifically includes the following steps: S330, setting the warning pressure value of the upper mold steam pressure to P0, setting the standard value of the upper mold steam pressure to P, real-time monitoring the upper mold steam pressure value to Pt, setting the flow rate warning value of the outlet channel to S, and then introducing steam;

[0051] S331. During the first time period, P1 and P0 are compared by the comparison unit. If P1 is less than P0, steam continues to flow. Otherwise, if P1 is greater than P0, the regulator 20 needs to be downgraded by the upgrade device to reduce the steam flow and adjust to the first-level channel 203.

[0052] S332. During the second time period, the steam pressure of the upper mold is monitored in real time as P2. The difference between P2 and P is Δ. If the value of Δ is within the reasonable range of pressure control, the steam continues to be supplied through the first-level channel 203. If the value of Δ is outside the above range, the regulator 20 needs to be lowered through the upgrade device to reduce the steam flow and adjust to the second-level channel 204 to supply steam for ts time until the value of P is reached.

[0053] S333. During the above time period, the flow velocity in the outlet channel is monitored in real time as S1. If S1 is greater than S, it is determined that the airflow disturbance is large and the regulator 20 needs to be lowered through the upgrade device to reduce the steam flow and adjust to the third channel 205. The adjustment time is tp. Otherwise, the ventilation is performed according to the current required ventilation volume.

[0054] S334. During the tp time period, monitor the flow velocity Sp in the outlet channel in real time. If Sp is less than the S value, it is determined that the airflow disturbance is small, and continue to adjust to the current required ventilation volume; otherwise, continue to ventilate through the third-level channel 205.

[0055] By using the above method, a pressure monitor 30 is installed in the steam cavity of the upper mold, and a flow rate monitor 31 is installed in the outlet channel. The monitoring results of the two monitors are used as standards to adjust the pressure in the steam cavity and the flow rate in the outlet channel in real time. This increases the stability of the pressure in the steam cavity and the flow rate in the outlet channel, greatly improves the inflation effect, and thus improves the subsequent coating effect. It is highly practical and has a simple structure.

[0056] An explosion-proof polyester needle-punched felt produced by the above-mentioned production method of explosion-proof polyester needle-punched felt, wherein the polyester needle-punched felt has a 4-layer structure, and the 3 layers of the polyester needle-punched felt are all made by mixing polyester fibers and antistatic fibers, combing and mixing them into a web, and then needle-punching the three-layer mixed fiber web into a felt through a needle-punching process.

[0057] Polyester fiber and antistatic fiber are mixed evenly in a weight ratio of 40-60:20-30, and the length of the antistatic fiber is between 2-3 cm. The antistatic fiber is one or more of metal fiber or organic polymer-based metal complex antistatic fiber.

[0058] The antistatic microporous membrane and the mixed fiber felt are coated on one side by steam hot pressing to obtain a coated filter material. The coated surface of the antistatic microporous membrane is the windward side of the polyester needle-punched felt. The antistatic material in the antistatic microporous membrane contains at least an antistatic organic polymer.

[0059] The explosion-proof polyester needle-punched felt prepared by the above method has a four-layer needle-punching structure, which is made by needle-punching three layers of mixed fiber web. The mixed fiber web is then hot-pressed and coated on one side of the windward side, which greatly increases the antistatic and explosion-proof effect of the needle-punched felt. Moreover, the weight ratio of polyester fiber and antistatic fiber is also designed to ensure that the antistatic effect of the needle-punched felt is greatly increased while maintaining the corresponding structural strength. It is highly practical and the antistatic range is also greatly improved.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing explosion-proof polyester needle-punched felt, characterized in that, The process includes the following steps: S1. Preparation of antistatic microporous membrane: Antistatic material is added to polytetrafluoroethylene resin raw material. After the above materials are mixed evenly, they are introduced into an extruder and obtained by extrusion, calendering, stretching and heat setting. The thickness is 15-30μm, the porosity is 50%-85%, and the pore size distribution is 0.3-5μm. The obtained antistatic microporous membrane is used as a preparatory material. The extrusion temperature is 200℃-300℃, the calendering pressure is 200N-500N, the biaxial stretching is made to a thickness of 5-50μm, and the heat setting temperature is 150℃-180℃. S2. Preparation of mixed fiber felt: Polyester fiber and antistatic fiber are mixed evenly at a weight ratio of 40-60:20-30 to obtain mixed fiber; the mixed fiber is fed into a carding machine by a cotton feeder to form a mixed fiber web; the mixed fiber web is conveyed to a cotton spreading machine, and multiple layers of mixed fiber web are laid to form mixed fiber felt; the mixed fiber felt is needle-punched and reinforced on a needle punching machine at a needle punching speed of 500-600 rpm to obtain a polyester needle-punched felt semi-finished product; S3. The polyester needle-punched felt semi-finished product after needle-punching reinforcement in step S2 is placed in a hot press mold (1) and hot press film is applied under vacuum. The windward side of the polyester needle-punched felt semi-finished product is the hot press film surface. S4. Place the semi-finished polyester needle-punched felt after step S3 into a cooling fixture and cool and shape it at room temperature for 60 to 70 seconds. S5. Cut the polyester needle-punched felt semi-finished product cooled in step S4 into the required external dimensions to obtain the finished polyester needle-punched felt. The hot press mold (1) includes an upper mold and a lower mold. The hot press mold (1) includes a steam channel (10) and a flow rate control mechanism disposed in the steam channel (10). The flow rate control mechanism includes an adjustment channel (2) disposed in the steam channel (10), an regulator (20) disposed in the adjustment channel (2), and a lifting device (21) for driving the regulator (20) to rise and fall and adjusting the air output of the adjustment channel (2). The regulator (20) is configured such that when it descends to the air output channel of the adjustment channel (2), the regulator (20) and the inner wall of the air output channel form an annular flow channel (201); when it is driven away from the air output channel by the lifting device (21), the air output channel restores its original air output. A flow regulation structure is also provided between the regulator (20) and the air outlet channel. The flow regulation structure includes several stepped structures (202) set on the regulator (20). The difference in outer diameter between two adjacent stepped structures (202) is between 2cm and 5cm, and the difference between two adjacent stepped structures (202) is the same. A first-level channel (203), a second-level channel (204), and a third-level channel (205) with air volume decreasing from large to small are formed between the stepped structure (202) and the air outlet channel. The flow rate control mechanism also includes a control system, which includes a pressure monitor (30) for real-time monitoring of the upper mold steam pressure, a flow rate monitor (31) installed in the outlet channel, an electromagnetic on / off valve (32) installed on the steam channel (10), and a controller (3) for controlling the start and stop of the lifting device (21) and the on / off of the electromagnetic on / off valve (32). The controller (3) includes a receiving unit electrically connected to the pressure monitor (30) and the flow rate monitor (31) and for receiving electrical signals from the two monitors, a comparison unit for setting standard and early warning upper mold steam pressure values ​​and comparing them with the monitored values, and a control unit for controlling the on / off of the electromagnetic on / off valve (32) and the start and stop of the lifting device (21).

2. The method for producing explosion-proof polyester needle-punched felt according to claim 1, characterized in that, The specific method of hot pressing and film coating in step S3 is as follows: S31, the antistatic microporous film obtained in step S1 is coated on the polyester needle-punched felt semi-finished product. S32. Vacuum the upper mold of the hot pressing mold (1) for 10 to 20 seconds and 0.01 to 0.02 MPa. High-temperature steam is introduced at the same time as vacuuming. S33. Maintain the vacuum level and continue to introduce high-temperature steam for heating and molding. The high-temperature steam pressure is 2.5-3MPa, the inflation time is between 3min and 5min, the high-temperature steam temperature is 150-300℃, the mold pressing pressure is between 300N and 800N, and the molding time is 20-60 seconds until hot pressing is completed. S34. After hot pressing is completed, the material that has been coated is pulled by the traction equipment, the high temperature steam in the upper mold is vented, and then the subsequent material that has not been hot pressed is hot pressed and coated.

3. A method for producing explosion-proof polyester needle-punched felt according to claim 1 or 2, characterized in that, The hot pressing mold (1) is further provided with a membrane cutting structure between the upper and lower molds. The membrane cutting structure includes a side cutting groove structure (220) set on the lower mold and a side cutting protrusion (221) set on the upper mold and adapted to the side cutting groove structure (220). A shearing structure is formed between the side cutting groove structure (220) and the side cutting protrusion (221). The shearing structure is used to form a timely shearing action with the lower mold after the upper mold is pressed down, and to shear and cut the excess part of the antistatic microporous membrane.

4. A method for producing explosion-proof polyester needle-punched felt according to claim 1 or 2, characterized in that, The control method of the flow rate control mechanism in the steam channel (10) specifically includes the following steps: S330, setting the warning pressure value of the upper mold steam pressure to P0, setting the standard value of the upper mold steam pressure to P, monitoring the upper mold steam pressure value to Pt in real time, setting the flow rate warning value of the outlet channel to S, and then introducing steam. S331. During the first time period, the steam pressure value of the upper mold is monitored in real time as P1. P1 and P0 are compared by the comparison unit. If P1 is less than P0, steam continues to flow. Otherwise, if P1 is greater than P0, the regulator (20) needs to be lowered by the lifting device to reduce the steam flow and adjust to the first-level channel (203). S332. During the second time period, the steam pressure of the upper mold is monitored in real time as P2. The difference between P2 and P is △. If the value of △ is within the reasonable range of pressure control, the steam is ventilated through the first-level channel (203). If the value of △ is outside the above range, the regulator (20) needs to be lowered through the lifting device to reduce the steam flow and adjust to the second-level channel (204) for ventilation within the time ts until the value of P is reached. S333. During the above time period, the flow velocity in the outlet channel is monitored in real time as S1. If S1 is greater than S, it is judged that the airflow disturbance is large and the regulator (20) needs to be lowered by the lifting device to reduce the steam flow and adjust to the third channel (205). The adjustment time is tp. Otherwise, ventilation is carried out according to the current required ventilation volume. S334. During the tp time period, the flow velocity in the outlet channel is monitored in real time as Sp. If Sp is less than the S value, it is determined that the airflow disturbance is small, and the ventilation is adjusted to the current required ventilation volume. Otherwise, ventilation is continued through the three-stage channel (205).

5. An explosion-proof polyester needle-punched felt produced by the production method of the explosion-proof polyester needle-punched felt according to any one of claims 1-4, characterized in that, Polyester needle-punched felt has a 4-layer structure. The three layers of polyester needle-punched felt are made by mixing polyester fibers and antistatic fibers, combing and mixing them into a web, and then needle-punching the three-layer mixed fiber web to form a mixed fiber felt. Polyester fiber and antistatic fiber are mixed evenly in a weight ratio of 40-60:20-30, and the length of the antistatic fiber is between 2-3 cm. The antistatic fiber is one or more of metal fiber or organic polymer-based metal complex antistatic fiber. The antistatic microporous membrane and the mixed fiber felt are coated on one side by steam hot pressing to obtain a coated filter material. The coated surface of the antistatic microporous membrane is the windward side of the polyester needle-punched felt. The antistatic material in the antistatic microporous membrane contains at least an antistatic organic polymer.

Images