An electric heating temperature-controllable polydicyclopentadiene controllable polymerization molding method

Abstract

The application discloses a controllable polymerization forming method of electric heating temperature-controlled polydicyclopentadiene, and the method is characterized by the following steps: controlling a multi-path electric heating temperature control mechanism in a mold through a program, setting a controllable temperature gradient zone, forming a controllable temperature gradient from top to bottom and from high temperature to low temperature in a workpiece zone of a forming cavity, setting a compensation zone near a low-temperature zone of the temperature gradient zone, and then adding dicyclopentadiene glue liquid into the workpiece zone in the mold cavity until the glue liquid fills 95% of the volume of the cavity, and then starting a heater of an initiation heating zone to induce PDCPD polymerization reaction to develop in the direction of the temperature gradient, and finally forming a single-crystal polymerization workpiece. The application relates to the technical field of controllable polymerization, and the controllable polymerization forming method of electric heating temperature-controlled polydicyclopentadiene can realize perfect fitting of a polydicyclopentadiene forming piece to a mold shape, and the mechanical properties of the forming piece are stable and uniform.

Description

Technical Field

[0001] This invention relates to the field of controlled polymerization technology, specifically to a method for controlled polymerization molding of polydicyclopentadiene using electrothermal temperature control. Background Technology

[0002] PDCPD is a homopolymer or copolymer of dicyclopentadiene, a cross-linked three-dimensional network structure engineering plastic. Polydicyclopentadiene is environmentally friendly, lightweight, has excellent physical and mechanical properties, excellent impact strength, good temperature resistance, especially low temperature resistance, and its performance does not decrease even at -55℃. It is also corrosion-resistant and aging-resistant.

[0003] However, under traditional polymerization processes, polydicyclopentadiene can only produce a surface that perfectly fits the mold shape, while uncontrollably generating pores inside. Furthermore, its various physical properties are unevenly distributed. The formation mechanism mainly involves the following two points:

[0004] 1. Dicyclopentadiene DCPD density is 0.985, and polydicyclopentadiene density is 1.03. Without compensation design during polymerization, 7% volume shrinkage will occur. Traditional processes control the shrinkage zone on the low-temperature side by using the temperature difference between the two sides of the mold, but it is difficult to avoid the generation of pores.

[0005] 2. Traditional processes do not involve precise temperature control, which often causes the polymerization process to start from the two sides with higher temperatures. This results in the polymerization process appearing as two (or more) polymers spliced ​​together in the middle, leading to uneven distribution of material properties and unstable mechanical structure.

[0006] Therefore, it is necessary to implement certain controls on the existing polydicyclopentadiene polymerization process. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a controllable polymerization molding method for polydicyclopentadiene with electrothermal temperature control, which solves the problems of pores in polydicyclopentadiene polymerized parts, uneven overall performance distribution, and unstable mechanical structure.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: a controllable polymerization molding method for polydicyclopentadiene with electrothermal temperature control, characterized in that: a multi-channel electrothermal temperature control mechanism in the mold is controlled by a program to set a controllable temperature gradient zone, forming a controllable temperature gradient from top to bottom and from high temperature to low temperature in the workpiece area of ​​the cavity; a compensation zone is set near the low temperature zone of the temperature gradient zone; the temperature gradient zone can be temperature-controlled according to the progress of the polymerization reaction; dicyclopentadiene adhesive is added to the workpiece area in the mold cavity until 95% of the cavity volume is filled, inducing the PDCPD polymerization reaction to develop in the direction of the temperature gradient, and finally forming a single crystal polymerized workpiece.

[0009] Preferably, the workpiece area is provided with a glue inlet and a vent.

[0010] Preferably, the electric heating temperature control mechanism includes insulation cotton, heating wire and heat-conducting plate.

[0011] Preferably, a temperature sensor is provided behind the workpiece area. The temperature sensor is used to detect the temperature of the temperature gradient zone inside the mold and then display it digitally on the display.

[0012] Preferably, the mold is further provided with an initiation heating zone, which is heated by an electric heating wire to provide an instantaneous initiation temperature for the polymerization reaction of polydicyclopentadiene.

[0013] Preferably, the compensation zone consists of a temperature-controlled cooler and a piston-driven device, and at least two compensation zones are connected outside the workpiece zone, with the total volume of the compensation zone being 7-12% of the workpiece zone.

[0014] Beneficial effects

[0015] This invention provides a method for controlled polymerization molding of polydicyclopentadiene using electrothermal temperature control. Compared with the prior art, it has the following advantages:

[0016] This electrothermal temperature-controlled polydicyclopentadiene (PDCPD) controlled polymerization molding method uses electrothermal temperature control to continuously change the temperature gradient zone according to the design, inducing the PDCPD polymerization reaction to develop in the designed direction, ultimately forming a "single crystal" polymerized workpiece. Simultaneously, a compensation zone is set up so that the PDCPD temperature in the workpiece zone differs from that in the compensation zone. While the PDCPD in the workpiece zone solidifies, the PDCPD in the compensation zone remains in an uncured liquid state. As the PDCPD in the workpiece zone solidifies and shrinks, its volume decreases, and it quickly loses its fluidity, the PDCPD in the compensation zone remains a highly fluid liquid, compensating for the shrinkage in the workpiece zone and preventing the formation of pores. This results in a perfect fit between the polydicyclopentadiene molded part and the molded part, which is pore-free and has stable and uniform mechanical properties. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the electric heating temperature control mechanism in the mold of the present invention when they are arranged at equal intervals;

[0018] Figure 2 This is a schematic diagram of the structure of the electrothermal temperature control mechanism of the present invention;

[0019] Figure 3 This is a schematic diagram of the internal temperature gradient region of the mold of the present invention;

[0020] Figure 4 This is a schematic diagram of the structure of the electric heating temperature control mechanism in the mold of the present invention when the spacing is adjusted;

[0021] Figure 5 This is a side view of the structure of the electric heating temperature control mechanism in the mold of the present invention when they are arranged at equal intervals;

[0022] Figure 6 This is a front view of the structure of the electric heating temperature control mechanism of the present invention when the spacing is adjusted.

[0023] Figure 7 This is a schematic diagram of the injection-type structure used in the compensation area of ​​the present invention;

[0024] Figure 8 This is a circuit diagram of the electrothermal temperature control mechanism of the present invention;

[0025] Figure 9 This is a schematic diagram of the temperature gradient in the workpiece region at the start of the polymerization reaction of this invention;

[0026] Figure 10 This is a schematic diagram of the temperature gradient in the workpiece region during the polymerization reaction process of this invention;

[0027] Figure 11 This is an infrared thermal image of the initial stage of the polymerization reaction in this invention;

[0028] Figure 12 This is an infrared thermal image of the polymerization reaction development stage of the present invention.

[0029] In the diagram: 1-Mold, 2-Workpiece area, 3-Compensation area, 4-Temperature gradient area, 5-Electric heating temperature control mechanism, 51-Insulation cotton, 52-Heating wire, 53-Heat conduction plate, 6-Glue inlet, 7-Exhaust port, 8-Initiation heating area, 9-Relay, 10-Microcontroller, 11-Power supply, 12-Temperature sensor, 13-Piston pushing device, 14-Temperature control cooler. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figure 1-12 This invention provides a technical solution: a method for controlled polymerization molding of polydicyclopentadiene using electrothermal temperature control, specifically comprising:

[0032] S1. Power on the electric heating temperature control mechanism in the temperature gradient zone inside the mold. When the temperature reaches 60℃, maintain temperature balance and introduce 40℃ coolant into the temperature control cooling of the compensation zone.

[0033] S2. Add dicyclopentadiene adhesive from the sprue into the workpiece area of ​​the mold cavity until the mold is 95% full. Stretch the piston in the compensation area to fill it with dicyclopentadiene adhesive.

[0034] S3. Adjust the parameters of the multi-channel electric heating temperature control mechanism in the temperature gradient zone to create a temperature gradient of 60-40℃ in the mold cavity;

[0035] S4. Turn on the heater in the initiation heating zone, control the temperature at 80℃, and after controlling the temperature for 2-3 minutes, the polymerization reaction begins in the workpiece area inside the cavity;

[0036] S5. As the polymerization reaction occurs, adjust the parameters of the multi-channel electric heating temperature control mechanism in the temperature gradient zone to form a temperature gradient of 100-75℃ in the workpiece area of ​​the mold cavity. At this time, due to the negative pressure, the dicyclopentadiene adhesive in the piston device of the compensation zone will be sucked into the workpiece area of ​​the cavity to replenish the shrinkage volume. After 4-6 minutes, the peak of the polymerization reaction passes through the entire interior of the mold along the direction of the temperature gradient, and the polymerization reaction ends.

[0037] S6. After the polymerization reaction is complete, adjust the temperature control program to keep the temperature gradient zone at 100℃ for 3-5 minutes, and then turn off the electric heating temperature control mechanism in the temperature gradient zone.

[0038] S7. The polymerization and curing process of polydicyclopentadiene is completed, and demolding and part removal operations are carried out. The controlled polymerization molding process is completed.

[0039] Please see Figure 1-2 The temperature sensor is positioned 5mm behind the workpiece area, at the same horizontal level as the electric heating temperature control mechanism. This mechanism, composed of insulation cotton, heating wire, and a heat-conducting plate, is located 35mm from the workpiece area on the back of the mold. When energized, the heating wire conducts heat through the heat-conducting plate to the temperature gradient zone. The temperature sensor detects the temperature within this gradient zone and displays it digitally. Within the temperature gradient zone, multiple electric heating temperature control mechanisms are installed. A microcontroller controls the on / off state of relays to heat the heating wire, thereby achieving a preset temperature balance.

[0040] Please see Figure 3-7There are two ways to set up multiple electrothermal temperature control mechanisms in the temperature gradient zone. The first is to set up multiple equidistant electrothermal temperature control mechanisms in the temperature gradient zone and achieve temperature gradient control by controlling the current on and off. The second is to adjust the spacing of the electrothermal temperature control mechanisms to control the current on and off to achieve temperature gradient control. Compared with the first method, the first method takes less time and has a better temperature control effect, while the second method is more energy-efficient because it can reduce the number of electrothermal temperature control mechanisms. Both methods can form a preset, gradually decreasing temperature range from top to bottom and from high temperature to low temperature within the mold cavity. Specifically, each temperature gradient from top to bottom is 3-5℃, the overall temperature gradient is 15-30℃, the temperature gradient is controlled at 60-40℃ before the polymerization reaction begins, and the temperature gradient is controlled at 100-75℃ during the polymerization reaction. Throughout the process, the temperature range of the high-temperature zone is 45-100℃, and the temperature range of the low-temperature zone is 40-75℃. Through the continuous temperature gradient, the PDCPD polymerization reaction is induced to develop in the designed direction, ultimately forming a "single crystal" polymerized workpiece.

[0041] The compensation zone is located outside the workpiece zone and is driven by a piston. A cooling device is installed at the connection with the workpiece zone. During the PDCPD polymerization reaction curing process, the workpiece zone generates negative pressure, and the PDCPD liquid in the compensation zone compensates the mold cavity workpiece zone.

[0042] The principle of the compensation and elimination of porosity technology: During the curing reaction, due to the density difference between solid polydicyclopentadiene (density 1.03) and liquid dicyclopentadiene adhesive (density 0.985), the liquid dicyclopentadiene adhesive undergoes volume shrinkage when curing into solid polydicyclopentadiene material, thus generating defects such as pores and sprues. A compensation zone needs to be designed to compensate for the porosity caused by volume shrinkage during curing. Simultaneously, the compensation zone must ensure sufficient fluidity and not cure before the workpiece area inside the mold; therefore, temperature control is required.

[0043] The principle of controlled polymerization of polydicyclopentadiene: The curing reaction is an exothermic process, therefore, only a stable temperature gradient is needed to achieve controlled polymerization. During controlled polymerization, a polymerization wave is formed. When the direction of the mold temperature gradient is the same as the direction of the polymerization wave, a stable polymerization wave is formed from one end of the mold to the other. Polydicyclopentadiene materials polymerized in this way have stable mechanical properties (deviation of various mechanical property indicators is less than 5%), consistent material integrity, and no mechanical structural weaknesses.

[0044] Specifically, the design goal of the temperature gradient zone is to create a continuous temperature gradient from high to low temperature within the mold cavity. This continuous temperature gradient induces the PDCPD polymerization reaction to develop in the designed direction, ultimately forming a "single-crystal" polymerized workpiece. The temperature gradient zone employs electrothermal temperature control, allowing the temperature within the mold cavity to be controlled as needed.

[0045] Polymerization reactions generate a lot of heat. After the polymerization reaction begins, the temperature of the mold has a negligible effect on the polymerization reaction. At this time, the purpose of setting the temperature gradient zone in the mold is to control the polymerization wave so that the polymerization wave moves stably from one end to the other.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlled polymerization molding of polydicyclopentadiene using electrothermal temperature control, characterized in that: By controlling the multi-channel electric heating temperature control mechanism in the mold through the program, a controllable temperature gradient zone is set to form a controllable temperature gradient from top to bottom and from high temperature to low temperature in the workpiece area of ​​the cavity. A compensation zone is set near the low temperature zone of the temperature gradient zone. The temperature gradient zone can regulate the temperature according to the progress of the polymerization reaction. Dicyclopentadiene adhesive is added to the workpiece area in the mold cavity until it fills 95% of the cavity volume, inducing the PDCPD polymerization reaction to develop in the direction of the temperature gradient, and finally forming a single crystal polymerized workpiece. The mold is also equipped with an initiation heating zone, which is heated by an electric heating wire to provide an instantaneous initiation temperature for the polymerization reaction of polydicyclopentadiene. The controlled polymerization molding method includes the following specific steps: S1. Power on the electric heating temperature control mechanism in the temperature gradient zone inside the mold. When the temperature reaches 60℃, maintain temperature balance and introduce 40℃ coolant into the temperature control cooling of the compensation zone. S2. Add dicyclopentadiene adhesive from the sprue into the workpiece area of ​​the mold cavity until the mold is 95% full. Stretch the piston in the compensation area to fill it with dicyclopentadiene adhesive. S3. Adjust the parameters of the multi-channel electric heating temperature control mechanism in the temperature gradient zone to create a temperature gradient of 60-40℃ in the mold cavity; S4. Turn on the heater in the initiation heating zone, control the temperature at 80℃, and after controlling the temperature for 2-3 minutes, the polymerization reaction begins in the workpiece area inside the cavity; S5. As the polymerization reaction occurs, adjust the parameters of the multi-channel electric heating temperature control mechanism in the temperature gradient zone to form a temperature gradient of 100-75℃ in the workpiece area of ​​the mold cavity. At this time, due to the negative pressure, the dicyclopentadiene adhesive in the piston device of the compensation zone will be sucked into the workpiece area of ​​the cavity to replenish the shrinkage volume. After 4-6 minutes, the peak of the polymerization reaction passes through the entire interior of the mold along the direction of the temperature gradient, and the polymerization reaction ends. S6. After the polymerization reaction is complete, adjust the temperature control program to keep the temperature gradient zone at 100℃ for 3-5 minutes, and then turn off the electric heating temperature control mechanism in the temperature gradient zone. S7. The polymerization and curing process of polydicyclopentadiene is completed, and demolding and part removal operations are carried out. The controlled polymerization molding process is completed.

2. The method for controlled polymerization molding of polydicyclopentadiene with electrothermal temperature control according to claim 1, characterized in that: The workpiece area is equipped with a glue inlet and a vent.

3. The method for controlled polymerization molding of polydicyclopentadiene with electrothermal temperature control according to claim 1, characterized in that: The electric heating temperature control mechanism includes insulation cotton, heating wire and heat-conducting plate.

4. The method for controlled polymerization molding of polydicyclopentadiene with electrothermal temperature control according to claim 3, characterized in that: A temperature sensor is installed behind the workpiece area. The temperature sensor is used to detect the temperature in the temperature gradient zone inside the mold, and then the temperature is displayed digitally on the display.

5. The method for controlled polymerization molding of polydicyclopentadiene with electrothermal temperature control according to claim 1, characterized in that: The compensation zone consists of a temperature-controlled cooler and a piston-driven device. At least two compensation zones are connected outside the workpiece zone, and the total volume of the compensation zone is 7-12% of the workpiece zone.

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