Device for regulating and controlling orientation of agricultural injection molding product and forming method

Abstract

The invention belongs to the technical field of high polymer material processing, and discloses a device for regulating and controlling the orientation of an agricultural injection molding product and a forming method. The device is provided with a mold storage chamber internally provided with a piston, and the piston is matched with a screw to move. According to the forming method for regulating and controlling the orientation of the agricultural injection molding product, after part of melt in the charging barrel storage chamber is injected into the mold cavity and the mold storage chamber, the macromolecule orientation regulating and controlling function is started, and the piston and the screw rod are driven to jointly move according to preset process parameters; the extrusion device is used for extruding the melt to force the melt in the mold cavity and the material storage chamber of the charging barrel to alternately flow at a high speed and bear high pressure, so that the molecular chain is induced to circularly shear and orientate and controllably loosen in a reciprocating manner, and the controllable orientation state of the molecular chain is stored along with layer-by-layer condensation of the agricultural injection molding product. According to the forming method, partial relaxation of the oriented molecular chain can be controllably realized to induce formation of a crystal structure with a complex structure, so that the service performance of an agricultural injection molding product is enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material processing, and particularly relates to a device for regulating the orientation of agricultural injection-molded products and a molding method. Background Art

[0002] Agricultural plastic products such as crop seedling containers, rice seedling trays, and plant sprinklers are mainly manufactured by injection molding. The service performance of agricultural injection molding products will affect the growth and development of crops and plants. The service performance of agricultural injection molding products mainly depends on the polymer crystal structure. The formation of polymer crystal structure is often related to the change in the orientation state of its molecular chain under the action of flow and pressure during the injection molding process.

[0003] In conventional injection molding, the melt in the barrel storage chamber and the mold cavity will experience a long period of no flow and no pressure, causing the molecular chain to relax rapidly from the oriented state to the random coil state, and the polymer will crystallize into non-oriented crystal structures such as spherulites, resulting in poor service performance of the injection molded product. The prior art simply applies shear vibration, pressure vibration or shear-pressure coupling vibration to the melt in the mold cavity or barrel to obtain highly oriented molecular chains, but does not induce partial relaxation of the molecular chains after orientation. For example, Chinese patent CN1507999A discloses a hot runner injection molding dynamic pressure holding device, which uses a pressure piston designed on a hot runner plate to continuously reciprocate during the pressure holding stage to generate a shear stress field, a tensile stress field, and a tensile-shear composite stress field in the mold cavity, thereby changing the polymer condensed state structure and performance; the patent only applies shear vibration or pressure vibration to the melt in the mold cavity. Chinese patent CN1164409C discloses a polymer melt vibration molding device, which uses the reciprocating motion of a vibration rod in a barrel to force the melt in the barrel storage chamber to be compressed and released, and uses a vibration shuttle connected to the vibration rod to force the melt to flow back and forth between the grooves and gaps on its surface and withstand strong shear; this patent only applies shear vibration and pressure vibration to the melt in the barrel storage chamber at the same time. Chinese patent CN102310517B discloses a piezoelectric dynamic plasticizing molding device and its injection molding method, which uses a piezoelectric ceramic drive system to generate vibration to drive the screw to reciprocate with small amplitude, high frequency, and high acceleration, thereby applying periodic pressure and shearing to the melt in the barrel; this patent only applies shear pressure coupled vibration to the melt in the barrel. Therefore, there is currently a lack of a device and molding method that can regulate the orientation of injection molded products, making it difficult to induce the orientation of molecular chains and then controllably relax partially. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a device for regulating the orientation of agricultural injection-molded products.

[0005] The device for regulating the orientation of agricultural injection molded products of the present invention is designed with a mold storage chamber and a piston is installed inside the mold storage chamber. The piston is connected to a driver so that it can cooperate with the movement of the screw.

[0006] Another object of the present invention is to provide a molding method for regulating the orientation of agricultural injection-molded products based on the above device.

[0007] The molding method for regulating the orientation of agricultural injection molding products of the present invention is to start the function of regulating the orientation of polymers after part of the melt in the barrel storage chamber is injected into the mold cavity and the mold storage chamber, and drive the piston installed in the mold storage chamber and the screw installed in the barrel to perform joint movement at preset process parameters such as speed, pressure, and time, so as to force the melt in the mold cavity and the barrel storage chamber to alternately flow at high speed and withstand high pressure, thereby inducing the molecular chain to cyclically shear orientation and controllable relaxation, and as the agricultural injection molding products condense layer by layer, the controllable orientation state of the molecular chain is preserved. This molding method can controllably achieve partial relaxation of the oriented molecular chain to induce the formation of a complex crystal structure, thereby enhancing the service performance of the agricultural injection molding products.

[0008] The purpose of the present invention is achieved through the following solutions: A device for regulating the orientation of an injection-molded product for agriculture, comprising an injection device and a mold device; In the injection device, a screw is installed in the barrel and connected to a first driver; In the mold device, the mold storage chamber is connected to the mold cavity through a gate; a piston is arranged in the mold storage chamber; a perfluoroether rubber sealing ring is arranged on the piston; the piston is connected to the second driver; a first cooling water channel is arranged around the mold storage chamber; and a second cooling water channel is arranged around the mold cavity.

[0009] The injection device and the mold device are connected through the nozzle of the injection device and the gate sleeve of the mold device.

[0010] A heating ring is installed outside the barrel and a hopper for feeding materials is installed at the end; the cavity formed by the screw and the barrel is the barrel storage chamber.

[0011] The connection between the piston and the second driver is specifically as follows: a piston rod is connected to the rear end of the piston; the piston rod extends to the outside of the mold device through a channel on the mold device; and outside the mold device, the piston rod is connected to the second driver.

[0012] The first cooling water route is regulated by a first mold temperature controller, and the second cooling water route is regulated by a second mold temperature controller.

[0013] The first driver is a combination of a rotating device and a linear motion device; the rotating device includes one of an oil motor and an electric motor; the linear motion device includes one of a hydraulic cylinder and a ball screw.

[0014] The second driver is a linear motion device, including one of an electric cylinder, a hydraulic cylinder, and a linear motor.

[0015] The piston rod is connected to the second driver via a connecting piece, wherein the connecting piece comprises one of a thread, a fisheye joint, and a Y-type joint.

[0016] The mold storage chamber, the piston, the piston rod, and the second driver form a piston drive system; one or more piston drive systems are arranged in the mold device.

[0017] The first cooling water channels are symmetrically distributed around the mold storage chamber; and the second cooling water channels are symmetrically distributed around the mold cavity.

[0018] A molding method for regulating the orientation of agricultural injection molded products based on the above-mentioned device comprises the following steps: putting a polymer material into a hopper, heating it in a barrel to form a melt, and injecting part of the melt in the barrel storage chamber into a mold cavity and a mold storage chamber; starting the function of regulating the polymer orientation, driving the piston and the screw to move jointly according to preset process parameters, so that the melt in the mold cavity and the barrel storage chamber is alternately flow-sheared and pressurized until the melt is cooled to room temperature, thereby obtaining an agricultural injection molded product.

[0019] The molding method for regulating the orientation of an agricultural injection molded product specifically comprises the following steps: (1) Using a heating ring to heat the barrel to a preset temperature; using a first mold temperature controller to adjust the temperature of the first cooling water channel; using a second mold temperature controller to adjust the temperature of the second cooling water channel; starting the first driver to rotate the screw in the barrel; (2) Put the polymer material into the hopper, use the temperature of the barrel and the rotation of the screw to plasticize it into a melt and transport it to the barrel storage chamber; (3) Start the second driver to move the piston installed in the mold backward to the bottom; start the first driver to move the screw installed in the barrel forward in the axial direction, so that part of the melt in the barrel storage chamber is injected into the mold cavity and the mold storage chamber; (4) Start the polymer orientation control function to make the melt in the mold cavity and the barrel storage chamber flow shear and pressurize alternately until the melt in the mold cavity cools to room temperature to obtain an injection molded product.

[0020] Step (1) The temperature of the first cooling water channel satisfies: cooling the polymer material in the mold storage chamber to a highly elastic state.

[0021] Step (1) The temperature of the second cooling water channel satisfies: cooling the polymer material in the mold cavity to room temperature.

[0022] The step (4) of regulating the polymer orientation function comprises the following steps: 1) Start the first driver to make the screw installed in the barrel move backward, and start the second driver to make the piston installed in the mold storage chamber move forward, so as to push the melt from the mold cavity to the barrel storage chamber for flow shearing; 2) In the opposite operation, the second driver is started to move the piston installed in the mold storage chamber backward to the bottom to fit the mold wall to form an end face seal, and at the same time, the first driver is started to move the screw installed in the barrel forward, thereby pushing the melt from the barrel storage chamber to the mold cavity for flow shearing; 3) The first drive continues to push the screw in the barrel forward to apply pressure to the melt in the barrel storage chamber and the mold cavity; 4) The first drive drives the screw in the barrel to move backward to perform a loosening action, thereby reducing the melt pressure in the barrel storage chamber and the mold cavity; 5) Repeat steps 1) to 4) to alternately subject the melt in the mold cavity and the barrel storage chamber to flow shear and pressurization, thereby achieving the function of regulating the orientation of the polymer.

[0023] The relationship between the movement speeds of the screw and the piston in step 1) and step 2) is as follows: , Where d is the diameter and N is the number of piston drive systems.

[0024] The mechanism of the present invention is: In the present invention, when the melt flows at high speed, the molecular chains are subjected to strong shearing and are oriented along the flow direction; the melt is then subjected to high pressure, so the mobility of the oriented molecular chains is reduced due to the reduction of free volume, and the speed at which they relax to the random coil state is slowed down, thereby achieving partial relaxation of the oriented molecular chains in a controllable manner, which can induce the formation of a complex crystal structure and enhance the service performance of the injection molded product.

[0025] Therefore, the present invention drives the melt in the barrel storage chamber and the mold cavity to flow alternately at high speed and withstand high pressure during injection molding, thereby promoting the reciprocating shear orientation and controllable relaxation of the molecular chains, thereby controllably achieving partial relaxation of the oriented molecular chains, and preserving the controllable orientation state of the molecular chains as the injection molded products condense layer by layer, thereby hopefully inducing the formation of a complex crystal structure and enhancing the service performance of injection molded products for agricultural use.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Through the linkage of piston and screw, the melt in the mold cavity and the barrel storage chamber can be driven to flow at high speed and withstand high pressure alternately, so as to induce the molecular chain to shear orientation and partial relaxation cyclically, and as the agricultural injection molded products condense layer by layer, the controllable orientation state of the molecular chain is preserved.

[0027] 2. By adjusting the piston and screw motion parameters, the orientation and relaxation behavior of the molecular chain can be precisely controlled, and the partial relaxation of the oriented molecular chain can be controllably achieved to induce the formation of a complex crystal structure, thereby enhancing the service performance of agricultural injection molding products.

[0028] 3. The orientation and relaxation of molecular chains can be regulated with a simple mechanical structure and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of the device for regulating the orientation of agricultural injection molded products according to the present invention; Among them, 1-the second driver; 2-connecting piece; 3-piston rod; 4-piston; 5-perfluoroether rubber sealing ring; 6-the first cooling water circuit; 7-the second cooling water circuit; 8-mold storage chamber; 9-gate; 10-mold cavity; 11-barrel storage chamber; 12-barrel; 13-screw; 14-heating coil; 15-hopper; 16-first driver.

[0030] Figure 2 It is a schematic diagram of the connection method between the nozzle of the injection device and the gate sleeve of the mold device.

[0031] Figure 3 It is a connection scheme diagram of the cooling water circuit and the mold temperature controller; among them, 17 is the first mold temperature controller; 18 is the second mold temperature controller.

[0032] Figure 4 The present invention is a schematic diagram of the process flow of the molding method for regulating the orientation of agricultural injection molded products. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0034] Unless otherwise specified, the reagents used in the examples can be purchased from the market.

[0035] A device for regulating the orientation of agricultural injection molded products, the structure of which is as follows Figure 1 As shown, the device includes an injection device and a mold device. Figure 2 As shown, during injection molding, the nozzle 19 on the injection device will contact the gate sleeve 20 on the mold device to connect the barrel storage chamber 11 with the mold cavity 10.

[0036] In the above injection device, the screw 13 is installed in the barrel 12 and connected to the first driver 16; the heating ring 14 is installed outside the barrel; the end of the barrel 12 is punched with a hopper 15, and the hopper 15 is connected to the inside of the barrel 12; The first driver 16 is a combination of an oil motor and a hydraulic cylinder, which respectively drives the screw to perform rotational motion and linear motion.

[0037] In the above-mentioned mold device, two mold storage chambers 8 are designed around the mold cavity 10; a gate 9 is designed to connect the mold storage chamber 8 with the mold cavity 10; a piston 4 is installed in the mold storage chamber 8; a gap is used between the piston 4 and the mold wall to ensure that the piston 4 can reciprocate back and forth in the mold storage chamber 8; a high-temperature resistant perfluoroether rubber sealing ring 5 is installed on the piston 4 to prevent the high-temperature and high-pressure melt from leaking to the rear of the piston through the gap between the piston 4 and the mold wall; a piston rod 3 is connected to the rear end of the piston 4; the piston rod 3 extends to the outside of the mold through the channel designed on the mold; outside the mold, the piston rod 3 is connected to the second driver 1 through the connecting piece 2; a first cooling water path 6 is designed around the mold storage chamber 8; a second cooling water path 7 is designed around the mold cavity 10; Figure 3 As shown, the first cooling water circuit 6 is connected to the first mold temperature controller 17 through a pipeline; the second cooling water circuit 7 is connected to the second mold temperature controller 18 through a pipeline.

[0038] The mold storage chamber 8, piston 4, piston rod 3, and second driver 1 described above form a piston drive system, and multiple sets of piston drive systems can be designed on the mold. Figure 1 The symmetrical design has two piston drive systems.

[0039] The second driver 1 is an electric cylinder that drives the actuator to perform linear motion.

[0040] The connector 2 is a threaded connector for connecting the second driver 1 and the piston rod 3 .

[0041] The first cooling water channel 6 is evenly and symmetrically distributed around the mold material storage cavity 8 ; the second cooling water channel 7 is evenly and symmetrically distributed around the mold cavity 10 .

[0042] Example 1 This embodiment uses the above device to implement an injection molding method for regulating polymer orientation, and its process flow is as follows: Figure 4The barrel 12 is heated to a preset temperature by the heating coil 14; the temperature of the first cooling water channel 6 is adjusted by the first mold temperature controller 17 to cool the polyolefin in the mold storage chamber 8 to a high elastic state; the temperature of the second cooling water channel 7 is adjusted by the second mold temperature controller 18 to cool the polyolefin in the mold cavity 10 to room temperature; the first driver 16 is started to rotate the screw 13 in the barrel 12; the polyolefin is put into the hopper 15, and the high temperature of the barrel 12 and the rotation of the screw 13 are used to plasticize it into a melt and transport it to the barrel storage chamber 11; the second driver 1 is started to make the piston 4 installed in the mold rotate at a speed of 10. v 1 Backward (+ y start the first driver 16 so that the screw 13 installed in the barrel 12 moves in the axial direction at a speed v 2 forward (+ x direction), thereby moving part of the melt in the barrel storage chamber 11 under pressure p 1 is injected into the mold cavity 10 and the mold storage chamber 8; the polymer orientation control function is started to make the piston 4 installed in the mold storage chamber 8 and the screw 13 installed in the barrel 12 move according to the preset process parameters; after the process is completed, the injection molded product cooled to room temperature in the mold cavity 10 is taken out, thereby completing an injection molding cycle.

[0043] The above-mentioned function of adjusting the orientation of polymers is to start the first driver 16 so that the screw 13 installed in the barrel 12 moves at a speed of v 3 Backward (- x direction), and at the same time, the second driver 1 is started to make the piston 4 installed in the mold storage chamber move at a speed v 4 forward (- y direction) movement, thereby p 2 pushes the melt from the mold cavity 10 to the barrel storage chamber 11 at high speed, wherein the flow time t 1; then reverse operation, start the second drive 1 so that the piston 4 installed in the mold storage chamber moves at a speed v 5 Backward (+ y The first drive 16 is started to move the screw 13 installed in the barrel 12 at a speed of v 6 forward (+ x direction) movement, thereby p 3 pushes the melt to flow from the barrel storage chamber 11 to the mold cavity 10 at high speed, wherein the flow time t 2; The first drive 16 continues to push the screw 13 in the barrel 12 at a speed v 7 forward (+ x direction) to exert pressure on the melt in the barrel storage chamber 11 and the mold cavity 10 for a certain period of time. t 3 high pressure p4; The first driver 16 drives the screw 13 in the barrel 12 at a speed v 8 and time t 4 Backward (- x The melt pressure in the barrel storage chamber 11 and the mold cavity 10 is reduced by moving a little in the direction of the cylinder to perform a loosening action, thereby reducing the melt pressure in the barrel storage chamber 11 and the mold cavity 10. p 5; The above steps are performed repeatedly, and the number of execution cycles is set by the process parameters, so that high-speed flow and high pressure can be applied alternately to the melt in the barrel storage chamber 11 and the mold cavity 10 to achieve the regulation of polymer orientation.

[0044] In order to realize the linkage between the piston 4 in the mold storage chamber 8 and the screw 13 in the barrel 12, the above speed v 3 and speed v 4The following relationship exists: ,in d 1 is the inner diameter of the barrel (also known as the screw diameter); d 2 is the inner diameter of the mold storage chamber (i.e. the piston diameter); N is the number of piston drive systems, Figure 1 middle N =2.

[0045] In order to realize the linkage between the piston 4 in the mold storage chamber 8 and the screw 13 in the barrel 12, the above speed v 5 and speed v 6The following relationship exists: .

[0046] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A device for regulating the orientation of an injection molded product for agricultural use, characterized in that: Including injection device and mold device; In the injection device, a screw is installed in the barrel and connected to a first driver; In the mold device, the mold storage chamber is connected to the mold cavity through a gate; a piston is arranged in the mold storage chamber; a perfluoroether rubber sealing ring is arranged on the piston; the piston is connected to the second driver; a first cooling water channel is arranged around the mold storage chamber; and a second cooling water channel is arranged around the mold cavity.

2. The device for adjusting the orientation of an agricultural injection molded product according to claim 1, characterized in that: The injection device and the mold device are connected via the nozzle of the injection device and the sprue sleeve of the mold device; A heating ring is installed outside the barrel and a hopper for feeding materials is installed at the end; the cavity formed by the screw and the barrel is the barrel storage chamber.

3. The device for adjusting the orientation of an injection molded product for agriculture according to claim 1, characterized in that: The connection between the piston and the second driver is specifically as follows: a piston rod is connected to the rear end of the piston; the piston rod extends to the outside of the mold device through a channel on the mold device; and outside the mold device, the piston rod is connected to the second driver.

4. The device for adjusting the orientation of an injection molded product for agriculture according to claim 1, characterized in that: The first cooling water route is regulated by a first mold temperature controller, and the second cooling water route is regulated by a second mold temperature controller.

5. The device for adjusting the orientation of agricultural injection molded products according to claim 1, characterized in that: The second driver is a linear motion device, including one of an electric cylinder, a hydraulic cylinder, and a linear motor.

6. The device for adjusting the orientation of an agricultural injection molded product according to claim 1, characterized in that: The mold material storage chamber, the piston, the piston rod, and the second driver form a piston drive system; one or more piston drive systems are arranged in the mold device.

7. A molding method for regulating the orientation of an agricultural injection molded product based on the device according to any one of claims 1 to 6, comprising the following steps: Put the polymer material into the hopper, heat it in the barrel to form a melt, and inject part of the melt in the barrel storage chamber into the mold cavity and the mold storage chamber; The polymer orientation regulating function is activated to drive the piston and the screw to move jointly according to the preset process parameters, so that the melt in the mold cavity and the barrel storage chamber is alternately flowed, sheared and pressurized until the melt is cooled to room temperature to obtain an injection molded product for agricultural use.

8. The molding method for regulating the orientation of an agricultural injection molded product according to claim 7, characterized in that: The specific steps include: (1) Using a heating ring to heat the barrel to a preset temperature; using a first mold temperature controller to adjust the temperature of the first cooling water channel; using a second mold temperature controller to adjust the temperature of the second cooling water channel; starting the first driver to rotate the screw in the barrel; (2) Put the polymer material into the hopper, use the temperature of the barrel and the rotation of the screw to plasticize it into a melt and transport it to the barrel storage chamber; (3) Start the second driver to move the piston installed in the mold backward to the bottom; start the first driver to move the screw installed in the barrel forward in the axial direction, so that part of the melt in the barrel storage chamber is injected into the mold cavity and the mold storage chamber; (4) Start the polymer orientation control function to make the melt in the mold cavity and the barrel storage chamber flow shear and pressurize alternately until the melt in the mold cavity cools to room temperature to obtain an injection molded product.

9. The molding method for regulating the orientation of an agricultural injection molded product according to claim 8, characterized in that: Step (1) The temperature of the first cooling water channel satisfies: cooling the polymer material in the mold storage chamber to a highly elastic state; Step (1) The temperature of the second cooling water channel satisfies: cooling the polymer material in the mold cavity to room temperature.

10. The molding method for regulating the orientation of an agricultural injection molded product according to claim 8, characterized in that: The step (4) of regulating the polymer orientation function comprises the following steps: 1) Start the first driver to make the screw installed in the barrel move backward, and start the second driver to make the piston installed in the mold storage chamber move forward, so as to push the melt from the mold cavity to the barrel storage chamber for flow shearing; 2) In the opposite operation, the second driver is started to move the piston installed in the mold storage chamber backward to the bottom to fit the mold wall to form an end face seal, and at the same time, the first driver is started to move the screw installed in the barrel forward, thereby pushing the melt from the barrel storage chamber to the mold cavity for flow shearing; 3) The first drive continues to push the screw in the barrel forward to apply pressure to the melt in the barrel storage chamber and the mold cavity; 4) The first drive drives the screw in the barrel to move backward to perform a loosening action, thereby reducing the melt pressure in the barrel storage chamber and the mold cavity; 5) Repeat steps 1) to 4) to alternately subject the melt in the mold cavity and the barrel storage chamber to flow shear and pressurization, thereby achieving the function of regulating the orientation of the polymer.

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