Plastic melt volume resistance tester

Abstract

The utility model provides a plastic melt volume resistance tester, which comprises a supporting seat, a lifting mechanism, an upper heating plate, a lower heating plate and an insulating plate, the upper end of the supporting seat is connected with the upper heating plate through the lifting mechanism, and the lower end of the supporting seat is provided with the lower heating plate corresponding to the upper heating plate; the insulating plate is arranged at the top of the lower heating plate, and a circular through hole for filling a to-be-tested plastic sample is formed in the middle of the insulating plate. According to the utility model, a plastic sample filled in the insulating plate is heated to a set temperature through the upper and lower metal heating plates, direct-current voltage is supplied, a current value is tested, and volume resistance and volume resistivity are calculated through voltage, current and sample size, so that the volume resistance and volume resistivity can be conveniently and quickly tested at different temperatures and different pressures. The device has the advantages of being adjustable in pressurization pressure, testing voltage and heat preservation time, convenient to operate, safe, reliable and good in repeatability.

Description

Technical Field

[0001] The utility model relates to the technical field of plastic electrical property measurement, in particular to a plastic melt volume resistivity tester. Background Art

[0002] In the application process of plastic materials, it is necessary to understand their resistance and resistivity under high temperature conditions to avoid being broken down by current and becoming ineffective. For some plastics, such as polyester films, voltage is required for surface treatment or attachment during the processing to facilitate smooth processing, and their resistance and resistivity also need to be tested. The resistance and resistivity at room temperature are easy to test, but the resistance and resistivity at high temperature, especially in the molten state, are difficult to test, and there is no commercial testing instrument yet. This is mainly because plastic materials are prone to flow, oxidative deterioration and decomposition in the molten state, and special treatment and protection of the samples are required.

[0003] The disclosed patent CN 107907746 B discloses a method for testing the melt resistivity of polymers. In this method, two heating electrodes are stacked on the test sample manually to measure the resistance value, and the test pressure and test voltage cannot be adjusted, so the test conditions are limited. The sample placement hole provided by this patent is square, and after the polymer melt melts, voids are likely to occur, resulting in errors in the test data. Content of the Utility Model

[0004] Aiming at the problems of limited test conditions and easy occurrence of errors in test data existing in the existing plastic resistivity testing device, the utility model proposes a testing device for the high-temperature volume resistance and resistivity of plastics.

[0005] The utility model adopts the following technical solutions to solve the above technical problems:

[0006] A plastic melt volume resistivity tester includes a support base, a lifting mechanism, an upper heating plate, a lower heating plate and an insulating plate. Among them: the upper end of the support base is connected to the upper heating plate through the lifting mechanism, and the lower end of the support base is installed with the lower heating plate corresponding to the upper heating plate; the insulating plate is arranged on the top of the lower heating plate, and a circular through hole for filling the plastic sample to be tested is opened in the middle of the insulating plate.

[0007] Preferably, the support base is a metal support base with a C-shaped structure.

[0008] Preferably, the lifting mechanism is vertically installed on the bracket at the upper end of the support base, and the telescopic rod arranged downward at the lower end of the lifting mechanism is connected to the upper heating plate.

[0009] Preferably, the upper heating plate and the lower heating plate are square plates with the same size, and they are made of aluminum, copper or stainless steel.

[0010] More preferably, the surface areas of the upper heating plate and the lower heating plate are 100×100 mm to 150×150 mm, and the thicknesses are 20 mm to 50 mm.

[0011] Preferably, heating wires and temperature measuring sensors are respectively arranged in the upper heating plate and the lower heating plate, and the heating wires are externally connected to an AC power supply.

[0012] Preferably, the upper heating plate and the lower heating plate are insulated and heat-insulated from other connected metal components, and are respectively connected in series through high-temperature wires, a DC power supply and an ammeter.

[0013] Preferably, the insulating plate is made of a ceramic plate, a mica plate or a fluoroplast plate, and its size is similar to that of the upper heating plate and the lower heating plate.

[0014] More preferably, the thickness of the insulating plate is 2 to 3 mm, and the diameter of the circular perforation in the middle is 20 to 30 mm.

[0015] Preferably, the plastic melt volume resistivity tester further includes an externally connected DC power supply and an ammeter, where:

[0016] The DC power supply and the ammeter are connected in series with the upper heating plate and the lower heating plate through high-temperature wires.

[0017] The present utility model adopts the above technical solutions, and compared with the prior art, has the following technical effects:

[0018] The plastic melt volume resistivity tester provided by the present utility model heats the plastic specimen filled in the insulating plate to a set temperature through the upper and lower metal heating plates, and at the same time applies a DC voltage to measure the current value. The volume resistance and volume resistivity are calculated through the voltage, current and sample size, and can be used to measure the volume resistance and resistivity of plastics at any temperature from room temperature to 500 °C; it can conveniently and quickly measure the volume resistance and resistivity at different temperatures, different pressures and different voltages, and has the characteristics of adjustable pressurization pressure, adjustable test voltage, adjustable heat preservation time, convenient operation, safety and reliability, and good repeatability. Description of the Drawings

[0019] Figure 1 is a schematic diagram of the overall structure of a plastic melt volume resistivity tester of the present utility model;

[0020] Figure 2 is a schematic diagram of the structure of an insulating block in a plastic melt volume resistivity tester of the present utility model. Detailed Embodiments

[0021] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0022] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model.

[0023] In some embodiments, such as Figure 1 and Figure 2 shown, a plastic melt volume resistivity tester is provided. The device mainly includes a support base 1, a lifting mechanism 2, an upper heating plate 3, a lower heating plate 4, an insulating plate 5, a DC power supply 6, and an ammeter 7.

[0024] Among them, the support base 1 is a metal support base with a C-shaped structure. The upper heating plate 3 is connected to the upper end of the support base 1 through the lifting mechanism 2, and the upper heating plate 3 can move up and down driven by the lifting mechanism 2; the lower heating plate 4 corresponding to the upper heating plate 3 is installed at the lower end of the support base 1; the insulating plate 5 is arranged on the top of the lower heating plate 4, and a circular perforation 51 for filling the plastic sample to be measured is provided in the middle thereof.

[0025] According to needs, the lifting mechanism 2 can adopt hydraulic lifting, pneumatic lifting or electric lifting, such as using a lifting cylinder, a hydraulic lift, an electric lead screw or an electric ball screw lifting module, etc. It is preferably hydraulic lifting and an electric lead screw. The electric lead screw has the advantages of compact and reasonable layout, large transmission ratio, stable operation, better pressure adjustment accuracy, and high-speed operation, greatly improving the work efficiency and operation stability.

[0026] In some of these embodiments, the lifting mechanism 2 is vertically installed on the bracket at the upper end of the support base 1, and the telescopic rod arranged downward at its lower end is connected to the upper heating plate 3. The lower heating plate 4 is fixedly installed on the bracket at the lower end of the support base 1, and the upper heating plate 3 and the lower heating plate 4 are insulated and heat-insulated from other connected metal components.

[0027] In some of these embodiments, the upper heating plate 3 and the lower heating plate 4 are square plates with the same size, and they are made of aluminum, copper or stainless steel. The surface areas of the upper heating plate 3 and the lower heating plate 4 are 100×100 mm to 150×150 mm, and the thickness is 20 mm to 50 mm; preferably, the thickness is 20 mm to 30 mm

[0028] In some embodiments, the upper heating plate 3 and the lower heating plate 4 are both heating plates and test electrode plates. The upper heating plate 3 and the lower heating plate 4 are respectively provided with heating wires and temperature sensors, and the heating wires are externally connected to an AC power supply.

[0029] The upper heating plate 3 and the lower heating plate 4 are heated by an external AC power supply through a heating wire, and the power supply of the heating wire is AC 220ACV, and the power is 500-1000W. The temperature of the upper heating plate 3 and the lower heating plate 4 is monitored in real time by a temperature sensor, and uploaded to a controller, and the controller is used to control the heating power of the upper heating plate 3 and the lower heating plate 4, so as to achieve the purpose of controlling the temperature of each heating plate.

[0030] In some of the embodiments, Figure 2 As shown, the insulating plate 5 is made of a ceramic plate, a mica plate or a fluoroplastic plate, preferably a fluoroplastic plate. The size of the insulating plate 5 is similar to that of the upper heating plate 3 and the lower heating plate 4.

[0031] Specifically, the surface area of the insulating plate 5 is 100×100 mm to 150×150 mm, the thickness is 2 to 3 mm, the diameter of the circular perforation 51 in the middle is 20 to 30 mm, and the circular hole in the middle is used to place the plastic particles or plastic films to be tested.

[0032] In some of the embodiments, Figure 1 As shown, the measuring device also includes an external DC power supply 6 and an ammeter 7, wherein: the DC power supply 6 and the ammeter 7 are connected in series with the upper heating plate 3 and the lower heating plate 4 through high-temperature wires to provide a DC voltage and facilitate current measurement.

[0033] In addition, in order to realize automatic and intelligent control, the test device also includes a PLC controller or other control unit, such as a computer. The DC power supply 6 and the ammeter 7 are electrically connected to the PLC controller or the computer, so that the DC voltage and current data can be transmitted to the computer through the transmitter card for data collection, and the test DC voltage, cylinder pressure, and holding time are adjustable.

[0034] like Figure 1 and Figure 2As shown, the method of using the test device for high-temperature volume resistance and resistivity of plastic is as follows: (1) The upper heating plate 3 and the lower heating plate 4 are heated to the set temperature respectively, and the upper heating plate 3 is in the raised position at this time; (2) The insulating plate 5 with a thickness of T is placed on the upper surface of the lower heating plate, and then the accurately weighed plastic sample is filled into the circular perforation 51 with an area of S on the insulating plate, and it is ensured that the filling amount can fill the circular perforation after melting; (3) The upper heating plate 3 is moved downward to the top of the insulating plate 5 by the lifting mechanism 2, and the temperature and pressure are kept; (4) A DC voltage is applied to the heating plate 3 and the lower heating plate 4, and after a certain period of time, the reading I of the ammeter 7 is read; (5) The volume resistance (Ω) is obtained by the formula: R = U / I; and the volume resistivity is obtained by the formula P = R×S / T; wherein, the area of the circular hole S (cm 2 ), T is the thickness of the insulating plate (cm), U is the voltage (v), I is the current (A), R is the volume resistance (Ω), and P is the volume resistivity (Ω×cm).

[0035] When the testing device is used for testing, an accurately weighed plastic sample is filled into the circular perforation 51 of the insulating block. The amount of the sample can be calculated based on the volume of the circular perforation 51. The insulating plate 5 is placed on the upper surface of the lower heating plate.

[0036] Before placing the sample, the upper heating plate 3 and the lower heating plate 4 are heated to the required temperature in advance, and the upper heating plate 3 is kept in the raised position. After the sample is placed, the upper heating plate 3 is moved down by the lifting mechanism 2 and pressed on the upper surface of the insulating plate 5.

[0037] Then set the required pressure, holding time and test voltage, and read the test current of ammeter 7 in time. If necessary, the test current can be input into the computer through the transmission acquisition card, and the current curve can be automatically recorded and the volume resistance and resistivity can be calculated.

[0038] After the test time reaches the set value, the lifting mechanism 2 automatically rises and the measurement ends.

[0039] It should be noted that for plastic materials that are extremely easy to absorb water and decompose, such as polyester materials and nylon materials, the samples need to be dried in an oven at 100°C for 60 minutes before testing. For materials such as polypropylene and polyethylene, they can be tested directly.

[0040] The utility model is mainly used for testing the volume resistance and resistivity of plastics under high temperature conditions, especially under melting conditions. The technical principle is to heat the plastic sample filled in the insulating plate to a set temperature through the upper and lower metal heating plates, and pass a DC voltage at the same time to test the current value. The volume resistance and resistivity are calculated by the voltage, current and sample size. It can be used to test the volume resistance and resistivity of plastics at any temperature from room temperature to 500°C.

[0041] In summary, the plastic melt volume resistivity tester can conveniently and quickly measure the volume resistivity and resistivity at different temperatures, pressures, and voltages. It has the characteristics of adjustable applied pressure, adjustable test voltage, adjustable heat preservation time, convenient operation, safety and reliability, and good repeatability. It provides a convenient test means for quality control and scientific research, and can be used for product inspection and scientific research.

[0042] Finally, the following points should be noted: First, in the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be understood in a broad sense. It can be a mechanical connection or an electrical connection, or the communication inside two components. It can be directly connected. "Up", "down", "left", "right", etc. are only used to represent the relative position relationship. When the absolute position of the object being described changes, the relative position relationship may change;

[0043] Second, in the drawings of the disclosed embodiments of the present utility model, only the structures related to the disclosed embodiments are involved. Other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present utility model can be combined with each other;

[0044] Finally, the above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A plastic melt volume resistivity tester, characterized in that, It includes a support base, a lifting mechanism, an upper heating plate, a lower heating plate and an insulating plate, wherein: the upper end of the support base is connected to the upper heating plate through the lifting mechanism, and the lower end thereof is provided with the lower heating plate corresponding to the upper heating plate; the insulating plate is arranged on the top of the lower heating plate, and a circular perforation for filling a plastic specimen to be measured is formed in the middle thereof.

2. The plastic melt volume resistivity measuring instrument according to claim 1, characterized in that, The support base is a metal support base and has a C-shaped structure.

3. The plastic melt volume resistivity tester according to claim 1, characterized in that, The lifting mechanism is vertically installed on the bracket at the upper end of the support base, and the telescopic rod arranged downward at the lower end thereof is connected to the upper heating plate.

4. The plastic melt volume resistivity tester according to claim 1, characterized in that, The upper heating plate and the lower heating plate are square plates with the same size, and are made of aluminum, copper or stainless steel.

5. The plastic melt volume resistivity tester according to claim 4, characterized in that, The surface areas of the upper heating plate and the lower heating plate are 100×100 mm to 150×150 mm, and the thickness is 20 mm to 50 mm.

6. The plastic melt volume resistivity tester according to claim 1, wherein Electric heating wires and temperature measuring sensors are respectively arranged in the upper heating plate and the lower heating plate, and the electric heating wires are externally connected to an AC power supply.

7. The plastic melt volume resistivity tester according to claim 1, characterized in that, The upper heating plate and the lower heating plate are insulated and heat-insulated from other connected metal components, and are respectively connected in series through high-temperature wires, a DC power supply and an ammeter.

8. The plastic melt volume resistivity measuring instrument according to claim 1, characterized in that The insulating plate is made of a ceramic plate, a mica plate or a fluoroplastic plate, and its size is similar to those of the upper heating plate and the lower heating plate.

9. The plastic melt volume resistivity tester according to claim 8, characterized in that, The thickness of the insulating plate is 2 to 3 mm, and the diameter of the circular perforation in the middle is 20 to 30 mm.

10. The plastic melt volume resistivity measuring instrument according to claim 1, characterized in that, It further includes an externally connected DC power supply and an ammeter, wherein: The DC power supply and the ammeter are connected in series with the upper heating plate and the lower heating plate through high-temperature wires.

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