RU2849346C1 - Device for simulating polymerisation processes of polymer materials - Google Patents

Abstract

FIELD: testing.

SUBSTANCE: invention relates to test equipment and is used in the process of making articles from filled polymer compositions, in particular for simulating polymerisation processes and determining the kinetics of hardening of polymer materials. Device for simulating polymerisation processes of polymer materials comprises a thermostat with a mixer, several pairs of moulds with a coaxial measuring rod placed in a thermostat and installed radially with respect to the loading cam, measuring rods reciprocating movement drive, consisting of loading cam and command cam installed on electric drive shaft, levers, which by one end are rigidly connected to the corresponding measuring rods, and by the other end having a roller, interact with the loading cam profile, an electrical circuit with instrumentation. Loading cam and command cam are arranged on common base, by means of which they are installed on electric drive shaft. In the loading cam in the place of its connection by means of fastening elements to the base there are slots that ensure the possibility of linear movement of the loading cam along the base and change of projection of its shaped part relative to the axis of rotation.

EFFECT: providing reciprocal-rotary movement of measuring rod to create shear deformations in reference sample from polymer material in range from 1° to 5°, which allows to test control samples in a wide range of their viscoelastic characteristics.

1 cl, 2 dwg

Description

The invention relates to testing equipment and is used in the process of manufacturing products from filled polymer compositions, and in particular, for simulating polymerization processes and determining the kinetics of curing of polymeric materials.

Russian Federation Patent No. 2220935 C06B 21/00 is known for a manufacturing method according to application No. 2002111459 dated April 29, 2002. The patent describes a method in which a control sample of a polymeric material is placed in a mold with a measuring rod, thermostatted at a temperature 10-20°C above the product's curing temperature, the measuring rod is rotated at fixed points during thermostatting by an angle of 1° - 2° within the elastic limits of the control sample to create shear deformations, the shear modulus is measured until a constant value is established, and thereby the curing time of the control sample is determined. This allows for the transfer of curing completion information from the control sample to the product, and its timely removal from polymerization.

A device for determining the curing kinetics of polymeric materials, according to A.S. No. 930061 G01N, published May 23, 1982, is considered an analogue. Its common features with the device proposed by the authors include a thermostat, levers, several pairs of coaxial cylinders mounted radially on the thermostat, and a drive for the reciprocating rotation of the internal cylinders, mounted on the cam drive shaft.

A device for determining the curing kinetics of polymeric materials is known, according to A.S. No. 220615, G01N, published June 28, 1962. In this device, a control polymer sample is placed in outer cylinders, then inner cylinders are inserted into these cylinders. The assembled cylinders containing the control sample are placed in a liquid thermostat, where they are thermostatted. Actuators are used to rotate the inner cylinders back and forth within the elastic limits of the control sample. Control and measuring devices provide a graphical recording of the test curve. This device design was adopted by the authors as a prototype, as it is closest in technical essence and the achievable technical result.

The device for determining the kinetics of curing of polymeric materials, in terms of its technical essence and the technical result achieved, is an essential feature of the device for simulating polymerization processes of polymeric materials, which is considered in the technical solution of the proposed invention.

The outer cylinder, in its technical essence and the technical result achieved, is an essential feature of the mold, which is considered in the technical solution of the proposed invention.

The internal cylinder, in its technical essence and the technical result achieved, is an essential feature of the measuring rod, which is considered in the technical solution of the proposed invention.

The power cam, in its technical essence and the technical result achieved, is an essential feature of the loading cam, which is considered in the technical solution of the proposed invention, a reciprocating rotational movement of the measuring rod at an angle of no more than 1°-2°. For newly developed polymeric materials with high viscoelastic properties, it is necessary to expand the measuring rod's rotation range to achieve reproducible test results. In this case, rotating the measuring rod in the polymer control sample by 1-2° is insufficient, requiring a wider range.

The technical problem that the proposed invention is aimed at solving is to provide a reciprocating rotational movement of the measuring rod to create shear deformations in a control sample made of a polymeric material in the range from 1° to 5°, which will provide the possibility of testing control samples of both existing and new types of polymeric materials in a wide range of their viscoelastic characteristics.

The technical result is achieved in that in a device for simulating polymerization processes of polymeric materials, it contains a thermostat with a stirrer, several pairs of molds with a coaxial measuring rod, placed in the thermostat and installed radially relative to the loading cam, a drive for the reciprocating rotation of the measuring rods, consisting of a loading cam mounted on the shaft of an electric drive and a command cam, levers that are rigidly connected at one end to the corresponding measuring rods, and at the other end, which has a roller, interact with the profile of the loading cam, an electrical circuit with control and measuring instruments, the difference being that the loading cam and the command cam are placed on a common base, with the help of which they are mounted on the shaft of the electric drive. In the loading cam, at the point where it is connected to the base by means of fastening elements, grooves are made which ensure the possibility of linear movement of the loading cam along the base and a change in the projection of its profile part relative to the axis of rotation.

The essence of the proposed invention is schematically explained by the drawings shown in Figures 1 and 2, where:

1 - thermostat;

2 - mold;

3 - measuring rod;

4 - lever;

5 - drive;

6 - cover;

7 - electric heater;

8 - stirrer;

9 - resistance thermometer;

10 - shaft;

11 - visual thermometer;

12 - level gauge;

13, 20 - electric drive;

14 - loading cam;

15 - screw;

16 - bearing housing;

17 - roller;

18 - cork;

19 - nut;

21 - command cam;

22 - glass;

23 - base;

24 - force transmitting screw;

25 - strain gauge;

26 - screw;

27 - stop;

28 - microswitch;

29 - rack;

30 - axis.

The device for simulating polymerization processes of polymeric materials consists of a thermostat 1, molds 2 placed in the thermostat, each of which contains a coaxial measuring rod 3 with a lever 4, a drive 5 for the reciprocating rotational movement of the measuring rods, and an electrical circuit (not shown).

Thermostat 1 is a cylindrical housing with a cover 6. The housing's interior is filled with a coolant. The thermostat is equipped with an electric heater 7, a stirrer 8, and a resistance thermometer 9. The thermostat also contains a visual thermometer 11 and a level gauge 12. Stirrer 8 is driven by an electric drive 13 and is used to uniformly heat the coolant.

On the cover 6 there are mounting places for installing molds 2, thermometers 9 and 11, stirrer 8 with electric drive 13, and in the central part - for drive 5.

To regulate the required conditions, thermostat 1 (temperature control) uses an electric heater 7 and a resistance thermometer 9 connected to an electronic temperature controller, which sets the coolant temperature to the desired value. The temperature controller supplies power to the electric heater and automatically maintains the coolant temperature within the specified limits. The current coolant temperature is monitored using the digital indicator of the secondary device.

The device contains five molds 2 with coaxial measuring rods 3. The molds are located radially relative to the center of the device and the loading cam 14 of the drive 5, and are vertically placed in the coolant and secured to the cover 6 with a screw 15. The mold is a cylindrical body, to the upper part of which a bearing housing 16 is attached by a threaded connection, in which the measuring rod 3 is fixed with its tail part. On the tail part of the measuring rod, a lever 4 is rigidly fixed with one end, and with the other end, which has a roller 17, the lever interacts with the profile of the loading cam 14 of the drive 5. The lower part of the body is provided with a removable bottom, made in the form of a sealed plug 18, which is pressed to the body with a nut 19. On the inner surface of the mold 2 and the measuring rod 3, longitudinal ribs are made, which are designed to prevent the rotation of the polymer material under study. To facilitate the unpressing of the mold when removing the cured polymer material from it, the inner surface of the mold and the measuring rod, which are in contact with the polymer material, are covered with an anti-adhesive compound before assembly.

Drive 5 is intended for sequentially imparting a reciprocating motion to measuring rods 3. Drive consists of electric drive 20, on shaft 10 of which loading cam 14 and command cam 21 are secured by means of base 23. Electric drive 20 is secured to cup 22, by means of which assembled drive 5 is mounted on cover 6. Loading cam 14 has a Z-shape design and can rotate on axis 30 in horizontal plane. Profile projection "B" is formed by the end surface of the lower horizontal platform of loading cam, which, during rotation, alternately interacts with lever 4 of measuring rod 3 of each mold. The upper horizontal surface of the loading cam interacts with the strain gauge 25 via the force-transmitting screw 24. Loading cam 14, where it is attached to the base 23 by screws 26, has slots that allow for its linear movement along the base 23 and, accordingly, for changing the offset of its profile section relative to the axis of rotation. The length of the slots in the loading cam allows for adjustment of the measuring rod's rotation within a range of 1° to 5°.

The command cam 21 performs command functions - it presses the spring-loaded stops 27 away from the levers 4 during their loading by the loading cam 14, and also stops the electric drive 20 after the loading cam has completed one full revolution, by acting with its profile part on the microswitch 28.

Strain gauge 25 is attached to cup 22 via post 29. It is used to measure the viscoelastic properties of the control sample. During operation, the strain gauge is subject to bending. The strain gauge is powered by a stabilized power supply. The supply voltage depends on the stiffness of the thermostatted control sample. The signal from the strain gauge is fed to the input of a potentiometer, which records the test curve.

The electrical circuit of the device ensures the creation of the necessary conditions in the thermostat 1, due to the electric heater 7 with the resistance thermometer 9 and the electronic temperature controller (not shown), the control of the electric drives 20 of the drive 5 and 13 of the stirrer 8, and the recording of the change in the viscoelastic characteristics of the control sample, by means of the strain gauge 25 and the potentiometer (not shown).

The polymerization simulation device operates as follows. The required temperature is created in thermostat 1 by heating the coolant with electric heater 7, a resistance thermometer 9, and a temperature controller. Once the coolant reaches the set temperature, electric heater 7 is switched off. Subsequently, the required coolant temperature is maintained in the thermostat by periodically switching on the electric heater. The current coolant temperature is monitored using the digital indicator of the secondary device. The temperature controller supplies power to electric heater 7 and automatically maintains the coolant temperature within the set limits.

To ensure uniform heating of the coolant, by turning on the electric drive 13 of the mixer 8, the circulation of the coolant in the housing is intensified.

A control sample of polymer material is placed in molds 2 and assembled, with measuring rod 3 installed. Depending on the viscoelastic properties of the polymer material, loading cam 14 is moved along base 23 by loosening screws 26, thereby setting the required extension of its profile relative to the axis of rotation. The assembled molds are installed in seats on cover 6 and secured with screws 15. Levers 4 are mounted on the measuring rod shanks. The molds containing the control sample are heated for the time specified in the process documentation.

After this, electric drive 20 is activated, and loading cam 14 is rotated. Its profile projection "B" sequentially acts on each lever 4 of all five molds. At this point, measuring rod 3 in each mold rotates by an angle within the elastic limits of the control specimen, thereby creating a shear strain in it. Loading cam 14, via force-transmitting screw 24, creates a bending moment in strain gauge 25, which causes a change in the resistance of the strain gauges of the strain gauge bridge. This change is recorded on the potentiometer's chart as peaks.

The loading cam 14, having completed one full revolution, stops due to the fact that the command cam 21 presses the microswitch 28, and turns off the electric drive 20. The turning on of the electric drive 20, and, accordingly, the rotation of the loading cam 14 is repeated the required number of times, at intervals determined by the technological documentation.

The peak heights on the potentiometer's graph increase as the control sample polymerizes, and once the polymerization process is complete, the peak heights stabilize and are recorded as equal. This indicates the end of the polymerization process.

Next, turn off electric heater 7 and loosen screw 15. Remove lever 4 from measuring rod 3, and remove molds 2 containing the control sample from their mountings in cover 6 and press them out. The polymerization simulation device is ready for a new cycle. The device then repeats its operating cycle.

A device for simulating polymerization processes in polymeric materials, thanks to the ability to adjust the load cam's profile extension relative to its axis of rotation, enables reciprocating rotation of the measuring rod to create shear deformations in a polymer control sample, ranging from 1 to 5°. This enables testing of control samples of both existing and new types of polymeric materials across a wide range of their viscoelastic properties.

Testing of the proposed invention in pilot-industrial conditions at JSC NIIPM confirmed its effectiveness and operability.

Claims (1)

A device for simulating polymerization processes of polymeric materials, comprising a thermostat with a stirrer, several pairs of molds with a coaxial measuring rod, placed in the thermostat and mounted radially relative to a loading cam, a drive for the reciprocating rotation of the measuring rods, consisting of a loading cam mounted on the shaft of an electric drive and a command cam, levers that are rigidly connected at one end to the corresponding measuring rods, and at the other end, which has a roller, interact with the profile of the loading cam, an electrical circuit with control and measuring instruments, characterized in that the loading cam and the command cam are placed on a common base, with the help of which they are mounted on the shaft of the electric drive, wherein in the loading cam at the place of its connection by means of fastening elements with the base, grooves are made, which ensure the possibility of linear movement of the loading cam along the base, and a change in the extension of its profile part relative to the axis of rotation.