CS273697B1 - Method of polymeric substances' treatable characteristics determination and device for realization of this method - Google Patents

Abstract

The design concerns the method of determination of processing characteristics of polymeric substances, especially the moment of force and rise in temperature when kneading in the chamber kneader and synchronous determination of optimal black distribution in the process of mixing. The principle of the design are the chamber kneaders (6,7) with a different size of rotors, which are equipped with the dynamometer (1) and tachometer (2), which are connected via the mechanical transmission with the scale (3) and registration of the moment of force. The chamber kneaders (6, 7) are further equipped with the thermostat (8), cooling system (9) and air blower (11).<IMAGE>

Description

(57) The present invention relates to a method for determining the processing characteristics of polymeric substances, in particular the moment of force e e heat build-up in kneading. This includes determining the optimum distribution of the carbon black during mixing. The essence of the device is a chamber kneader: (6, 7) and different rotor shapes, equipped with a dynamometer (1) and a tachometer (2) connected by mechanical transmission to the scale (3) and recording of the torque force. The chamber # mixers (6, 7) are supplemented by a thermostat (8), a cooling system (9) and an air blower (11).

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CS 273697 Bl

(13) Bl (51) Int. Cl. ⁵ G01N 7/16

The present invention relates to a method and a device for determining the processing characteristics of polymeric substances.

To date, methods of analyzing the number of polymeric substances, such as determining viscosity and with a rotational viscometer, are known. The essence of this test is to determine the torque of the rotor and the chamber filled with the test material, such as rubber or carbon black, prepared from calendered foil. The disc of the test material ee is threaded onto the rotor shaft and the other side ee is placed on the other. The rotor with the test piece (disc) is inserted into the instrument chamber and the device is closed. The device is heated and the torque is determined 4 to 15 minutes after the rotor is started. Another method is to determine the processability of the polymeric substance in a laboratory kneader. The essence of this test is to determine the engine power of two profiled rotors in a closed space and the temperature that the kneaded mass develops over time. Again, the material to be tested is, for example, rubber or a carbon black mixture 8 resulting in a weight of 70 to 75% of the useful volume of the enclosure. The workability index of the polymer substance as determined by its recalendering or the second maximum power input of the engine is evaluated.

Another method is to determine the processing characteristics of polymeric substances in a universal kneading machine. The essence of the test is to determine the resistance of the inserted material subjected to shear stress and heat evolution for a specified kneading time between standard profiled rotors in an enclosed space. An amount of polymeric substance is introduced into the heated space to fill 70 to 75% of the useful volume of the closed space after all the additives have been added. The moment of force (relative viscosity) and the temperature level of the kneaded mass ee are read after the selected mixing time. The optimum mixing time of the carbon black is determined experimentally, samples are taken during mixing, and the distribution of the carbon black particles in the rubber is evaluated by microcomputer processing. The vulcanization system is mixed in a calender in a mill calender.

A disadvantage of these methods of determining the processability of polymeric substances is the laboriousness, time-consuming and inaccurate measurements. There is also a large consumption of test material.

These disadvantages are eliminated by a method of determining the processing characteristics of the polymer compounds according to the invention whose principle consists in that the material without pre-treatment are placed in a heated chamber internal mixer in a quantity which completely fills the useful space and kneaded ee at a rotor speed of 30 to 120 min ^"1 after the torque and temperature of the kneaded polymer are read off after 2 to 12 minutes.

This polymeric substance is ee inserted into another, cooled kneader, continued kneading, soot additives are added and ee continuously measured the electrical conductivity of the mixture, decreasing from the second maximum electrical conductivity dependence, the rotor speed is reduced to a minimum, ee cooling and read the moment of force, the temperature of the mixture and the time of optimal distribution of the carbon black.

After cooling to a mixture temperature of 23 to 70 degrees Celsius, vulcanizing additives are introduced to fully utilize the chamber mixer space, rotors speed and increase to 30 to 120 min ^-1 , the mixture is relieved, the ee stops and the mixer opens. After the specified period of time, a test specimen was prepared for the vulcameter. The safety and the mixture, the rate and the optimum vulcanization time were measured under selected temperature conditions.

The essence of the device for performing the method of determining the processing characteristics of polymeric substances is that the dynamometer is connected with a thermostat and a mechanical transmission by a scale of 0 by recording the torque and by means of a clutch and a chamber mixer. The two-part chamber kneader is resiliently connected by a β thermostat, a cooling water inlet and nozzles are directed towards it, resiliently coupled to an air blower;

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CS 273697 Bl

The advantages of the method for determining the processing characteristics according to the invention are, in particular, that the method provides technical data which could not be used in practice in terms of length and complexity. Compared to the current method, the total time of transmission of all information is reduced by a factor of 10, and more data is obtained according to this method.

Greater effect can be achieved by coupling two chamber kneaders, resulting in the possibility of cooling off the work position and working with rubber in one of the two kneaders. This way of adjusting the device allows to work with different designs of profiled rotors.

For polymeric materials, a triangular shape of the rotors can be used, which ensures spreading on the walls of the chamber, and thus the measured torque reading better reflects the relative viscosity of the kneaded mass.

For mixing the base of the carbon black mixture on a laboratory scale, a droplet-shaped chamber mixer is preferably used which essentially corresponds to the large chamber mixer installed in the factory. Rotors of this shape, moving in the enclosure of the kneader, provide grinding and crushing of the mass that is pressed against the side wall of the kneader; kneading the material which is rolled, bent, shredded and spread against the wall of the kneader with periodic release; the material being punched, part of which is torn from the whole e drawn into the material at another location and finally overlapping the material, a part of which is pushed into the center of the rotors from both sides.

An apparatus for measuring the processing characteristics of polymeric materials is shown in the accompanying drawings, in which Fig. 1 shows the overall configuration of a tandem test apparatus of two end mixers, and Fig. 2 shows a schematic arrangement of a chamber mixer in an operating position.

The test apparatus according to FIG. 1 consists of a dynamometer 1 with the possibility of selecting the measuring range which is connected to the tachometer 2 and the mechanical transmission 6 then to the scale 4; to which the set measuring range can be read. The force torque registration is based on the principle of sensing the resistance of the processed mass during kneading. Via the coupling 15, it is possible to connect the chamber mixer 6 and the triangular-shaped rotors and the chamber mixer 7 with the drop-shaped rotors with wings. The chamber mixer 6 is resiliently connected to a thermostat 8 which maintains an optimum working temperature within the chamber mixer 6. The chamber mixer 7 is equipped with a cooling system 9 that utilizes water flow through the two halves of the chamber cavities with subsequent cooling of the working temperature. When using chamber mixers 6, 7 with one kind of rotors, the thermostat 8 comprises water and one flexible connection then the control taps.

The chamber mixer 6 is cooled in a non-working position by a nozzle 10 resiliently connected to the blower 11. The second cooling nozzle 12 is cooled by a chamber mixer J in the working position (after mixing the soot). The chamber kneader 6, 6 is supported on a guide substrate 13 which allows one to be in a non-working position while the other is in a working position. The position of the two chamber mixers 6, 2 in this position is ensured by their firm connection and by means of pins 14.

The displacement of the chamber mixers 6, 6 is carried out mechanically or hydraulically.

The assembly of the two hydraulic mixers 6, J according to FIG. 2 is carried out in such a way that each chamber mixer 6, 7 is two-piece. The first clutch part 15 comprises rotors. The second part 16 comprises chambers 6 and 7 and slips on. This movement is effected by means of screws 17. The second part 16 has a filling opening provided with a slide 18 and a built-in sensor 19 for sensing the temperature and measuring the electrical conductivity. This sensor 19 is connected to the recording apparatus 20, 21. The second part 16 also has a threaded protrusion 26 of the backing plate 22 mounted on the first part 15 which serves for mechanical or hydraulic separation from the first part 15 by means of screws 17.

CS 273697 Bl

The chamber kneaders 6 and 7 are disposed on a guide pad 11 inserted in a guide groove 24 and have a flow cooling system 26. The chamber kneader 7 may, as mentioned, have different rotor shapes. If one is triangular in shape and the other is teardrop, this tandem performs the task of measuring the polymer viscosity and the carbon black mixing process. If it is a tandem chamber mixer with the same rotors, then one performs a measuring operation, the other cools and cleans.

A specific embodiment of the invention is set forth in the following examples.

Example 1

Using one chamber kneader 6, the procedure is as follows:

(a) Processing characteristics of styrene-butadiene rubber.

75 g of styrene-butadiene rubber, taken from the bale at the end of the production line, was loaded into a heated chamber kneader 6 with droplet-shaped rotors at a measuring range of 50 Km and a rotor speed of 80 min. After 30 seconds, the beam was closed with a load of, for example, 3 kg and the torque (Hm) and heat evolution (° C) data were recorded as a function of the kneading time. Stirring was complete at 4 minutes. The temperature rose to about 125 degrees Celsius. The viscosity range of 42-54 ° Mooney corresponded to a narrow interval of force torque results.

(b) Processing characteristics of the styrene-butadiene rubber base

1. 48.7 g of styrene-butadiene rubber, 1.5 g of zinc white, 0.5 g of stearic acid and 24.3 g of channel carbon black were charged to a cooled kneader at 30 degrees Celsius under the same conditions of a). After 60 seconds, the bar was closed with a load of, for example, 5 kg and the data according to a) and, in addition, the electrical conductivity (mS) were recorded. The time to reach the second maximum electrical conductivity defined the mixing process.

After opening the chamber kneader using the clamping screws, it was cleaned of soot and tempered for the next rubber test.

The results of the optimum mixing time of the carbon black (S) and the heat development (T) served to compare the quality of the styrene-butadiene rubber:

Styrene Butadiene With Rubber

Evaluation Sample A Sample B

2.5

2.5

133 normal manifestation

140 higher heat development by 6,8%

2. A mixture of rubbers was inserted under the same conditions as in 1.:

Natural rubber 30 parts by weight, polyisoprene rubber 10 parts by weight and polybutadiene rubber 10 parts by weight in a common weight of 48.7 g.

The results of the optimum soot time (S), the heat evolution at the optimum soot time (T1) and after 8 minutes of stirring (T2) served to compare the soot wrapping ability:

CS 273697 Bl

Rubber WITH TI Styrenbutadienový 2.5 133 Smea according to 2. 7.0 142

T2 Rating

150 normal expression

145 extended time of optimum soot distribution by 4.5 minutes (280%)

Example 2

When using two chamber mixers 6, 7, the procedure is as follows:

(a) Processing characteristics of styrene-butadiene rubber.

Under the same conditions of Example 1, with changes to the use of triangular rotors, a measuring range of 20 Nm and a weighing of 25 g of styrene-butadiene rubber (for styrene-butadiene-oil adjusted Jan 15 Nm).

The resulting moment of force (relative viscosity), heat evolution and plasticization rate were supplemented by the index of heat evolution (° C) and moment of force (Nm).

Calculation of plasticization rate (Vp):

_{in B} .JL ·. ”. ^B - Nm / sec P t where A = highest torque at the beginning of measurement, Nm B and force torque after 4 min (240 sec) of measurement, Nm and Sas between force torque data, sec

Calculation of the relative viscosity index (I _v ):

where A measured temperature after 4 minutes of measurement, ° C B * initial measurement temperature C = relative viscosity, Nm

They used the same viscosity values (48 ° Mooney) to assess the difference in quality of two samples:

Styrenbutad ien rubber ^H p T ’P ^T v Evaluation sample A 2.2 42 0.06 19.1 normal manifestation sample B 1.7 50 0.08 29.4 worse to process

CS 273697 Bl

with T in P AND in Evaluation difference A - B,% -22.7 +19 +33.3 +53.9 differences exceeded 10%, the viscosity index determined the degree of variation. Used to assess viscosity (48 ° Mooney) difference in speech quality two kinds of rubber of the same Styrene-butadiene rubber ^M s T ^v p Evaluation (a) basic 2.2 42 0.06 19.1 normal manifestation (b) oil-adjusted 2.4 30 0.04 12.5 normal manifestation difference a - b,% +9.1 -28.6 -33.3 -34.5 moment of force does not exceed

Chill 10%, sample b showed lower heat development, less plasticized, better processing quality is 34.5%

(b) Processing characteristics of the styrene-butadiene rubber base

Under the same conditions with the changes that the measurement took place immediately after moving the chamber mixer 7 to the working position, ie without waiting for cooling, and the cleaning after discharge of the mixture may not have been as thorough as the next measurement was again with soot.

Example 3

Another possibility of practical application of the present invention is the methodology of shredding polymeric materials such as rubbers

(a) in the manufacture of styrene-butadiene rubber.

The shredding of the rubber is carried out according to the relative viscosity (moment of force Nm). At the beginning of the palletizing, a test sample is taken for measurement in the treated machine. The first information is available after the second pallet has been produced. It is possible to provide the relative viscosity with each pallet produced,

Until the production of about 10 pallets, processability and vulcanization data are available.

(b) in the processing of styrene-butadiene rubber.

It allows the stock to be divided according to the relative viscosity values and limits the frequency of measurement by the input control,

Improved viscosity on the pallet allows to improve the organization of work in preparation <· *

CS 273697 B1 materials of two different viscosities.

A further advantage of the present invention is the device of the described measuring device into the working line after being completed with a small hydraulic press with electrically heated trays, a punching rotary press and circular knives and a vulcameter with a linear chart recorder.

By setting up the working line, the viscosity of the polymer and the heat evolution, the viscosity of the polymer / carbon black mixture, the heat evolution and the optimum distribution of the carbon black can be determined in a very short time.

Claims (5)

SUBJECT OF THE INVENTION A method for determining the processing characteristics of polymeric materials, wherein ae measures the torque of force and temperature rise when kneaded by two rotors under specified conditions in a confined space filled with a polymeric material sample, for example rubber or carbon black, characterized in into a heated chamber mixer in an amount that fills the useful space and rotates at a rotational speed of 30 to 120 min ** ¹ for 2 to 12 min, after kneading the moment of force and the temperature of the kneaded polymer substance are read, 2. A method according to claim 1, characterized in that after subtracting the moment of force and temperature, the polymeric substance is introduced into another cooled kneader, the kneading is continued, the carbon black additives are added while measuring the electrical conductivity of the mixture and reaching a decrease from the second maximum. As a function of the electrical conductivity, the rotational speed of the rotors is reduced to a minimum, carried out and refined, and the torque of the force, the temperature of the mixture and the optimum soot distribution time are read. 3. The method of claim 2, wherein SB that after the optimum distribution of the carbon black and the mixture temperature in the range of 23-70 ° C is placed curatives, tilt rotors was raised to 30 to 120 min ^1, and by stirring the mixture at the end the moment of force and the temperature of the kneaded polymer substance are subtracted. Device for carrying out the method according to Claims 1, 2 and 3 *, characterized in that the dynamometer (1) is connected to a speedometer (2) and a mechanical transmission with a scale (3) and torque recording and by means of a clutch (5) with a triangular rotor chamber kneader (6) and a droplet rotor chamber kneader (7) with a triangular rotor chamber kneader (6). (9) and both chamber mixers (6, 7) are adapted to air cooling by means of a blower (11) and nozzles (10, 12). 5. Device according to claim 4, characterized in that the two chamber mixers (6, 7) are supported on a guide support (13) adapted to be fixedly connected in the working part by means of pins (14).