1、UDC 678.074 : 620.1.05 : 532.137 DEUTSCHE NORM May 1991 Determination of Mooney viscosity of rubber Test apparatus - - DIN 53 523 Part 2 Prfung von Kautschuk und Elastomeren: Prfung mit dem Scherscheiben- Viskosimeter nach Mooney; Anforderungen an das Gert Diameter Supersedes November 1976 edition.
2、Thicknesslheight In keeping with current practice in standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal marker. 38,l k0.03 Shearing disc of large rotor 1) See Explanatory notes for connection with International Standard IS
3、0 289 : 1985 published by the International Organiza- tion for Standardization (ISO). 5,s 20,03 Dimensions in rnm For general tolerances, accuracy grade m as specified in DIN 7168 shall apply. Rotor shaft 1 Scope and field of application This standard describes the shearing disc viscometer which is
4、used to determine the Mooney viscosity of rubber, or the Mooney viscosity and the time to incipient cure (Mooney scorch) of compounded rubber. For the purposes of this test, the test pieces may be made of natural andlor synthetic rubber. Part 1 of this standard deals with sample preparation, Parts 3
5、 and 4 giving specifications for the measurement of Mooney viscosity and Mooney scorch, respectively. 10 21 - 2 Principle The Mooney viscometer consists of a temperature-con- trolled die cavity with a flat, cylindrical chamber in which a rotor turns a flat cylindrical shearing disc. When a test piec
6、e is placed in the cavity, a torque is produced which acts on the rotor shaft. The Mooney viscosity or Mooney scorch of the test piece can then be assessed on the basis of the change in torque over time, expressed in Mooney units. 3 Apparatus The apparatus incorporates the following components: a) t
7、wo dies to form a cylindrical cavity, and rotor; b) closing devices; c) temperature measuring device; d) temperature control circuit; Shearing disc I I Die cavity I 50,9 +O,I I 10,95+071 I 30,48 k0.03 554 20.03 I Shearing disc of small rotor 1) I Grooved as shown in figure 2 Grooved as shown in figu
8、re 3 m O +I 4 QI VI f ml i y/ TM test circuit temperature sensor / TR control circuit termerature sensor Rotoishaft Y DiehLder Die cavity 0 50,9W Clamping plate Figure 1. Diagram of a typical Mooney viscometer Continued on pages 2 to 5 Jth Verlag GmbH. Berlin, has the exclusive right of sale for Ger
9、man Standards DIN-Normen). DIN 53 523 Part 2 Engl. Price group 6 Sales No.0106 93 Page 2 DIN 53 523 Part 2 4.1.2 Grooving of die surfaces 4.1.2.1 Die with rectangular-section grooves The top and bottom inside surfaces of the dies shall be grooved as shown in figure 2, the cylindrical wall surface fo
10、rmed by the die holder being grooved as shown in figure 3 c). These grooves serve to prevent the test piece slipping inside the cavity. Note. The configuration of the die cavity shown in figure 1 (two dies and a die holder) is intended to facilitate machining of the grooves and is not mandatory. Oth
11、er configurations are permitted. 0,8W c) o m 0- +I Groove edges to be rounded to 0.1 mm or less. Figure 2. Grooving of top and bottom die surfaces and of rotor end faces Groove edges to be rounded to 0,l mm or less. 60 grooves 75 grooves 1 O0 grooves around around around perimeter perimeter perimete
12、r a) small rotor b) large rotor c) dies Figure 3. Grooving of rotor surface and die walls 4.1.2.2 Dies with radial V-grooves Instead of a cavity formed as indicated in subclause 4.1.2.1, dies with radial grooves, as shown in figure 4, may be used, each of the dies being made as a single piece (which
13、 pre- cludes grooving of the cavity wall). Note. Use of single-piece dies to form the die cavity gives a better heat transfer from clamping plate to test piece, and correspondingly less time is required to bring the latter to test temperature. I 50.9 20.1 . Figure 4. Die with radial V-grooves 4.1.3
14、Rotor The top and bottom surface of the shearing disc shall be grooved as shown in figure 2 and along its perimeter as shown in figure 3 a) or figure 3 b). The rotor shaft shall be made of hardened steel. It shall be positioned in the cavity so that the clearance between the top of the disc and that
15、 of the cavity, and that between the underside of the disc and the bottom of the cavity do not differ by more than 0,25 mm. The rotor shall be fastened to a hollow shaft so as to rotate with it. the shaft not bearing on the wall of the cavity. The run-out of the rotor while turning shall not exceed
16、0,l rnm. 4.1.4 Sealing of rotor shat The play of the rotor shaft in the die bore shall be small enough to prevent the test piece material penetrating be- tween shaft and bore. To this effect, a sealing device (e.g. in the form of a grommet) made of rubber, plastic or some other material may be provi
17、ded which does not generate a frictional torque exceeding 3 Mooney units (cf. subclause 4.6.2). Note. The type of seal shown in figure 1 is not mandatory; O-rings may also be used. 4.2. Die closing device 4.2.1 Closure device drive The die closing device shall be operated with a pneumatic, hydraulic
18、 or mechanical drive. 4.2.2 Parallelism of mating surfaces The die mating surfaces shall be parallel after closure. To check this, a sheet of soft tissue paper not thicker than 0,05 mrn shall be placed between the surfaces. Closure shall produce a uniform and continuous impression in the paper, a no
19、n-uniform or discontinuous pattern indicating incorrect adjustment of die closure or distortion of the dies. This may result in leakage and erroneous results. DIN 53523 Part 2 Page 3 4.2.3 Closing force It shall be possible for the dies to be closed with a force of (11,5 k 0.5) kN, this force being
20、maintained throughout the test. For rubber of high viscosity, a higher force may be applied for not more than ten seconds before the rotor is started. 4.3 Temperature measurement 4.3.1 Temperature sensor and indicator A temperature sensor (TM; see figure 1) shall be fitted in each of the two dies. T
21、he best possible heat contact be- tween the sensors (measuring resistors, thermocouples) and the working surfaces of the dies shall be ensured, with air gaps and other thermal resistances being eliminated. The sensor axes shall be not more than 5mm away from the working surfaces of the dies and 15 t
22、o 20 mm from the rotor axis. The steady-state temperatures measured at these points (with the rotor in place and the cavity closed, but without a test piece) shall count as the test temperatures. The sensor shall be connected to an electrical temperature indicator. Depending on the field of applicat
23、ion of the vis- cometer, the indicating instrument may be designed for measurements in the ranges 95 to 145 OC or 95 to 200 OC. Indicators which permit switcfiing between measuring rang- es may also be employed. Whatever indicating instrument is used, its resolution shall enable temperature differen
24、ces of 0,25 OC to be read reliably. 4.3.2 Calibration of temperature measuring system For calibration purposes, the temperature measuring de- vices must be connected to the indicating instruments. They shall be removed from their mountings and immersed in a bath of known temperature. Means shall be
25、provided for adjusting the temperature of the bath to the standard labo- ratory temperatures of 100,120,130 and 140 OC with the aid of verified enclosed-scale mercury thermometers, due allowance being made for the stem correction. The temper- ature measuring device shall be capable of indicating tem
26、- perature to an accuracy of 0,25 OC. A corresponding repro- ducibility of the measured values shall be guaranteed by the manufacturer. If this is not the case, appropriate corrections shall be made. 4.3.3 Determination of test piece temperature To check whether the mean temperature of the test piec
27、e is at the test temperature at the specified test time (four or eight minutes), the dies shall be so designed that two measuring probes (one for each die member) can be inserted into the test piece (see figure 5). In a preliminary test with the test piece to be measured, the rotor shall be stopped
28、after running for 3.5 or 73 minutes. After the rotor has stopped, the two probes shall be inserted and the temperature measured after four and eight minutes, respectively. Neither of the two temperatures thus deter- mined shall lie more than 2OC below the specified test tem- perature (see subclause
29、4.3.1). 4.4 Temperature control circuits Each die shall have its own temperature control circuit con- sisting of a temperature sensor, controller, actuator and heater. The temperature sensors of the control circuits may be fitted in the same way as those of the temperature measuring device (see subc
30、lause 4.3.1 and figure l), the controllers permitting adjustment of the test temperature in increments of not more than 0.2 OC. The heaters shall be so arranged that the temperature in the test piece is as uniform as possible. Both control circuits shall be adjusted so that the test temperature is r
31、eached again 1.5 to 3 minutes after a test piece at a temperature of about 20 OC has been introduced into the cavity which, with the rotor in place and closed, has previously been main- tained in thermal equilibrium. The temperatures as recorded at the sensors shall be reached to within I0,5 OC with
32、out overshoot. 4.5 Rotor drive The rotor shall be driven by an electric motor in series with a reducing gear. In the tests specified in DIN 53523 Part 3 and Part 4, its speed shall be (2 5z 0,02) min-. 4.6 Torquemeter 4.6.1 Requirements relating to torque measurement The rotor torque shall be indica
33、ted in Mooney units on a linear scale or recorded by a chart recorder (a torque of 8,3Nm applied to the rotor shaft being equivalent to 100 Mooney units). The scale shall permit 0,5 Mooney units to be read reliably. 4.6.2 Calibration of torquemeter The torquemeter shall be calibrated using a rotor w
34、ith a pulley in place of the shearing disc. Various torques are pro- duced with the pulley by allowing a steel wire, which is run around rollers mounted on ball bearings and loaded with weights, to act at the pulley perimeter. The nominal wire diameter shall be 0,45 mm (e.g. DIN 2078 wire having a n
35、ominal diameter of 0,45 mm and a nominal strength of 1370 N/mm2). To enable the frictional torque between the shaft of the rotor and the seal in the lower die to be deter- mined (see subclause 4.1.4), the rotor shall not be in contact with the seal during calibration. Accordingly, the shaft diameter
36、 of the rotor must either be sufficiently small where it is passed through the seal or, alternatively, the seal shall be removed before the rotor is inserted. Before calibration is started, the temperature in the die cav- ity shall be adjusted to the test temperature. The rotor drive shall be switch
37、ed on temporarily for each reading of the torquemeter so as to avoid measurement errors due to static friction in the bearings of the rollers and the rotor drive. The meter shall be adjusted to give a zero reading, with the rotor unloaded and (100 f 0,5) Mooney units at a torque of 8,3 Nm. It is rec
38、ommended that the linearity of the reading be checked from time to time over at least four steps (50, 100, 150 and 200 Mooney units) by applying corresponding torques to the rotor. The variations in the torque reading with the rotor unloaded and loaded shall not exceed 0,5 Mooney units over a period
39、 of 30 seconds. After calibration, the rotor shaft seal shall be replaced if it has been removed and the large or small rotor with the dimensions specified in subclause 4.1.1 shall be reinstalled. When the drive is switched on, a torque of not more than 3 Mooney units shall be produced (see subclaus
40、e 4.1.4). The torque reading thus obtained shall be corrected by setting to zero before the test piece is examined. 5 Auxiliary equipment 5.1 Timer In the tests specified in DIN 53 523 Parts 3 and 4, the rotor is not to be actuated until one minute after the test piece has been inserted and the cavi
41、ty closed, in order to prevent excessive loading of the equipment. It is therefore advisable to incorporate a timer which starts up automatically when the distance between the upper and lower dies drops below 10 mm during closure. 5.2 Cutter To prepare the test pieces specified in DIN 53 523 Part 3,
42、 a vertical cutter shall be used which enables discs and rings to be produced from compounded rubber. Page 4 DIN 53 523 Part 2 A F 6-6 Measuring I probe inserted Insertion depth A-A Stopper and guide Stopper connected to measuring probe connected to vi Figure 5. Insertable measuring probes of the te
43、st is to investigate the Mooney viscosity in accord- ance with DIN 53523 Part 3 or the Mooney scorch in accordance with DIN 53 523 Part 4. DIN 53 523 Part 2 Page 5 Standards referred to DIN 2078 Steel wire for wire ropes DIN 7168 General tolerances for linear and angular dimensions and geometrical t
44、olerances (not to be used for new designs) DIN 53 523 Part 1 Determination of Mooney viscosity of rubber; sample preparation DIN 53 523 Part 3 Determination of Mooney viscosity of rubber: determination of viscosity DIN 53 523 Part 4 Determination of Mooney viscosity of rubber; determination of Moone
45、y scorch IS0 289 : 1985 Determination of Mooney viscosity of rubber Previous editions DIN 53 523: 09.60; DIN 53 523 Part 2: 11.76. Amendments The November 1976 edition of this standard has been amended to bring it into line with IS0 289 : 1985. Explanatory notes This standard has been prepared by Te
46、chnical Committee 435 Viskoelasfische Eigenschaften von Elastomeren of the Normen- ausschu Materialprfung (Materials Testing Standards Committee). The devision of the standard into four Parts has been retained, but the content is the same as that of International Standard IS0 289 : 1985. In particul
47、ar, the dimensions of the appa- ratus and other numerical specifications and tolerances are identical. However, most of the more stringent requirements included in the previous version of the present standard with respect to the temperature control circuits have been retained, and the test temperatu
48、re (as measured by the built-in sensors in the dies) must here be stabilized again to within k 0,5 OC of the test temperature within 1,5 to 3 minutes of a test piece at 20 OC being introduced. The IS0 Standard only specifies a five minute maximum for the return to the test temperature. The variation
49、 of temperature with time is an important factor in the reproducibility and any apparatus used shall only exhibit minimum differences in this respect. This variation is also controlled by checking the test piece temperature as specified in subclause 4.3.3. For this purpose, measuring probes are inserted into the test piece itself and its internal temperature is measured after a specified time. This temperature shall be lie more than 2 OC below the test temperature. This check is also included in the IS0 Standard. It is intended to reduce the currently permitted deviation of 2
