1、UDC 678.074 : 620.1 : 532.137 DEUTSCHE NORMEN November 1971 Testing of Rubber and Elastomers TESTING WITH THE MOONEY SHEARING DISK VISCOMETER Determining the Mooney Viscosity m 53 523 Part 3 Prfung von Kautschuk und Elastomeren; Prfung mit dem Scherscheiben- Viskosimeter nach Mooney; Bestimmung der
2、Viskositt nach Nooney For connection with the Recommandation ISO/R 289-1963 published by the International Organization for Standardization (ISO), see Explanations in DIN 53 523 Part 1. 1 This Standard describes the method for determining the viscosity in Mooney units of natural and synthetic rubber
3、s, unvulcanized mixtures based on natural and synthetic rubber and reclaimed rubber by means of the shearing viscometer. Purpose and range of application The Mooney Viscosity values obtained only provide, with certain reserva- tions, an indication of the relative molecular weight of the rubbers. Not
4、e: For example, in the case of butyl rubber with a rising relative molecular weight, the Mooney viscosity initially rises to an upper limit value of -80 at a temperature of 100 OC and a large rotor speed of 2 min 2, followed by a drop to much lower values. A better relationship between the viscosity
5、 and relative molecular weight is obtained in the case of such high molecular weight rubbers if the rotor speed is reduced or the temperature is increased. 2 Definition During the test, the torque necessary under tbe prescribed conditions for taking a metal disk in a rubber-filled cylindrical chambe
6、r is determined. A numerical value proportional to the torque (Mooney unit) serves as a measure for the Mooney viscosity of the rubber. 3 Sample preparation and producing the specimens 3.1 Sample production See DIN 53 523 Part 1 3.2 Sample pretreatment See DIN 53 523 Part 1 No te : The viscosity is
7、influenced by sample production and sample pretreatment, so that the stipulations for the individual rubbers are to be carefully adhered to. For Explanantions, see DIN 53 523 Part 1. Continued on pages 2 to 4 Soiesaie rights of German Standards (DIN-Normen) are with Beuth Verlag GrnbH, Bedin 30 04.8
8、1 DIN 53523 Teil 3 engl. Preisgr. Vertr.-Nr. O104 Page 2 DIN 53 523 Part 3 3.3 Specimens The specimen stamped out by means of a cutting press comprises a centrally perforated disk and an unperforated disk of the material under investigation. The specimen diameter should be 45 to 60 mm and the thickn
9、ess 8 mm. The hole should be about 1 mm larger than the rotor shaft diameter. If from the outset, the specimens do not have adequate thickness sufficient disks must be cut out to provide an 8 to 10 mm thick disk layer when they are superimposed. The total volume of the two-part testpiece should be m
10、in 25 cm3. 4 Test apparatus See DIN 53 523 Part 2 5 Procedure 5.1 Test temperature The test is performed at 100 OC, unless another temperature is agreed. 5.2 Testing process Generally, the large rotor is used but, if necessary, the small rotor can be used with high viscosity values. With the test ch
11、amber closed, the latter and the rotor are heated to the testing temperature and it is then necessary to wait until thermal equilibrium is established. Note: Unlike in ISO/R 289 and in particular for tests in continuous operation, the following procedure is used. If there are spare rotors, they can
12、be preheated outside the test chamber, e .g. in heating cabinets to the prescribed test temperature. The test chamber is opened, the rotor shaft is passed through the hole in the disk sample, and in this way the rotor is inserted in the viscosimeter. The other unperforated disk sample is placed cent
13、rally on the rotor and the chamber is closed as rapidly as possible. At the end of the closing process, the sample is preheated with the rotor inoperative for the prescribed time, but for at least 1 minute. The preheating time is noted. Note: The temperature gradient and the heat transfer rate diffe
14、r between the individual viscometers. This is particularly the case if different heating systems are used. It is therefore to be expected if the values obtained with different viscosimeters can be more readily compared if the specimens have assumed the test temperature. Normally, this state is reach
15、ed after about 10 minutes testing. At the end of the preheating time, the drive is switched on and the rotor operates at a speed of 2 min- f 0.02 min-. On switching on the rotor, the time measurement starts and continues until the prescribed test period is at an end, this being generally 4 minutes.
16、The measuring results of tests with small and large rotors are not identical. However, they lead to the same grading of the results in the case of comparative measurements on rubbers or mixtures. DIN 53 523 Part 3 Page 3 6 Evaluation of the test results 6.1 Determining the Mooney viscosity If the Mo
17、oney viscosity is not continuously recorded in graph form, the reading and the scale are to be continuously read off at 30 second intervals. The lowest value in the time interval immediately preceding the requisite reading time is read off to within 0.5 units and constitutes the Mooney viscosity. In
18、 arbitration cases, the readings are to be made in 5 second intervals 1 minute before and 1 minute after the prescribed time. If periodic fluctuations occur, a smoothed curve is to be drawn through the lowest measured points. If these fluctuations are not readily apparent, a curve is formed through
19、all the measured points. The Mooney viscosity is the point at which the viscosity curve intersects the prescribed time value. 6.2 The measuring results are given by means of letters and numbers in the following manner : Representing the measuring results (code designation) VML or MS (X + Y) 2 M Moon
20、ey viscosity L Standard rotor (large rotor) S Small rotor V X Preheating time parameter in minutes - normal case: 1 min Y 2 Viscosity parameter in Mooney units Test time parameter in minute - normal case: 4 minutes Test temperature parameter in OC - normal case: 100 OC Example: 50 ml (1 + 4) 100 OC
21、means that the Mooney viscosity of the tested material is 50 measured with the standard rotor, with a preheating time of 1 minute, a test time of 4 minutes and a test temperature of 100 oc. 7 Test report Whilst referring to this Standard, the test report must indicate: Designation of the sample Samp
22、le preparation Apparatus type and closing device Measuring result in short form according to Sections 6.1 and 6.2 Deviations from this Standard 8 Testing errors The standard deviation in repeat mesurements (one observer, one apparatus, one uniform sample) is 0.5 units. Differences in the sample prep
23、aration on average lead to standard deviations of 1 to 2 Mooney units. Note : The reference scatter range (different testing stations) can lead to even higher scattering in the measuring results. Part of the variation in the test results between different laboratories is due to the different way in
24、which the samples are prepared and part is due to the errors in checking and regulating the viscosimeter. Page 4 DIN 53 523 Part 3 Further Standards DIN 53 523 Part 1 Testing of rubber and elastomers: testing with the Mooney shearing disk viscometer; preparation of samples DIN 53 523 Part 2 Testing of rubber and elastomers: testing with the Mooney shearing disk viscometer; equipment requirements DIN 53 523 Part 4 Testing of rubber and elastomers: testing with the Mooney shearing disk viscometer; determining the scorch behaviour
