BS ISO 289-2:2020 pdf download.Rubber, unvulcanized — Determinations using a shearing-disc viscometer.
WARNING 1 — Persons using this document should be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to determine the applicability of any other restrictions.
WARNING 2 — Certain procedures specified in this document might involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handlingand disposal after use.
1 Scope
This document specifies a method for determining the pre-vulcanization characteristics of compounded rubber.
The pre-vulcanization characteristics determined by this method provide a means of estimating how long compounded rubber can he maintained at high temperatures and remain processable.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 289-1, Rubber, unvulcanized — Determinations using a shearing-disc viscometer — Part 1:
Determination of Mooney viscosity
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropediaorg/
3.1
pre-vulcanizatlon tIme scorch time
time including warm-up time, for the viscosity to increase by a specified amount from the minimum value
Note 1 to entry: It is expressed in minutes.
4 Principle
The test consists of determining how the Mooney viscosity of the rubber compound changes with running time at a specified temperature relevant to the process for which the compound is to he used. The time at which the Mooney viscosity has increased by a specified number of units is recorded.
5 Apparatus
The apparatus specified in Iso 289-1 shall be used. It is permissible to use the small rotor for high- viscosity compounds.
6 Calibration schedule
See Annex A.
7 Preparation of test specimen
Prepare the two discs comprising the test specimen from a sheet of rubber compound, using the procedure for preparation of test pieces described in ISO 289-1.
8 Test temperature
Choose a test temperature relevant to the process for which the compound is to be used.
9 Procedure
Use the procedure described in ISO 289-1. The pre-heating time shall be 1 mm, and the test shall be continued until the viscosity reaches the specified number of units above the minimum. When a large rotor is used, the increase is specified as five units and when a small rotor is used, the increase is specified as three units. The corresponding pre-vulcanization times are designated t5 and t3, respectively. A typical trace obtained with the large rotor is shown in Figure 1.BS ISO 289-2 pdf download.