BS ISO 3387:2020 pdf free.Rubber- Determination of crystallization effects by hardness measurements.
BS ISO 3387 1 Scope This document specifies a test based on hardness measurements for determining the progressive stiffening of rubber with time, caused by crystallization. It is limited to materials having an initial hardness at a test temperature of from 10 IRHD to 85 IRHD. The method is applicable to raw, unvulcanized [compounded) and vulcanized rubber. It is mainly of interest for rubber with a marked crystallization tendency at temperatures experienced in cold climates, such as chloroprene and natural rubber. The method is not applicable to fast-crystallizing materials which crystallize to a considerable degree within the timespan of 15 min used for conditioning at test temperature. 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 48-2:2018, Rubber, vulcanized or thermoplastic一Determination of hardness一Part 2: Hardness between 10 IRHD and 100 IRHD ISO 18899:2013, Rubber一Guide to the calibration of test equipment ISO 23529， Rubber 一General procedures for preparing and conditioning test pieces for physical test methods.3 Terms and definitions No terms and definitions are listed in this document.ISO and IEC maintain terminological databases for use in standardization at the following addresses: 一ISO Online browsing platform: available at https://www.iso.org/obp 一IEC Electropedia: available at http://www.electropedia.org/ 4 Principle One or the other of the following measurements is made on a test piece stored at the desired temperature: a) the increase in hardness after a specified storage time; b) the time required for a specified increase in hardness to occur.Test pieces of raw and of unvulcanized (compounded) rubber shall be prepared by placing a suitable quantity in a preheated mould and then applying heat and pressure (5.5) for a suitable time. The mould, still under pressure, shall be cooled to standard laboratory temperature (see ISO 23529). After 15 min, the pressure shall be released, and the test piece removed. It shall be free from blisters and porosity. Values of mould temperature and time of application of pressure required to produce a suitable test piece depend upon the type of rubber. A temperature of 150 °C applied for 3 min has been found suitable for many raw rubbers, while a temperature of 120 °C applied for 3 min has been found satisfactory for many compounded rubbers. However, for some materials, longer times or higher mould temperatures might be necessary to ensure a smooth and flat test piece surface. Under no circumstances shall conditions be used that cause incipient cure or degradation. BS ISO 3387 pdf download.