BS ISO 6502-3:2018 pdf download – Rubber — Measurement of vulcanization characteristics using curemeters Part 3: Rotorless curemeter
1 Scope
This document specifies a method for determining selected vulcanization characteristics of a rubber compound by means of a rotorless curemeter. The introduction to the use of curemeters is given in ISO 6502‑1.
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 6502‑1:2018, Rubber — Measurement of vulcanization characteristics using curemeters — Part 1: Introduction ISO 18899:2013, Rubber — Guide to the calibration of test equipment 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 6502‑1 apply.
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4 Principle
A test piece of rubber is placed in a heated cavity formed by two dies, one of which is oscillated at a given frequency and amplitude. This action exerts a shear strain on the test piece and a shear torque which depends on the stiffness (shear modulus) of the rubber. The torque that increases as vulcanization proceeds is measured by a torque sensor incorporated in the other die member. The torque is recorded autographically as a function of time. The stiffness of the rubber test piece increases as vulcanization proceeds.
The curve is complete when the recorded torque rises either to an equilibrium value or to a maximum value (see ISO 6502‑1). If the torque continues to increase, vulcanization is considered to be complete after a given time. The time required to obtain a vulcanization curve is a function of the test temperature and the characteristics of the rubber compound.
The vulcanization characteristics are obtained from the recorded curve of torque as a function of time, in accordance with ISO 6502‑1.
5 Apparatus
5.1 General A rotorless curemeter consists of two dies that are heated and closed or almost closed, under a specified force, to form a test cavity that contains a test piece. One of the dies oscillates, and reaction torque on the stationary die, which is opposite to the moving die, can be measured at specified conditions of temperature, frequency and amplitude. There are two types of assembly surrounding the test cavity formed by the upper and lower dies, one is unsealed or open type, and the other is sealed type. In the case of a sealed type die system, the die cavity is surrounded by seal plates and seal rings, and is completely closed. In the unsealed type the cavity is not completely closed. Two kinds of cavity shape formed by the dies are used, namely, a biconical shape and a flat plate shape. Three types of curemeter with different combination of sealing type and die cavity shape are available:
a) biconical die cavity with unsealed system,
b) biconical die cavity with sealed system, or
c) flat plate die cavity (with sealed system).
The general arrangements for rotorless curemeters are shown in Figure 1, Figure 2 and Figure 3, including typical machine dimensions. Curemeters with different design might result in different torque responses and cure time (see ISO 6502‑1:2018, A.2). BS ISO 6502-3 pdf download.