ISO/TC 61/SC 2/WG 5 - Temperature dependent behavior

1.1 This document gives a general test method for the determination of the temperature of deflection under load (flexural stress under three-point loading) of plastics. Different types of test specimen and different constant loads are defined to suit different types of material. 1.2 ISO 75-2 gives specific requirements for plastics (including filled plastics and fibre-reinforced plastics in which the fibre length, prior to processing, is up to 7,5 mm) and ebonite, while ISO 75-3 gives specific requirements for high-strength thermosetting laminates and long-fibre-reinforced plastics in which the fibre length, prior to processing, is greater than 7,5 mm. 1.3 The methods specified are suitable for assessing the relative behaviour of different types of material at elevated temperature under load at a specified rate of temperature increase. The results obtained do not necessarily represent maximum applicable temperatures because, in practice, essential factors, such as time, loading conditions and nominal surface stress, can differ from the test conditions. True comparability of data can only be achieved for materials having the same room-temperature flexural modulus. 1.4 The methods specify preferred dimensions for the test specimens. 1.5 Data obtained using the test methods described are not intended to be used to predict actual end-use performance. The data are not intended for design analysis or prediction of the endurance of materials at elevated temperatures. 1.6 This method is commonly known as the heat deflection temperature or heat distortion temperature (HDT) test, although there is no official document using this designation.

ISO 306:2013 specifies four methods for the determination of the Vicat softening temperature (VST) of thermoplastic materials: method A50 using a force of 10 N and a heating rate of 50 K/h; method B50 using a force of 50 N and a heating rate of 50 K/h; method A120 using a force of 10 N and a heating rate of 120 K/h; method B120 using a force of 50 N and a heating rate of 120 K/h. The methods specified are applicable only to thermoplastics, for which they give a measure of the temperature at which the thermoplastics start to soften rapidly.

ISO 75-2:2013 specifies three methods, using different values of constant flexural stress, which can be used for the determination of the temperature of deflection under load of plastics (including filled plastics and fibre-reinforced plastics in which the fibre length, prior to processing, is up to 7,5 mm) and ebonite: method A, using a flexural stress of 1,80 MPa; method B, using a flexural stress of 0,45 MPa; method C, using a flexural stress of 8,00 MPa.

ISO 75-3:2004 specifies a method for the determination of the temperature of deflection under load of high-strength thermosetting laminates and compression-moulded long-fibre-reinforced plastics in which the fibre length is greater than 7,5 mm. The flexural stress used is not fixed, as in ISO 75-2, but is a fraction (1/1000) of the initial (room-temperature) flexural modulus of the material under test. This allows the method to be applied to materials with a wide range of flexural moduli.

Application of the general method in ISO 458-1 for the above mentioned plastics according to the special case of the method with an angle of deflection between 55 and 65 . The temperatures according to three characteristic values of the torsion stiffness; 300 MPa, 23 MPa and 4 MPa are to be determined for the material under test.

Specification of a general method for the determination of the stiffness in torsion at various temperatures, particularly below 0 °C. An observation of torque and angle of deflection is made after an arbitrarily fixed time of load application, using the specified testing apparatus. This procedure is employed at a single temperature or at selected temperature intervals over a range specified for the material to be tested. The stiffness in torsion is expressed as the apparent torsional modulus of elasticity for each temperatur.

ISO 75-1:2013 gives a general test method for the determination of the temperature of deflection under load (flexural stress under three-point loading) of plastics. Different types of test specimen and different constant loads are defined to suit different types of material.

ISO 306:2004 specifies four methods for the determination of the Vicat softening temperature (VST) of thermoplastic materials: Method A50 using a force of 10 N and a heating rate of 50 °C/h Method B50 using a force of 50 N and a heating rate of 50 °C/h Method A120 using a force of 10 N and a heating rate of 120 °C/h Method B120 using a force of 50 N and a heating rate of 120 °C/h. The methods specified are applicable only to thermoplastics, for which they give a measure of the temperature at which the thermoplastics start to soften rapidly.

ISO 75-2:2004 specifies three methods, using different values of constant flexural stress, that can be used for the determination of the temperature of deflection under load of plastics (including filled plastics and fibre-reinforced plastics in which the fibre length, prior to processing, is up to 7,5 mm) and ebonite: method A, using a flexural stress of 1,80 MPa; method B, using a flexural stress of 0,45 MPa; method C, using a flexural stress of 8,00 MPa.

ISO 75-1:2004 specifies a general test method for the determination of the temperature of deflection under load (flexural stress under three-point loading) of plastics. Different types of test specimen and different constant loads are defined to suit different types of material.

Specifies four methods for the determination: method A50 using a force of 10 N and a heating rate of 50 °C/h, method B50 using a force of 50 N and a heating rate of 50 °C/h, method A120 using a force of 10 N and a heating rate of 120 °C/h, method B120 using a force of 50 N and a heating rate of 120 °C/h. The principle is determining the temperature at which a standard indenter penetrates 1 mm into the surface. The methods are applicable only to thermoplastics, for which they give a measure of the temperature at which the thermoplastics start to soften rapidly.

The principle of the method specified is subjecting a standard test specimen to a bending stress under three-point loading to produce one of the nominal surface stresses in the relevant part of this standard, raising the temperature at a uniform rate, measuring the temperature, at which a specified deflection occurs. The results obtained do not necessarily represent maximum use temperatures.

The principle of the method specified is subjecting a standard test specimen to a bending stress to produce one of the nominal surface stresses (method A: 1,80 MPa, method B: 0,45 MPa, method C: 8,00 MPa), raising the temperature at a uniform rate, measuring the temperature, at which a specified deflection occurs. The test specimens are tested in one of two positions, flatwise or edgewise, the requirements on test-specimen dimensions being different in each case. The methods give better reproducibility with amorphous plastics than with semi-crystalline ones.

The principle of the method specified is subjecting a standard test specimen to a bending stress equal to 1/10 of a specified or measured flexural strength, raising the temperature at a uniform rate, measuring the temperature, at which a specified deflection occurs. The test load used is not a fixed load as in part 2, but a function of the ultimate or specified load. This allows the method to be applied to materials with a wide range of strength and bending moduli.