ISO/TC 45/SC 2/WG 1 - Physical properties

This document specifies a method for the determination of the tendency of vulcanized or thermoplastic rubbers to adhere to and to corrode metals when exposed to a specified test environment.

This document specifies a static procedure, known as the Gehman test, for determining the relative stiffness characteristics of vulcanized or thermoplastic rubbers over a temperature range from room temperature to approximately −120 °C.

This document specifies a method of test for measuring the force required to separate, by stripping, two plies of fabric bonded with rubber, or a rubber layer and a fabric ply bonded together. The method is applicable when the ply surfaces are approximately plane or when they are in the form of a cylinder having an internal diameter greater than approximately 50 mm. The method is not applicable when the ply surfaces contain sharp bends, angles or other gross irregularities which cannot be excluded when cutting out test pieces. This document does not apply to coated fabrics, which are tested in accordance with ISO 2411, or textile conveyor belts, which are tested in accordance with ISO 252.

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.

This document specifies three methods for estimating the staining of organic finishes (subsequently referred to as "organic material") by vulcanized or thermoplastic rubber, as defined in Clause 3: — method A: contact staining and migration staining; — method B: extraction staining; — method C: penetration staining;

This document specifies a method for the determination of the temperature-retraction characteristics of stretched vulcanized rubber. This document does not cover thermoplastic rubbers, as many thermoplastic elastomers have a yield point in the range of 5 % to 20 % elongation.

This document specifies requirements for tensile-testing systems operating at constant rate of traverse and suitable for testing rubbers, plastics and adhesives, although any one system might only be applicable to a narrower range of materials. It also covers such systems when used for flexural, shear and compression tests.

This document specifies a method for the determination of the adhesive strength of a vulcanized or thermoplastic rubber bonded to a rigid substrate, using a test piece comprising a strip of rubber bonded to a single plate of rigid material. The test is carried out at a peel angle of 90°. The method is applicable primarily to test pieces prepared in the laboratory under standard conditions, such as can be used to provide data for the choice of rubber compounds or adhesive systems, the development of such materials and the control of manufacturing processes. This method is not suitable for high-hardness rubbers, typically above 85 IRHD.

This document specifies a method for the determination of the volume and the surface resistivity of vulcanized or thermoplastic rubbers. The method can be applied to materials with a resistivity from 101 Ω⋅m to 1017 Ω⋅m.

This document specifies a method for the determination of the insulation resistance of vulcanized and thermoplastic rubbers without discrimination between the volume and surface resistances involved. This method is applicable only to the test pieces with a resistance greater than 108 Ω. NOTE Methods of test for test pieces with a lower resistance are described in ISO 1853 and ISO 2878. Because the test pieces are simply and easily prepared, this method is particularly useful for rapidly determining values which will give a general indication of quality when great accuracy is not required.

This document specifies a method for the determination of the gas transmission rate and gas permeability coefficient of vulcanized or thermoplastic rubber under conditions in which the overall pressure on each side of the rubber test piece is the same, using gas chromatography to determine the quantity of gas that permeates through the rubber. The method applies to vulcanized and thermoplastic rubbers of hardness not less than 35 IRHD (international rubber hardness degrees) and to both single gases and mixtures of gases.

This document specifies a method for determining the indentation hardness (Shore hardness) of vulcanized or thermoplastic rubber using durometers with the following scales: — the A scale for rubbers in the normal-hardness range; — the D scale for rubbers in the high-hardness range; — the AO scale for rubbers in the low-hardness range and for cellular rubbers; — the AM scale for thin rubber test pieces in the normal-hardness range.

This document specifies a method for determining the indentation hardness of vulcanized or thermoplastic rubber by means of a pocket hardness meter calibrated in IRHD. The use of such meters is primarily intended for control, not specification, purposes (for specification, see ISO 48-2). It is possible to increase precision by fixing the pocket hardness meter on a support.

This document specifies procedures for the calibration and verification of durometers of types A, D, AO and AM (see ISO 48-4), IRHD pocket meters (see ISO 48-5), IRHD dead-load instruments (see ISO 48-2) and dead-load instruments using the very low rubber hardness scale (see ISO 48-3).

This document specifies four methods for the determination of the hardness of vulcanized or thermoplastic rubbers on flat surfaces (standard-hardness methods) and four methods for the determination of the apparent hardness of curved surfaces (apparent-hardness methods). The hardness is expressed in international rubber hardness degrees (IRHD). The methods cover the hardness range from 10 IRHD to 100 IRHD. These methods differ primarily in the diameter of the indenting ball and the magnitude of the indenting force, these being chosen to suit the particular application. The range of applicability of each method is indicated in Figure 1. This document does not specify a method for the determination of hardness by a pocket hardness meter, which is described in ISO 48-5. This document specifies the following four methods for the determination of standard hardness. — Method N (normal test) is appropriate for rubbers with a hardness in the range 35 IRHD to 85 IRHD, but can also be used for hardnesses in the range 30 IRHD to 95 IRHD. — Method H (high-hardness test) is appropriate for rubbers with a hardness in the range 85 IRHD to 100 IRHD. — Method L (low-hardness test) is appropriate for rubbers with a hardness in the range 10 IRHD to 35 IRHD. — Method M (microtest) is essentially a scaled-down version of the normal test method N, permitting the testing of thinner and smaller test pieces. It is appropriate for rubbers with a hardness in the range 35 IRHD to 85 IRHD, but can also be used for hardnesses in the range 30 IRHD to 95 IRHD. NOTE 1 The value of the hardness obtained by method N within the ranges 85 IRHD to 95 IRHD and 30 IRHD to 35 IRHD might not agree precisely with that obtained using method H or method L, respectively. The difference is not normally significant for technical purposes. NOTE 2 Because of various surface effects in the rubber and the possibility of slight surface roughness (produced, for example, by buffing), the microtest might not always give results agreeing with those obtained by the normal test. This document also specifies four methods, CN, CH, CL and CM, for the determination of the apparent hardness of curved surfaces. These methods are modifications of methods N, H, L and M, respectively, and are used when the rubber surface tested is curved, in which case there are two possibilities: a) the test piece or product tested is large enough for the hardness instrument to rest upon it; b) the test piece or product tested is small enough for both the test piece and the instrument to rest upon a common support. A variant of b) would be where the test piece rests upon the support surface of the instrument. Apparent hardness can also be measured on non-standard flat test pieces using methods N, H, L and M. The procedures described cannot provide for all possible shapes and dimensions of test piece, but cover some of the commonest types, such as O-rings.

This document specifies a method for the determination of the apparent hardness of vulcanized- or thermoplastic-rubber roller covers, expressed as the Pusey and Jones indentation value. The Pusey and Jones plastometer apparatus is used to measure the depth of indentation of an indentor under a specified force into the surface of the rubber. The indentation value is not the same as that measured by the international rubber hardness test method ISO 48-2, since in this method the rubber immediately adjacent to the indentor is precompressed. The Pusey and Jones indentation value is an inverse measurement of hardness, i.e. the harder the rubber the lower the Pusey and Jones indentation value.

This document specifies a method for the determination of the apparent hardness, expressed in International Rubber Hardness Degrees (IRHD), of vulcanized- or thermoplastic-rubber roller covers. The method is similar in principle to the methods used for the determination of the hardness of rubber in ISO 48-2 in that it consists essentially of measuring the depth of penetration of a spherical indentor operating under a specified force. The apparatus used is similar to that described in ISO 48-2, having a base specifically designed for application to roller covers and similar curved surfaces. NOTE With some rollers, there can be significant variation in the thickness of the rubber over the surface of the roller, which could affect the measured apparent hardness.

This document provides guidance on the determination of the hardness of vulcanized and thermoplastic rubbers. It is intended to provide an understanding of the significance of hardness as a material property and to assist in the selection of an appropriate test method.

This document specifies a dead-load method for the determination of the hardness of very soft vulcanized or thermoplastic rubbers using the very low rubber hardness (VLRH) scale. The relation between the depth of penetration and the VLRH scale is linear.

This document specifies a method for the determination of the apparent hardness of vulcanized- or thermoplastic-rubber roller covers, expressed in Shore hardness, for measurement where only medium precision is required. The method and apparatus used are essentially those described in ISO 48-4, the measurements in this case being made on the curved surface of the conditioned rubber-covered roller rather than on a flat test piece. Shore type A and type D instruments are specified, the latter being used for measurements on rollers of high hardness. NOTE With some rollers, there can be significant variation in the thickness of the rubber over the surface of the roller, which could affect the measured apparent hardness.

This document specifies the requirements for the laboratory testing of the volume resistivity of specially prepared test pieces of vulcanized or thermoplastic rubber compounds rendered conducting or dissipative by the inclusion of carbon black or ionizable materials. The tests are suitable for materials with a resistivity of less than about 108 Ω⋅m. Method 1 is the preferred method when test pieces with bonded electrodes are not available. Method 2 is the preferred method when test pieces are moulded with the inclusion of bonded electrodes. Method 3 is another method that can be used if the apparatus for method 1 or 2 is not available, but it has lower accuracy. If a reference to this document is made without specifying the method, method 1 is used.

This document specifies two methods of test for the determination of the density of solid vulcanized and thermoplastic rubbers. Such determinations are of importance in the control of the quality of a rubber compound and in the calculation of the mass of rubber required to produce a given volume of material. This document does not cover the determination of the relative density of rubber, which is the ratio of the mass of a given volume of rubber to the mass of an equal volume of pure water at a given temperature.

ISO 37:2017 specifies a method for the determination of the tensile stress-strain properties of vulcanized and thermoplastic rubbers. The properties which can be determined are tensile strength, elongation at break, stress at a given elongation, elongation at a given stress, stress at yield and elongation at yield. The measurement of stress and strain at yield applies only to some thermoplastic rubbers and certain other compounds.

ISO 7743:2017 specifies methods for the determination of the compression stress-strain properties of vulcanized or thermoplastic rubber using a standard test piece, a product or a part of a product. Four procedures are given: - using standard test piece A with the metal plates lubricated (method A); - using standard test piece A with the metal plates bonded to the test piece (method B); - using standard test piece B (method C); - using a product or a part of a product with the metal plates lubricated (method D). The methods are not suitable for materials that exhibit high set.

ISO 6179:2017 specifies two methods for determining, by measurement of the transmission rate, the permeability of rubber to volatile liquids diffusing into open air. It is applicable only to materials in sheet form and to coated fabrics having thicknesses between 0,2 mm and 3,0 mm. It is restricted to transmission rates of more than 0,1 g/m2·h. The methods are particularly useful for comparing the relative transmission rates of one liquid through different materials, or of several liquids through one material. Method A, with refilling, is used when testing mixtures of liquids which give different transmission rates. Method B, with no refilling, is used for a single-component liquid. NOTE A method for the determination of water vapour transmission rate is given in ISO 2528.

ISO 5603:2017 specifies two methods for determining the adhesion strength of vulcanized rubber to wire cord which is embedded in the rubber. The two methods do not necessarily give the same results. They are applicable primarily to test pieces prepared in the laboratory under standard conditions and used for the development and control of materials and processes utilized in the manufacture of products reinforced with wire cord. NOTE The methods can also be used for single wire, for example bead wire. Method 1 reduces the dependence of the measured adhesion on the modulus and strength properties of the rubber.

ISO 812:2017 specifies a method for determining the lowest temperature at which rubber materials do not exhibit brittle failure or the temperature at which half of the test pieces used in a test fail when impacted under specified conditions. The temperatures thus determined do not necessarily relate to the lowest temperature at which the material can be used since the brittleness will be affected by the conditions of test and especially by the rate of impact. Data obtained by this method are, therefore, intended to be used to predict the behaviour of rubbers at low temperatures only in applications in which the conditions of deformation are similar to those specified in the test. Three procedures are described: - procedure A, in which the brittleness temperature is determined; - procedure B, in which the brittleness temperature for 50 % failure is determined; - procedure C, in which the test piece is impacted at a specified temperature. Procedure C is used in the classification of rubber materials and for specification purposes. NOTE A similar test for rubber-coated fabrics is described in ISO 4646.

ISO 814:2017 specifies a method for determining the adhesion strength of rubber-to-metal bonds where the rubber part is assembled between two parallel metal plates, using the adhesive system under investigation. The method is applicable primarily to test pieces, prepared in the laboratory under standard conditions, such as can be used to provide data for the development of rubber compounds and control of methods of manufacture.

ISO 2878:2017 specifies a method of test to determine the electrical resistance of antistatic and conductive products manufactured wholly or in part from rubber whose electrical resistance measured between defined points, when new, does not exceed 3 × 108 Ω and whose conductivity is derived from the addition of carbon black and/or other appropriate substances to the bulk of the material. NOTE Highly conductive mixes cannot be made in this way. ISO 2878:2017 specifies the electrode configuration for basic geometries, but it is intended that reference be made to relevant product specifications for requirements for specific products. It does not apply to: a) products the relevant surfaces of which are composed of mixtures of insulating and conductive areas; b) products with a substantial surface area of insulating material, except for footwear (which does not normally have a conductive or antistatic upper).

ISO 5600:2017 specifies a method for the determination of the static vulcanized adhesion strength of rubber compounds to rigid materials. The test piece is composed of two conical ends of the rigid material, joined by a cylinder of rubber. The adhesion is obtained by a bonding system which can include not only the rigid material and the rubber compound, but other elements such as thin alloy coatings or chemical treatments of rigid parts and either a single cement or both primer and cover cements. The bonding system for preparing the test pieces should be adequately specified by the user, but provision is made in this document for the evaluation of different types of failure related to a complex bonding system. The method is designed primarily for test pieces prepared in the laboratory under standard conditions in order to provide data for development and control of bonding systems and their components, such as cements or special rubber compounds, and of methods of manufacture. While intended to be applied where the rubber is bonded to rigid supporting pieces, it might not cover such cases where the support, although of high-modulus material, has a low rigidity due to small transverse dimensions, as in the case of rubber bonded to metal wires, cords or thin sheets.

ISO 23529:2016 specifies general procedures for the preparation, measurement, marking, storage, and conditioning of rubber test pieces for use in physical tests specified in other International Standards, and the preferred conditions to be used during the tests. Special conditions, applicable to a particular test or material or simulating a particular climatic environment, are not included, nor are special requirements for testing whole products. ISO 23529:2016 also specifies the requirements for the time interval to be observed between forming and testing of rubber test pieces and products. Such requirements are necessary to obtain reproducible test results and to minimize disagreements between customer and supplier.

ISO 1827:2016 specifies methods for the determination of the modulus in shear and the strength of bonds of rubber to metal or other rigid plates, using rubber bonded between four parallel plates. Method A describes the determination of the modulus in shear. Method B describes the determination of the strength of the bonds. The methods are applicable primarily to test pieces prepared in the laboratory under standard conditions, such as can be used to provide data for the development and control of rubber compounds and methods of manufacture of bonded shear units.

ISO 2782-1:2016 specifies three methods for the determination of the permeability to gases of vulcanized or thermoplastic rubber under a differential partial pressure. The three methods specified are as follows: - pressure sensor method (using vacuum): for determining the gas transmission rate, gas permeability coefficient, gas diffusion coefficient and gas solubility coefficient; - simplified sensor method (using applied pressure): for determining the gas permeability coefficient only; - gas-chromatographic method: for determining the gas transmission rate and gas permeability coefficient. These methods apply to vulcanized and thermoplastic rubbers of hardness not less than 35 IRHD (international rubber hardness degrees) and to both single gases and mixtures of gases.

ISO 6133:2015 specifies five methods of calculating, after testing, the tear strength and the adhesion strength of vulcanized rubber or fabrics coated with or adhered to rubber or plastics. The results are calculated by determining the median and range of peak values from a graphical plot of force versus time recorded during the test. A trace for an adhesion strength test or tear strength test can show few or many force peaks, depending on the material under investigation. The choice of the method of calculation depends on the number of peaks in the trace. The purpose of this International Standard is to obtain more uniformity in the evaluation and presentation of test results. It is applicable only, however, when specified in another International Standard, i.e. a method of test or a specification. For other details, such as apparatus, test piece preparation, conditioning, procedure, etc., requirements given in the relevant International Standard shall apply. NOTE In certain cases, the methods of analysis given might not be adequate, for example, for peak values showing a trend with time. In cases where the minimum force values are of interest, it is possible to use the same methods of calculation as when determining from a range of peak values.

ISO 34-2:2015 specifies a method for the determination of the tear strength of small test pieces (Delft test pieces) of vulcanized or thermoplastic rubber. NOTE The method does not necessarily give results agreeing with those given by the method described in ISO 34‑1, which uses trouser, angle and crescent test pieces. It is used in preference to ISO 34‑1 when the amount of material available is limited, and might be particularly suitable for testing small finished products.

ISO 34-1:2015 specifies three test methods for the determination of the tear strength of vulcanized or thermoplastic rubber, namely the following: - method A, using a trouser test piece; - method B, using an angle test piece, with or without a nick of specified depth; - method C, using a crescent test piece with a nick. The value of tear strength obtained depends on the shape of the test piece, speed of stretching, and temperature of test. It can also be susceptible to grain effects in rubber.

ISO 18899:2013 outlines the principles of calibration of rubber test equipment and gives guidance on the general requirements for ensuring measurement traceability, establishing the basis for deciding calibration intervals, and estimating measurement uncertainty.

ISO 1432:2013 specifies a static procedure, known as the Gehman test, for determining the relative stiffness characteristics of vulcanized or thermoplastic rubbers over a temperature range from room temperature to approximately −150 °C.

ISO 4647:2010 specifies a method for the determination of the static adhesion of textile cord to vulcanized rubber using the H‑pull test. It is applicable to cords made from natural or man-made fibres. The property levels obtained with this method are affected considerably by the history of the cord and the rubber compound. The method yields data, however, on which a judgement as to the service quality of the material can be based. The method is primarily intended for use with tyre cord. However, it can be applied, if desired, to similar cords for use in other rubber products, but it is limited to cords of linear density not exceeding 800 mg/m (tex).

ISO 24454:2008 identifies specific test procedures for the acquisition and presentation of comparable multi-point data for selected properties of rubber compounds. The data for each property are generated, using a single test method, as a function of important variables such as time, temperature and environmental effects. An important application consists in helping different suppliers produce material specification sheets in which the same set of properties is measured using the same conditions. Guidance on the interpretation of results is provided.

ISO 24453:2008 identifies specific test procedures for the acquisition and presentation of comparable single-point data for properties of rubber compounds. In general, each property is specified by a single test method and a single experimental value although, in certain cases, properties may be represented by more than one value obtained under different test conditions. The properties presented are those used to characterize processing properties, those most often quoted by manufacturers and in material specifications, and those relevant to more specific applications. An important application consists in helping different suppliers produce material specification sheets in which the same set of properties is measured using the same conditions.

ISO 4664:2004 provides guidance on the determination of dynamic properties of vulcanized and thermoplastic rubbers. It includes both free- and forced-vibration methods carried out on both materials and products. It does not cover rebound resilience or cyclic tests in which the main objective is to fatigue the rubber.

ISO 11345:2006 specifies qualitative visual methods for the rapid and comparative assessment of the degree of macrodispersion of carbon black and carbon black/silica in rubber. Ratings are made relative to a set of standard reference photographs, and the results are expressed on a numerical scale from 1 to 10. In addition, a method is given for rating the presence of large agglomerates on a numerical scale (ratings 1 to 10).

ISO 15113:2005 outlines the principles governing the measurement of coefficient of friction and describes a method suitable for measuring the coefficient of friction of a rubber against standard comparators, against itself, or against any other specified surface.

ISO 7267-1:2017 specifies a method for the determination of the apparent hardness, expressed in International Rubber Hardness Degrees (IRHD), of vulcanized- or thermoplastic-rubber roller covers. The method is similar in principle to the methods used for the determination of the hardness of rubber in ISO 48 in that it consists essentially of measuring the depth of penetration of a spherical indentor operating under a specified force. The apparatus used is similar to that described in ISO 48, having a base specifically designed for application to roller covers and similar curved surfaces. NOTE With some rollers, there can be significant variation in the thickness of the rubber over the surface of the roller, which could affect the measured apparent hardness.

ISO 7267-3:2017 specifies a method for the determination of the apparent hardness of vulcanized- or thermoplastic-rubber roller covers, expressed as the Pusey and Jones indentation value. The Pusey and Jones plastometer apparatus is used to measure the depth of indentation of an indentor under a specified force into the surface of the rubber. The indentation value should not be confused with hardness as measured by the international rubber hardness test method ISO 48,[1] since in this method the rubber immediately adjacent to the indentor is precompressed. The Pusey and Jones indentation value is an inverse measurement of hardness, i.e. the harder the rubber the lower the Pusey and Jones indentation value.

ISO 36:2017 specifies a method of test for measuring the force required to separate, by stripping, two plies of fabric bonded with rubber, or a rubber layer and a fabric ply bonded together. The method is applicable when the ply surfaces are approximately plane or when they are in the form of a cylinder having an internal diameter greater than approximately 50 mm. The method is not applicable when the ply surfaces contain sharp bends, angles or other gross irregularities which cannot be excluded when cutting out test pieces. ISO 36:2017 does not apply to coated fabrics, which are tested in accordance with ISO 2411, or textile conveyor belts, which are tested in accordance with ISO 252.

ISO 813:2016 specifies a method for the determination of the adhesive strength of a vulcanized or thermoplastic rubber bonded to a rigid substrate, using a test piece comprising a strip of rubber bonded to a single plate of rigid material. The test is carried out at a peel angle of 90°. The method is applicable primarily to test pieces prepared in the laboratory under standard conditions, such as can be used to provide data for the choice of rubber compounds or adhesive systems, the development of such materials and the control of manufacturing processes. This method is not suitable for high-hardness rubbers, typically above 85 IRHD.