ISO/TC 45/SC 3 - Raw materials (including latex) for use in the rubber industry

This document specifies methods of test for characterizing precipitated hydrated silica for use as a rubber compounding ingredient. This document specifies the test formulation, mixing equipment, mixing procedure and methods of test for use in determining the physical properties of styrene-butadiene rubber compounded with precipitated hydrated silica.

This document provides guidelines and gives requirements on the specification of low protein natural rubber (LPNR). A grading system is proposed, based on the origin of the natural rubber content and differentiated by the two processes, enzymatic and non-enzymatic, applied for removal of the proteins.

This document specifies — physical and chemical tests on raw natural rubbers; — standard materials, standard test formulae, equipment and processing methods for evaluating the vulcanization characteristics of natural rubber (NR).

This document specifies the standard test formulation, mixing procedure and test methods for evaluation of viscoelastic properties in a compound based on solution-polymerized styrene-butadiene rubber (S-SBR), including functionalized S-SBR.

This document defines — the physical and chemical tests on raw reclaimed natural rubber, and — the standard materials, standard test formulations, equipment, and processing methods for evaluating the vulcanization characteristics, and the mechanical properties of reclaimed natural rubber.

This document defines — physical and chemical tests on raw reclaimed isobutene-isoprene (IIR) rubber, and — standard materials, standard test formulations, equipment, and processing methods for evaluating the vulcanization characteristics and the mechanical properties of reclaimed isobutene-isoprene rubber.

This document specifies two methods for the determination of volatile-matter content in raw rubbers by using a hot mill or an oven. These methods are applicable to the determination of the volatile-matter content in the “R” group of rubbers listed in ISO 1629. These are rubbers having an unsaturated carbon chain, for example natural rubber and synthetic rubbers derived at least partly from di-olefins. These methods can also be applicable to other raw rubbers, but in these cases it is necessary to demonstrate that the change in mass is due solely to loss of actual volatile matter and not to rubber degradation. The hot-mill method is not applicable to natural rubber, to synthetic rubbers which are too difficult to handle on a hot mill or to synthetic rubbers in powder or chip form. The two methods do not necessarily give identical results. Therefore, in the case of dispute, the oven method, procedure A, is the reference method. NOTE The applicability of each test method to various types of rubber is summarized in Annex A.

This document specifies: — the physical and chemical tests on raw rubbers, and — the standardized materials, a standardized test formulation, equipment, and processing methods for evaluating the vulcanization characteristics of all types of isobutene-isoprene rubber (IIR).

This document specifies two methods for the determination of the surface tension of polymer dispersions and rubber latices (natural and synthetic). — Method A is the ring method (Du Noüy ring method). — Method B is the plate method (Wilhelmy plate method). Method A is suitable valid for polymer dispersions and rubber latices with a viscosity less than 200 mPa·s. Method B is not suitable for polymer dispersions and rubber latices containing cationic surfactants. Methods A and B are also suitable for prevulcanized latices and compounded material. In case of dispute, the preferred method is method A (the ring method).

This document specifies: — the physical and chemical tests on raw rubbers; — the standard materials, standard test formulations, equipment, and processing methods for evaluating the vulcanization characteristics of ethylene-propylene-diene rubbers (EPDM), including oil-extended types.

This document specifies: — the physical and chemical tests on raw rubbers; — the standard materials, standard test formulations, equipment, and processing methods for evaluating the vulcanization characteristics of styrene-butadiene rubber masterbatches with carbon black or with carbon black and oil.

This document specifies, for acrylonitrile-butadiene rubbers (NBRs): — physical and chemical tests on raw rubbers; — standard materials, a standard test formulation, equipment and processing methods for evaluating the vulcanization characteristics. The mixing preferred method is the single stage mixing with LIM (laboratory internal mixer).

This document specifies guidance on the specification of technically specified rubber (TSR). A grading system is proposed, based on the origin of the natural rubber content and on properties exhibited by the rubber. This document is intended for use by parties involved in the procurement of TSR and is intended to form a basis from which requirements for a particular case may be more closely specified. As such, it describes a number of criteria that need to be the subject of appropriate agreement between the interested parties.

This document specifies two methods for the determination of the specific surface area of types and grades of carbon black for use in the rubber industry: — method A: automatic gas chromatography method (carrier gas method); — method B: automatic volumetric method. Somewhat different results might be obtained from the two methods. The degassing procedure differs between method A and method B, and it is important to investigate the possibility of correcting the results by using standard reference blacks. The results might also differ from those obtained using the multipoint method specified in ISO 18852, which is the preferred method. These methods are not applicable to porous carbon blacks.

This document specifies a method using a differential scanning calorimeter to determine the glass transition temperature of raw rubber and rubber latex.

This document specifies two methods to determine the colour of raw natural rubber according to a standard colour scale: — Method A: colour matching against standard coloured glasses; — Method B: colour determination using colour spectrophotometer. In case of dispute, the preferred method is Method B.

This document specifies a method for determining the bound styrene content of emulsion-polymerized styrene-butadiene rubbers (SBR) by correlation with the measured refractive index of an extracted sample according to a table of refractive indices versus percentage mass fractions styrene. The method is also applicable to extracted oil-extended emulsion-polymerized SBR as long as it produces a film suitable for refractive index measurements. It is not applicable to solution-polymerized SBR.

This document specifies a method for the determination of gel content for technically specified rubbers (TSR).

This document specifies a method for the determination of the volatile fatty acid number of natural rubber latex concentrate. The method is not necessarily suitable for latices from natural sources other than Hevea brasiliensis and is not applicable to compounded latex, vulcanized latex, artificial dispersions of rubber or synthetic rubber latices.

This document specifies a method for the determination of the alkalinity of natural rubber latex concentrate. The method is not necessarily suitable for latices from natural sources other than Hevea brasiliensis or for synthetic rubber latices, compounded latex, vulcanized latex or artificial dispersions of rubber. NOTE A method for the determination of the alkalinity of polychloroprene latex is specified in ISO 13773.

This document specifies a general method for determining the aggregate size distribution (ASD) of silica by using a disc centrifuge according to the principle of sedimentation. As pre-stage the silica is de-agglomerated in water using strong ultrasonic power treatment. The method is used for precipitated silica.

This document specifies a macro-method and a semi-micro method for the determination of nitrogen in raw natural rubber and in natural rubber latex using variants of the Kjeldahl process. NOTE The determination of nitrogen in natural rubber is usually carried out in order to arrive at an estimate of the protein content. Minor amounts of non-proteinous nitrogen containing constituents are also present. However, in the dry solids prepared from natural rubber latex, these materials can make a substantial contribution to the total nitrogen content.

1.1 This document specifies two thermogravimetric methods for the determination of moisture and other volatile-matter content in raw rubbers by using an automatic analyser with an infrared drying unit. 1.2 These methods are applicable to the determination of volatile-matter content in synthetic rubbers (SBR, NBR, BR, IR, CR, IIR, halogenated IIR and EPDM) listed in ISO 1629 and to various forms of raw rubber, such as bale, block, chip, pellet, crumb, powder and sheet. These methods might also be applicable to other raw rubbers only when the change in mass is proven to be due solely to loss of original volatile matter and not to rubber degradation. 1.3 The methods are not applicable to raw rubbers which need homogenizing as specified in ISO 1795. 1.4 The hot-mill method and the oven method specified in ISO 248‑1 and the methods specified in this document might not give identical results. In cases of dispute, therefore, the oven method, procedure A, specified in ISO 248‑1:2011, is the referee method. NOTE These methods can be useful for routine determinations, e.g. quality control, when the measurement conditions for the automatic analyser are fixed for a particular raw rubber or grade of raw rubber.

This document specifies, for general-purpose non-oil-extended, solution-polymerized polyisoprene rubbers (IR): — physical and chemical tests on raw rubbers; — standard materials, a standard test formulation, equipment and processing methods for evaluating the vulcanization characteristics.

This document specifies methods of test for determining the main physical and chemical properties of sulfur used for compounding dry rubber. Several of these properties can be determined by more than one test method and the user can choose the most appropriate method following the description of the test method principles provided under the corresponding clauses. NOTE Typical levels for the relevant properties of sulfur for use as a rubber compounding ingredient are contained in Annex A, for information only.

This document specifies a method for the determination of the bound acrylonitrile content in NBR by an automatic analyser which uses the Kjeldahl method. The method is also applicable to XNBR (carboxylic acrylonitrile-butadiene rubber) and NBIR (acrylonitrile- butadiene-isoprene rubber) as well as NBR latex. NOTE This document and ISO 24698‑1 can give different results on the same rubber sample.

This document specifies a method for the determination of the bound acrylonitrile content in NBR by an automatic analyser which uses a combustion process. The method is also applicable to XNBR (carboxylic acrylonitrile-butadiene rubber) and NBIR (acrylonitrile- butadiene-isoprene rubber) as well as NBR latex. NOTE This document and ISO 24698‑2 can give different results on the same rubber sample.

This document specifies a method for the determination of the KOH number of natural rubber latex concentrate which is preserved wholly or in part with ammonia. The method is applicable to latices containing boric acid. The method is not applicable to latices preserved with potassium hydroxide. It is not necessarily suitable for latices from natural sources other than Hevea brasiliensis, or for latices of synthetic rubber, compounded latex, vulcanized latex or artificial dispersions of rubber.

This document specifies sampling and test methods for the determination of the general characteristics of organic chemicals such as accelerators, antidegradants (including wax) and vulcanizing agents (excluding peroxides).

This document specifies a method for the determination of the light transmittance of the toluene extract from carbon black for use in the rubber industry, as a means of measuring the discolouration caused by the extractable matter. The light transmittance value provides an estimate of the degree of discolouration caused by the toluene-extractable matter present on the surface of the carbon black. This method might not be applicable to carbon blacks with a high extractable-matter content.

ISO 5435:2017 specifies a method for the determination of the tinting strength of carbon black relative to an industry tint reference black. The method is based on the use of five different commercial instruments. Other instruments can be used if the test results for the standard reference blacks are within the control limits given in ASTM D4821. NOTE The Densichron reflectometer and the Meeco Colormaster are no longer commercially available, but the procedures have been included for the benefit of those who still use these instruments.

ISO 2004:2017 gives specifications for natural rubber latex concentrate types which are preserved wholly or in part with ammonia and which have been produced by centrifuging or creaming.

ISO 7781:2017 specifies three methods for the determination of the soap and organic-acid content of raw styrene-butadiene rubber (SBR). - Method A is the titration method using indicator reagent. - Method B is the titration method using an automatic potentiometric titrator. - Method C is the back titration method using an automatic potentiometric titrator. Since the soaps and organic acids present in the rubber are not single chemical compounds, the method gives only an approximate value for the soap and organic-acid content.

ISO 2930:2017 specifies a method for determining the plasticity retention index (PRI) of raw natural rubber. The PRI is a measure of the resistance of raw natural rubber to thermal oxidation. A high resistance to thermal oxidation is shown as a high value of the index. PRI is not an absolute value and cannot give an absolute classification of plasticity number of different natural rubber after oxidation.

ISO 11236:2017 applies to a variety of substituted p-phenylenediamine antidegradants (PPDs) used in the rubber industry. The three general classes of PPDs are dialkyl, alkyl-aryl and diaryl, which are used to impart ozone resistance to rubber. The following test methods are of greatest significance in assessing the purity of production PPDs, and hence their suitability for use in rubber. They are specified in this document as follows: - determination of purity by gas chromatography (GC); - determination of purity by high-performance liquid chromatography (HPLC); - determination of ash; - determination of volatile matter.

ISO 20851:2017 specifies the method to examine the presence and approximate count of viable aerobic and facultative anaerobic microorganisms in synthetic rubber latices. Identification of the microorganisms is outside the scope of this document.

ISO 20299-2:2017 specifies the material and physical property requirements for non-strippable low density polyethylene film for wrapping natural rubber bales comprising of block natural rubber of 33,33 kg or 35 kg and natural rubber ribbed smoked sheets including bales of 33,33 kg, 35 kg, 50 kg and 111,11 kg, or any other bale weights as mutually agreed between the parties, and intended to keep the bales separate during transportation and storage.

ISO 1795:2017 specifies a method for the sampling of raw rubber in bales, blocks or packages and further procedures carried out on the samples to prepare test samples for chemical and physical tests.

ISO 19846:2017 specifies: - a coding system of reclaimed natural rubber and reclaimed isobutylene-isoprene (IIR) rubber; - a numeric system to classify reclaimed rubber.

ISO 11852:2017 specifies a titration method for the determination of the magnesium content of field natural rubber latex.

ISO 9298:2017 specifies the methods to be used for the evaluation of zinc oxide for use in the rubber industry. The analytical methods are applicable to all commercial zinc oxides, for example: - direct type (American process); - indirect type (French process); - other types produced by different chemical methods, i.e. precipitation and calcination. Zinc oxide can also be coated with organic materials, such as fatty acids, oil, wetting agents, etc., in order to improve the dispersion in rubber.

ISO 15825:2017 specifies a method for determining the size distribution of carbon black aggregates, using a disc centrifuge photosedimentometer. This technique is based on the hydrodynamic behaviour of carbon black in a centrifugal field. The determination of the aggregate size distribution is important in the evaluation of carbon black used in the rubber industry.

ISO 1437:2017 specifies a method for determining the water-wash sieve residue from regular, untreated carbon black for the rubber industry. It may not be applicable to oil-treated blacks because the oil could prevent proper wetting of the black by water.

ISO 1434:2016 specifies two methods for the determination of the amount of bale coating present on the outside wrapper sheets of bales of natural rubber: - ashing method; - brushing or scraping method. The ashing method is the preferred method.

ISO 11344:2016 describes a method for the determination of the molecular mass, expressed as polystyrene, and the molecular-mass distribution of polymers produced in solution which are completely soluble in tetrahydrofuran (THF) and which have a molecular-mass range from 5 × 103 to 1 × 106. It is not the purpose of this International Standard to explain the theory of gel permeation chromatography.

ISO 1304:2016 specifies methods for the determination of iodine adsorption number of carbon blacks for use in the rubber industry. Two titration methods are described: - method A: titration using a burette and starch as indicator; - method B: potentiometric titration with an automatic titrator. The iodine adsorption number is related to the surface area of a carbon black and is generally in agreement with the nitrogen surface area. However, it is significantly depressed in the presence of a high content of volatile or solvent-extractable materials; the iodine adsorption number therefore does not always provide a measure of the specific surface area of a carbon black. Ageing of carbon black can also influence the iodine number. In case of dispute, the preferred method is method B (potentiometric titration).

ISO 6235:2016 specifies a method for the determination of the long polystyrene block content of raw uncompounded styrene-butadiene rubber (SBR) and raw uncompounded blends of block SBR. It is not applicable to blends of block SBR with EPDM, IIR, CSM and other halogenated rubbers. The method is applicable to raw, uncompounded latices of the above compositions and is suitable for rubbers having block polystyrene contents in the range from 5 % (by weight) to 100 % (by weight). Rubbers having block polystyrene contents of less than 5 % (by weight) may yield incorrect results unless a correction factor, based on information gained by working with such rubbers, is applied. The method is intended for use on gel-free rubbers, but it may be used on rubbers containing gel if it has been proved that the gel does not interfere.

ISO 19246:2016 specifies a general method for determining the liquid absorption capacity of a pigment and extender by using di-(2-ethylhexyl) adipate (DOA, CAS 103-23-1). The determination of the DOA absorption number is performed by means of an absorptometer which is equipped with a torque measurement and processing system. The DOA absorption number provides an indication of the void volume formed by the aggregates and agglomerates of the pigments and extenders.

ISO 249:2016 specifies a method for the determination of the dirt content of raw natural rubber. It is not applicable to dirt present as surface contamination.

ISO 14558:2016 specifies a method for determining the residual unsaturation in hydrogenated nitrile rubber (HNBR) by measuring the infrared (IR) absorbance of HNBR films cast from solution. ISO 14558:2016 assumes that samples and IR spectra are prepared and analysed by experienced personnel and that equipment is operated in accordance with the manufacturer's instructions. Details for operating an IR spectrometer are not included in this method.