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

This document specifies two test methods for the determination of water content of raw rubber and compounded rubber using a coulometric Karl Fischer titration method: — method A uses an evaporator of heating tube type oven; — method B uses an evaporator of vial type oven. It applies to the water content range between 0,01 % and 1 %. In case of dispute, method B is the preferred method.

This document specifies: — the physical and chemical tests on raw rubbers; — the standard materials, the standard test formulations, the equipment and the processing methods to evaluate the vulcanization characteristics for general-purpose chloroprene rubbers (CRs).

This document specifies the material and physical property requirements for non-strippable, low-density polyethylene (LDPE) film for the wrapping of: — natural rubber bales comprised of block natural rubber of 33,3 kg or 35 kg; — natural rubber ribbed smoked sheets, including bales of 33,3 kg, 35 kg, 50 kg and 111,11 kg; — modified natural rubber (e.g. epoxidized natural rubber, low-protein natural rubber) bales of 33,3 kg or 35 kg; — any other bale masses as mutually agreed between the parties, and intended to keep the bales separate during transportation and storage.

This document specifies procedures for the quantitative determination of the microstructure of the butadiene portion and the content of styrene in solution-polymerized SBR (S-SBR) by Fourier transform infrared spectrometry (FTIR) with attenuated total reflection (ATR) method. The styrene content is expressed in mass fraction relative to the S-SBR. The contents of three microstructure types, i.e. vinyl, trans and cis, are expressed in mol fraction relative to the butadiene portion in the S-SBR. This method is only applicable to raw rubbers. NOTE 1 Precision as shown in Annex A is not always possible to obtain for S-SBRs containing polystyrene block or styrene content more than 45 %. NOTE 2 Only “vinyl”, “trans” and “cis”, are used in this document. However, the expression of vinyl, trans and cis mean as follows in general: — vinyl: vinyl unit, vinyl bond, 1,2-unit, 1,2-bond, 1,2-vinyl-unit or 1,2-vinyl-bond; — trans: 1,4-trans unit, 1,4-trans bond, trans-1,4 unit or trans1,4 bond; — cis: 1,4-cis unit, 1,4-cis bond, cis-1,4 unit or cis-1,4 bond.

This document specifies a method to determine 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.

This document specifies a method to identify the presence of phytosterol including β-sitosterol in natural rubber in raw and vulcanised forms.

This document 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.

This document specifies a method for the determination of the dry rubber content of natural rubber field latex. The method is not suitable for latices from natural sources other than Hevea brasiliensis, or for compounded latex, vulcanized latex or artificial dispersions of rubber.

This document specifies four methods for the determination of the content of the following groups of organic peroxides used as rubber vulcanizing agents. There are three titration methods and one gas-chromatography method. a) titration method A for group a: Peroxyketals: 1,1-Di(tert-butylperoxy)cyclohexane (DTBPC; CAS Registry Number®:3006-86-8) 1,1-Di(tert-butylperoxy)-2-methylcyclohexane (DBPMC; CAS RN 147217‑40‑1); 1,1-Di(tert-butylperoxy)-3,3,5-trimethylcylcohexane (DBPTC; CAS RN 6731‑36‑8); 2,2-Di(tert-butylperoxy)butane (DBPB; CAS RN 2167‑23‑9); Butyl −4,4-di(tert-butylperoxy)valerate (BPV; CAS RN 995‑33‑5); b) titration method B for group b: Diacyl peroxides: Dibenzoyl peroxide (CAS RN 94‑36‑0); Di(2,4-dichlorobenzoyl) peroxide (CAS RN 133‑14‑2); Di(4-methylbenzoyl) peroxide (CAS RN 895‑85‑2); c) titration method C for group c: Diaralkyl and alkyl-aralkyl peroxides: Di(tert-butylperoxyisopropyl)benzene (CAS RN 2212‑81‑9); Dicumyl peroxide (CAS RN 80‑43‑3); tert-Butyl cumyl peroxide (CAS RN 3457‑61‑2); d) gas-chromatography for dialkyl peroxides, using a capillary or packed column. 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane (CAS RN 78‑63‑7)

This document specifies the methods to be used for the evaluation of sulfenamide accelerators: — MBTS: benzothiazyl disulphide; — CBS: N-cyclohexylbenzothiazole-2-sulfenamide; — TBBS: N-tert-butylbenzothiazole-2-sulfenamide; — DIBS: N,N'-diisopropylbenzothiazole-2-sulfenamide; — DCBS: N,N'-dicyclohexylbenzothiazole-2-sulfenamide; — MBS: N-oxydiethylenebenzothiazole-2-sulfenamide. NOTE 1 Although MBTS is not a sulfenamide, it is the primary decomposition product of these accelerators and quantitatively determined by the method specified in 5.2. The analytical methods are applicable for most commercial sulfenamide accelerators: — sulfenamides of primary amines (type I); — sulfenamides of unhindered secondary amines (type II); — sulfenamides of hindered secondary amines (type III). NOTE 2 Classification and key properties of sulfenamide accelerators are described in Annex A. The method (5.2) to determine purity by high performance liquid chromatography (HPLC) is the preferred method.

This document specifies a method for the determination of the bound acrylonitrile content of emulsion-polymerized NBR lattices. The method is applicable to NBR lattices having a bound acrylonitrile content between 18 % and 45 %. It is also applicable to, for example, carboxylic-nitrile-butadiene (XNBR) lattices and nitrile-isoprene (NIR) lattices.

This document specifies a quantitative method, using proton (1H) nuclear magnetic resonance (NMR) spectrometry, for the determination of epoxidation and ring opening level of raw epoxidized natural rubber (ENR). This method applies to ENR of all grades available commercially.

This document specifies the physical and chemical requirements of epoxidized natural rubber (ENR) based on the epoxidation level of the natural rubber.

This document specifies a method for the determination of total phosphate content of natural rubber latex concentrate. This method is not necessarily suitable for latex from natural sources other than the Hevea brasiliensis.

This document specifies a method for the determination of the bound styrene content of styrene-butadiene rubber (SBR) lattices. The method is applicable to hot (approximately 50 °C) emulsion polymerized SBR lattices having a bound styrene content, expressed on the SBR content, of up to 55 % and to cold (approximately 5 °C) emulsion polymerized SBR lattices having a bound styrene content between 18 % and 40 %. The method is not applicable to reinforced styrene-butadiene rubber (SBR. .Y) lattices, carboxylic-styrene-butadiene rubber (XSBR) lattices and pyridine-styrene-butadiene rubber (PSBR) lattices.

This document specifies: — physical and chemical tests on raw rubbers; — standard materials, standard test formulations, equipment, and processing methods for evaluating the vulcanization characteristics of emulsion- and solution-polymerized styrene-butadiene rubbers (SBRs), including oil-extended rubbers. It applies to those rubbers listed in Table 1 which are normally used in vulcanized form.

This document specifies a method for the determination of the high-speed mechanical stability of synthetic rubber latex. The method is not applicable to compounded synthetic rubber latices.

This document provides specifications for natural rubber latex concentrate which has low protein content [low protein natural rubber (LPNR) latex], as follows: — LPNR latex: field latex or concentrated latex pretreated with deproteinising agent, centrifuged and preserved after concentration with ammonia only, with an alkalinity of at least a mass fraction of 0,6 % calculated with respect to the latex. This document is applicable to medical rubber products and avoids the possibility of allergies. This document covers requirements for LPNR latex, type HA (high ammonia), and LPNR latex, type LA (low ammonia).

This document specifies the test methods to be used for magnesium oxide intended for use in the rubber industry as a stabilizer and vulcanizing agent. The choice of the properties to be determined and the values required are subject to agreement between the interested parties.

This document specifies two methods for the determination of the total sulfur in all types of carbon black for use in the rubber industry: — Method A, using a combustion furnace; — Method B, using an automatic analyser. With respect to safety aspects and test precision, it is preferable to use automatic systems. Method B is therefore the preferred method. Classical chemical analysis (Method A) is acceptable if automatic equipment is not available.

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 — 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 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 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 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 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 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 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.