1、BS EN ISO14896:2009ICS 83.080.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPlastics Polyurethaneraw materials Determination ofisocyanate content(ISO 14896:2009)This British Standard was published under the authority of the Standards Policy and Strategy Comm
2、ittee on 30 September 2009 BSI 2009ISBN 978 0 580 65655 2Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 14896:2009National forewordThis British Standard is the UK implementation of EN ISO 14896:2009. It supersedes BS EN ISO 14896:2001 which is withdrawn.The UK participation in
3、its preparation was entrusted to Technical Committee PRI/42, Fibre reinforced thermosetting plastics and prepregs.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract.
4、 Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 14896February 2009ICS 83.080.10 Supersedes EN ISO 14896:2001 English VersionPlastics - Polyurethane raw materials
5、- Determination ofisocyanate content (ISO 14896:2009)Plastiques - Matires premires des polyurthannes -Dtermination de la teneur en isocyanate (ISO 14896:2009)Kunststoffe - Polyurethanrohstoffe - Bestimmung desIsocyanatanteils (ISO 14896:2008)This European Standard was approved by CEN on 19 January 2
6、009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on
7、 application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Cent
8、re has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
9、Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means
10、reservedworldwide for CEN national Members.Ref. No. EN ISO 14896:2009: EBS EN ISO 14896:2009EN ISO 14896:2009 (E) 3 Foreword This document (EN ISO 14896:2009) has been prepared by Technical Committee ISO/TC 61 “Plastics“ in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat
11、 of which is held by NBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 2009, and conflicting national standards shall be withdrawn at the latest by August 2009. Attention is drawn to the
12、 possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 14896:2001. According to the CEN/CENELEC Internal Regulations, the national sta
13、ndards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
14、Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 14896:2009 has been approved by CEN as a EN ISO 14896:2009 without any modification. BS EN ISO 14896:2009ISO 14896:2009(E) ISO 2009 All rights reserved iiiContents Page Forewo
15、rd iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 2 4 Principle. 2 4.1 Method A 2 4.2 Method B 2 5 Application 2 6 Interferences . 2 7 Sampling 3 8 Test conditions . 3 9 Reagents 3 10 Apparatus 4 11 Method A Toluene/dibutylamine with aqueous HCI . 4 11.1 Procedure 4 11.2 Expressi
16、on of results . 5 11.3 Precision and bias 6 11.4 Test report . 6 12 Method B Toluene/TCB/DBA with methanolic HCI . 7 12.1 Procedure 7 12.2 Expression of results . 8 12.3 Precision and bias. 8 12.4 Test report . 9 BS EN ISO 14896:2009ISO 14896:2009(E) iv ISO 2009 All rights reservedForeword ISO (the
17、International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee
18、 has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnic
19、al standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bo
20、dies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying an
21、y or all such patent rights. ISO 14896 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting materials. This third edition cancels and replaces the second edition (ISO 14896:2006), of which it constitutes a minor revision, the main purpose of which was to combine
22、 the standard with its amendment (ISO 14896:2006/Amd.1:2007), thereby adding a new subclause (12.1.8). BS EN ISO 14896:2009INTERNATIONAL STANDARD ISO 14896:2009(E) ISO 2009 All rights reserved 1Plastics Polyurethane raw materials Determination of isocyanate content SAFETY STATEMENT Persons using thi
23、s document should be familiar with normal laboratory practice, if applicable. This document does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with
24、 any regulatory requirements. 1 Scope This lnternational Standard specifies two methods for the measurement of the isocyanate content of aromatic isocyanates used as polyurethane raw materials. Method A is primarily applicable to refined toluene diisocyanate (TDI), methylene-bis-(4-phenylisocyanate)
25、 (MDI) and their prepolymers. Method B is applicable to refined, crude or modified isocyanates derived from toluene diisocyanate, methylene-bis-(4-phenylisocyanate) and polymethylene polyphenylisocyanate. It can also be used for isomer mixtures of toluene diisocyanate, methylene-bis-(4-phenylisocyan
26、ate) and polymethylene polyphenylisocyanate. Other aromatic isocyanates may be analysed by this method if precautions are taken to verify suitability. It is not applicable to blocked isocyanates. 2 Normative references The following referenced documents are indispensable for the application of this
27、document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 385, Laboratory glassware Burettes ISO 648, Laboratory glassware Single-volume pipettes ISO 3696, Water for analytical laborat
28、ory use Specification and test methods ISO 4787, Laboratory glassware Volumetric glassware Methods for use and testing of capacity ISO 4788, Laboratory glassware Graduated measuring cylinders ISO 6353-1, Reagents for chemical analysis Part 1: General test methods ISO 6353-2, Reagents for chemical an
29、alysis Part 2: Specifications First series ISO 6353-3, Reagents for chemical analysis Part 3: Specifications Second series ISO 14898:1999, Plastics Aromatic isocyanates for use in the production of polyurethane Determination of acidity BS EN ISO 14896:2009ISO 14896:2009(E) 2 ISO 2009 All rights rese
30、rved3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 polyurethane polymer prepared by the reaction of an organic di- or polyisocyanate with compounds containing two or more hydroxyl groups NOTE Polyurethanes may be thermosetting, thermoplastic
31、, rigid or soft and flexible, cellular or non-cellular. 3.2 assay percent by mass of a specific isocyanate present in a sample 3.3 isocyanate content NCO content percent by mass of the NCO groups present in a sample 3.4 amine equivalent mass of sample that will combine with 1 gram-equivalent of dibu
32、tylamine 4 Principle 4.1 Method A The isocyanate sample is reacted with an excess of dibutylamine in toluene to form the corresponding substituted urea. After cooling to room temperature, acetone is added as a co-solvent, then the reaction mixture is back-titrated with standardized aqueous HCI using
33、 potentiometric or colorimetric end point determination. 4.2 Method B The isocyanate sample is reacted with an excess of dibutylamine in a toluene/trichlorobenzene solvent to form the corresponding substituted urea. After cooling to room temperature, the reaction mixture is diluted with methanol and
34、 back-titrated potentiometrically or colorimetrically with methanolic hydrochloric acid. See also 12.1.8. 5 Application These test methods can be used for research or for quality control purposes to characterize isocyanates used in polyurethane products. 6 Interferences Phosgene, the carbamyl chlori
35、de of the isocyanate, hydrogen chloride and any other acidic or basic compounds will interfere. In refined isocyanates, these impurities are usually present in such small amounts that they do not affect the determination; however, some crude or modified isocyanates may contain acidities of up to app
36、roximately 0,3 %, so the value reported for the NCO content of unrefined isocyanates should preferably be designated as “corrected” or “uncorrected” for acidity. BS EN ISO 14896:2009ISO 14896:2009(E) ISO 2009 All rights reserved 37 Sampling Since organic isocyanates react with atmospheric moisture,
37、take special precautions in sampling (see warning). Usual sampling methods (for example, sampling an open drum with a thief), even when conducted rapidly, can cause contamination of the sample with insoluble ureas; therefore, blanket the sample with a dry inert gas (e.g. nitrogen, argon or dried air
38、) at all times. WARNING Organic isocyanates are hazardous when absorbed through the skin, or when the vapours are breathed. Provide adequate ventilation and wear protective gloves and eyeglasses. 8 Test conditions Since isocyanates react with moisture, keep the laboratory humidity low, preferably be
39、low 50 % relative humidity. 9 Reagents Use reagent-grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of ISO 6353-1, ISO 63535-2 and ISO 6353-3. Other grades may be used, provided that it is first determined that the reagent
40、 is of sufficiently high purity to permit its use without lessening the accuracy of the determination. Unless otherwise indicated, references to water shall be understood to mean grade 3 water as defined in ISO 3696. 9.1 Acetone (method A). 9.2 Toluene, dried over type 4A molecular sieve. 9.3 di-n-b
41、utylamine solution, 1 mol/l (method A). Dilute 129 g of di-n-butylamine to 1 litre with toluene. 9.4 di-n-butylamine solution, 2 mol/l (method B). Dilute 258 g of di-n-butylamine to 1 litre with toluene. 9.5 Aqueous hydrochloric acid, 1 mol/l (method A). Prepare 1 mol/l aqueous hydrochloric acid and
42、 standardize frequently enough to detect changes of 0,001 mol/l. 9.6 Methanolic hydrochloric acid, 1 mol/l (method B). Prepare 1 mol/l hydrochloric acid in methanol and standardize frequently enough to detect changes of 0,001 mol/l. NOTE In order to have homogeneous solutions, it is recommended that
43、 methanolic HCI be used in this procedure. If desired, aqueous HCI can be used; however, turbidity will be encountered in some titrations. It is recommended that 200 ml to 250 ml of methanol be added to the reacted product to minimize the formation of two layers. Experience has shown that, if the mi
44、xtures are agitated vigorously, inhomogeneity can be tolerated without adversely affecting the results. 9.7 Bromophenol blue indicator solution, for colorimetric titration: 0,04 % aqueous solution of bromophenol blue sodium salt, reagent grade, or 0,04 % solution of bromophenol blue in acetone. 9.8
45、1,2,4-Trichlorobenzene (TCB), dried over type 4A molecular sieve (method B). 9.9 Methanol (method B). BS EN ISO 14896:2009ISO 14896:2009(E) 4 ISO 2009 All rights reserved10 Apparatus 10.1 Potentiometric titrator or pH-meter, accurate to 0,1 mV or better, equipped with a pair of electrodes or a combi
46、nation glass-calomel electrode (filled with a 1 mol/l lithium chloride solution in methanol, or an equivalent solution) and a piston burette having a 20 ml capacity. 10.2 Syringes, capacity 2 ml and 5 ml, and syringes with a large orifice suitable for weighing viscous prepolymers by difference to th
47、e nearest 1 mg. 10.3 Magnetic stirrer. 10.4 Analytical balance, accurate to 0,1 mg. 10.5 Iodine flask, capacity 500 ml, with ground-glass neck (method A). 10.6 Conical flask, capacity 250 ml, with a wide mouth (method B). 10.7 Volumetric pipettes, capacity 25 ml (method A) and 20 ml (method B), conf
48、orming to ISO 4787. 10.8 Measuring pipette, capacity 1 ml, conforming to ISO 648. 10.9 Graduated cylinders, capacity 250 ml (method A) and 100 ml (method B), conforming to ISO 4788. 10.10 Beaker, capacity 500 ml. 10.11 Burette, capacity 50 ml, for colorimetric titration, conforming to ISO 385. 11 Me
49、thod A Toluene/dibutylamine with aqueous HCI 11.1 Procedure 11.1.1 Using a volumetric pipette (10.7), add 25 ml of 1 mol/l dibutylamine solution (9.3) to an iodine flask (10.5). Rinse the walls of the flask with 10 ml of toluene (9.2). 11.1.2 Weigh a sample of the product to be analysed to the nearest 0,1 mg using a suitable syringe (10.2). The sample used for analysis shall be completely liquid; if it contains crystallized isocyanates, heat it carefully until a homogeneous liquid phase is obtained. Add m0grams o
