1、July 2009DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 83.080.20!$XC%“1533202www
2、.din.deDDIN EN ISO 14896Plastics Polyurethane raw materials Determination of isocyanate content (ISO 14896:2009)English version of DIN EN ISO 14896:2009-07Kunststoffe Polyurethanrohstoffe Bestimmung des Isocyanatanteils (ISO 14896:2009)Englische Fassung DIN EN ISO 14896:2009-07SupersedesDIN EN ISO 1
3、4896:2002-04www.beuth.deDocument comprises 16 pagesDIN EN 14896:2009-07 2 National foreword This standard has been prepared by Technical Committee ISO/TC 61 “Plastics” in collaboration with Technical Committee CEN/TC 249 “Plastics”, (Secretariat: NBN, Belgium) The responsible German body involved in
4、 its preparation was the Normenausschuss Kunststoffe (Plastics Standards Committee), Technical Committee NA 054-02-01 AA Hrtbare Harze. During work on the revision of this standard the German experts made recommendations regarding the following subclauses which, however, could not be incorporated at
5、 this time: The following paragraph should be added to clause 1: Considering the precision of these methods, the isocyanate content determined using them cannot be used to characterize purity (or main component content) of refined TDI and methylene-bis-(4-phenylisocyanate) (MDI) because industrial p
6、roducts normally only contain traces of secondary components, the isocyanate content of which is similar to that of the main component. In subclause 12.1.8, third paragraph, the use of a mixture of 2-propanol and ethylene glycol (1:1, v/v) should also be allowed. The following should be added to the
7、 fifth paragraph of subclause 12.1.8: In the case of toluene diisocyanate, methylene-bis-(4-phenylisocyanate), and polymethylene polyphenyliso-cyanate, if the sample is sufficiently soluable it may be dissolved directly in the dibutylamine solution without the addition of any other solvent. The DIN
8、Standards corresponding to the International Standards referred to in this document are as follows: ISO 385 DIN EN ISO 385 ISO 648 DIN EN ISO 648 ISO 3696 DIN ISO 3696 Amendments This standard differs from DIN EN ISO 14896:2002-04 as follows: a) The standard has been editorially revised. b) Normativ
9、e references have been updated. c) Subclause 12.1.8 has been added. Previous editions DIN EN ISO 9369: 1997-08 DIN EN ISO 14896: 2002-04 DIN EN 14896:2009-07 3 National Annex NA (informative) Bibliography DIN EN ISO 385, Laboratory glassware Burettes DIN EN ISO 648, Laboratory glassware Single-volum
10、e pipettes DIN ISO 3696, Water for analytical laboratory use Specification and test methods DIN EN 14896:2009-07 4 This page is intentionally blank. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 14896 February 2009 ICS 83.080.10 Supersedes EN ISO 14896:2001 English Version Plastics olyure
11、thane raw materials Determination of isocyanate content (ISO 14896:2009) Plastiques atires premires des polyurthannes termination de la teneur en isocyanate (ISO 14896:2009)Kunststoffe Polyurethanrohstoffe This European Standard was approved by CEN on 19 January 2009. CEN members are bound to comply
12、 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 national standards may be obtained on application to the CEN Management
13、 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 Centre has the same status as the off
14、icial 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, Portugal, Romania,Slovakia, Sl
15、ovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN
16、 national Members. Ref. No. EN ISO 14896:2009: EBestimmung des Isocyanatanteils (ISO 14896:2009) Contents Page 1 Scope . 4 2 Normative references . 4 3 Terms and definitions. 5 4 Principle. 5 4.1 Method A 5 4.2 Method B 5 5 Application 5 6 Interferences . 5 7 Sampling 6 8 Test conditions . 6 9 Reage
17、nts 6 10 Apparatus 7 11 Method A Toluene/dibutylamine with aqueous HCI . 7 11.1 Procedure 7 11.2 Expression of results . 8 11.3 Precision and bias 9 11.4 Test report . 9 12 Method B Toluene/TCB/DBA with methanolic HCI .10 12.1 Procedure 10 12.2 Expression of results .10 12.3 Precision and bias.11 12
18、.4 Test report .12 DIN EN ISO 14896:2009-07EN ISO 14896:2009 (E)2Foreword. 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 of which is held by NBN. This European
19、 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 possibility that some of the elements
20、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 standards organizations of the following c
21、ountries 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, Portugal, Romania, Slovakia, Slovenia,
22、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. DIN EN ISO 14896:2009-07EN ISO 14896:2009 (E)3SAFETY STATEMENT Persons using this document should be familiar with normal laborat
23、ory 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 any regulatory requirements. 1 Scope This lntern
24、ational 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) (MDI) and their prepolymers. Method B is applica
25、ble 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-phenylisocyanate) and polymethylene polyphenylisocyanate. Othe
26、r 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 document. For dated references, only the edition
27、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 laboratory use Specification and test methods ISO 4787,
28、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 analysis Part 2: Specifications First series ISO 63
29、53-3, 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 DIN EN ISO 14896:2009-07EN ISO 14896:2009 (E)43 Terms and definitions For the purposes of this document, the foll
30、owing 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, rigid or soft and flexible, cellular or non-cellular. 3.2 assay perce
31、nt 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 dibutylamine 4 Principle 4.1 Method A The isocyanate sample is reacted with
32、 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 potentiometric or colorimetric end point determination. 4.2 Method B T
33、he 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 back-titrated potentiometrically or colorimetrically with methanolic h
34、ydrochloric 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 chloride of the isocyanate, hydrogen chloride and any other acidic or basic c
35、ompounds 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 approximately 0,3 %, so the value reported for the NCO content of unrefine
36、d isocyanates should preferably be designated as “corrected” or “uncorrected” for acidity. DIN EN ISO 14896:2009-07EN ISO 14896:2009 (E)57 Sampling Since organic isocyanates react with atmospheric moisture, take special precautions in sampling (see warning). Usual sampling methods (for example, samp
37、ling 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) at all times. WARNING Organic isocyanates are hazardous when absorbed through the skin, or
38、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 below 50 % relative humidity. 9 Reagents Use reagent-grade chemicals in all tests. Unless other
39、wise 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 is of sufficiently high purity to permit its use without lessening the accuracy of the deter
40、mination. 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-butylamine solution, 1 mol/l (method A). Dilute 129 g of di-n-butylamine to 1 litre with tolue
41、ne. 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 standardize frequently enough to detect changes of 0,001 mol/l. 9.6 Methanolic hydrochloric
42、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 methanolic HCI be used in this procedure. If desired, aqueous HCI can be used; however, turb
43、idity 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 mixtures are agitated vigorously, inhomogeneity can be tolerated without adversely affecting th
44、e 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 1,2,4-Trichlorobenzene (TCB), dried over type 4A molecular sieve (method B). 9.9 Methanol (me
45、thod B). DIN EN ISO 14896:2009-07EN ISO 14896:2009 (E)610 Apparatus 10.1 Potentiometric titrator or pH-meter, accurate to 0,1 mV or better, equipped with a pair of electrodes or a combination glass-calomel electrode (filled with a 1 mol/l lithium chloride solution in methanol, or an equivalent solut
46、ion) 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 the nearest 1 mg. 10.3 Magnetic stirrer. 10.4 Analytical balance, accurate to 0,1 mg. 10.5 Iodine flask, capacity 500
47、 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), conforming to ISO 4787. 10.8 Measuring pipette, capacity 1 ml, conforming to ISO 648. 10.9 Graduated cylinders, capacit
48、y 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 Method A Toluene/dibutylamine with aqueous HCI 11.1 Procedure 11.1.1 Using a volumetric pipette (10.7), add 25 ml of
49、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 of the product to the dibutylamine solution in the iodine flask. The mass (m0) in grams of the product to be analyse
