1、BS EN ISO 4629-2:2016Binders for paints andvarnishes Determination ofhydroxyl valuePart 2: Titrimetric method using a catalyst(ISO 4629-2:2016)BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN ISO 4629-2:2016 BRITISH STANDARDNational forewordThis British Standard
2、 is the UK implementation of EN ISO 4629-2:2016.The UK participation in its preparation was entrusted to Technical Committee STI/3, Paints, media and related products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport t
3、o include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 88348 4 ICS 87.060.20 Compliance with a British Standard cannot confer immunity from legal obligations
4、.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 4629-2 June 2016 ICS 87.060.20 English Version Bi
5、nders for paints and varnishes - Determination of hydroxyl value - Part 2: Titrimetric method using a catalyst (ISO 4629-2:2016) Liants pour peintures et vernis - Dtermination de lindice dhydroxyle - Partie 2: Mthode titrimtrique utilisant un catalyseur (ISO 4629-2:2016) Bindemittel fr Beschichtungs
6、stoffe - Bestimmung der Hydroxylzahl - Teil 2: Verfahren mit Katalysator (ISO 4629-2:2016) This European Standard was approved by CEN on 19 May 2016. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status
7、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-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, Germa
8、n). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia,
9、 Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited
10、 Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN IS
11、O 4629-2:2016 EBS EN ISO 4629-2:2016EN ISO 4629-2:2016 (E) 3 European foreword This document (EN ISO 4629-2:2016) has been prepared by Technical Committee ISO/TC 35 “Paints and varnishes” in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of which is held by
12、DIN. 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 December 2016, and conflicting national standards shall be withdrawn at the latest by December 2016. Attention is drawn to the possibility that
13、 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. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to
14、implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Rom
15、ania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 4629-2:2016 has been approved by CEN as EN ISO 4629-2:2016 without any modification. BS EN ISO 4629-2:2016ISO 4629-2:2016(E)Foreword ivIntroduction v1 Scope . 12 Normative referenc
16、es 13 Terms and definitions . 14 Principle 15 Reagents 26 Apparatus . 27 Sampling 38 Procedure. 38.1 Number of determinations . 38.2 Test portion 38.3 Determination . 38.4 Blank test . 48.5 Determination of acid value 49 Expression of results 410 Precision . 410.1 Repeatability . 410.2 Reproducibili
17、ty . 411 Test report . 5Bibliography 6 ISO 2016 All rights reserved iiiContents PageBS EN ISO 4629-2:2016ISO 4629-2:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International
18、Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, al
19、so take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1.
20、In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elemen
21、ts of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received
22、(see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherenc
23、e to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 35, Paints and varnishes, Subcommittee SC 10, Test methods for binders for paints and varnishes.ISO 4629 consists of the f
24、ollowing parts, under the general title Binders for paints and varnishes Determination of hydroxyl value: Part 1: Titrimetric method without using a catalyst Part 2: Titrimetric method using a catalystiv ISO 2016 All rights reservedBS EN ISO 4629-2:2016ISO 4629-2:2016(E)IntroductionThere are several
25、 different methods standardized for determining the hydroxyl value of resins. The classic method using pyridine without a catalyst is specified in ISO 4629-1. The advantages of the method using a catalyst are the following: the solvents used are less hazardous to health; the solvent consumption is l
26、ower; the method is faster due to shorter reaction times; the end point of the titration is easier to see; polyols are more readily soluble. ISO 2016 All rights reserved vBS EN ISO 4629-2:2016BS EN ISO 4629-2:2016Binders for paints and varnishes Determination of hydroxyl value Part 2: Titrimetric me
27、thod using a catalyst1 ScopeThis part of ISO 4629 specifies a titrimetric method for determining the hydroxyl value of resins, binders for paints and varnishes, primary alcohols, glycols and fats. Whether it can be applied for hydro carboxylic acids, phenolic hydroxyl groups, polyols such as trimeth
28、yl propane and substances containing aromatic groups have been activated for Friedel-Crafts acylation shall be decided on case-to-case basis.Under the right conditions, the method is also applicable for determining the hydroxyl value of castor oil and its derivatives.2 Normative referencesThe follow
29、ing documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 660, Animal an
30、d vegetable fats and oils Determination of acid value and acidityISO 2114:2000, Plastics (polyester resins) and paints and varnishes (binders) Determination of partial acid value and total acid valueISO 3696, Water for analytical laboratory use Specification and test methodsISO 4618, Paints and varn
31、ishes Terms and definitionsISO 15528, Paints, varnishes and raw materials for paints and varnishes Sampling3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.3.1hydroxyl valuenumber of milligrams of potassium hydroxide (KOH)
32、corresponding to hydroxyl groups that have been acetylated under specified test conditions in 1 g of the product testedSOURCE: ISO 4629-1:2016, 3.14 PrincipleThe hydroxyl groups in polyols are acetylated with acetic anhydride. The excess acetic anhydride is titrated with alcoholic potassium hydroxid
33、e solution.INTERNATIONAL STANDARD ISO 4629-2:2016(E) ISO 2016 All rights reserved 1BS EN ISO 4629-2:2016ISO 4629-2:2016(E)5 ReagentsDuring the analysis, use only reagents of recognized analytical grade and only water of at least grade 3 purity as specified in ISO 3696.5.1 N-Methylpyrrolidone (NMP).N
34、OTE Commission chemists workgroup validate methodologies using less dangerous substances such as dioxolane and other hetero cycles.5.2 Potassium hydroxide solution, c = 0,5 mol/l in methanol.Ethanol may also be used if the product to be tested is soluble in ethanol.5.2.1 PreparationWeigh, to the nea
35、rest 0,05 g, 28 g of potassium hydroxide, dissolve in the minimum quantity of water in a 1 000 ml one-mark flask, dilute to the mark with methanol and mix well.5.2.2 StandardizationWeigh, to the nearest 0,01 g, 2,5 g of potassium hydrogen phthalate, previously dried at about 120 C to constant mass a
36、nd allowed to cool in a desiccator, into a 250 ml flask. Add 150 ml freshly boiled and cooled water and swirl until dissolved.Titrate the potassium hydroxide solution prepared in 5.2.1, using phenolphthalein solution as indication, until a red coloration that remains for at least 10 s appears.Calcul
37、ate the actual concentration, c, in moles of hydroxyl ions (OH-) per litre, of the potassium hydroxide solution using Formula (1):cmV=1 000204 22,(1)wherem is the mass, in grams, of potassium hydrogen phthalate taken;V is the volume, in millilitres, of potassium hydroxide solution used for the titra
38、tion;204,22 is the relative molecular mass, in grams per mole, of potassium hydrogen phthalate.5.3 Methyl ethyl ketone (MEK).5.4 Demineralized water.5.5 Acetylating reagent, make up a 10 % solution of acetic anhydride in NMP (5.1).5.6 Catalyst solution, make up a 1 % (by mass) solution of 4-N-dimeth
39、ylaminopyridine in NMP (5.1).5.7 Indicator solution, make up a 1 % (by mass) solution of either thymolphthalein or 0,05 % (by mass) solution of phenolphthalein in NMP (5.1).6 ApparatusOrdinary laboratory equipment and glassware, together with the following.2 ISO 2016 All rights reservedBS EN ISO 462
40、9-2:2016ISO 4629-2:2016(E)6.1 Automatic titrator.6.2 Analytical balance.6.3 250 ml conical flask with grounded joint.6.4 50 ml motorized piston burette.6.5 Hot plate.6.6 Magnetic stirrer.7 SamplingTake a representative sample of the product to be tested, as specified in ISO 15528.8 Procedure8.1 Numb
41、er of determinationsCarry out the determination in triplicate by titrating the sample potentiometrically or using a colour indicator.8.2 Test portionThe initial sample mass required for the determination depends on the expected hydroxyl value and shall be calculated using Formula (2):m =300HVe(2)whe
42、rem is the initial sample mass, in grams;HVeis the expected hydroxyl value, in milligrams of KOH per gram, of the product.Weigh, to the nearest 1 mg, the test portion into the 250 ml conical flask (6.3).8.3 DeterminationAdd 30 ml of catalyst solution (5.6) and 10 ml of acetylating reagent (5.5). Clo
43、se the flask with the stopper and dissolve the sample by stirring and, if necessary, by heating the mixture. Then, while stirring continuously on the magnetic stirrer (6.6), allow the reaction to take place for at least 15 min at ambient temperature (23 2) C.All products containing secondary OHgroup
44、s require a reaction time of at least 60 min, and that is also found to be the case for polyols containing secondary OHgroups.Stop the reaction by adding 3 ml of demineralized water (5.4) and stir for a further 12 min.All products containing secondary OHgroups require a hydrolysis time of at least 3
45、0 min.Remove the flask from the stirrer, rinse the stopper and wall with methyl ethyl ketone (5.3), add two to three drops of indicator solution (5.7) and titrate with potassium hydroxide solution (5.2) until the colourless solution becomes blue (thymolphthalein) or pink (phenolphthalein). ISO 2016
46、All rights reserved 3BS EN ISO 4629-2:2016ISO 4629-2:2016(E)8.4 Blank testCarry out a blank test, following the same procedure, but omitting the test portion.It shall be redetermined on a daily basis.NOTE The value for the blank is around 40 ml.8.5 Determination of acid valueDetermine the acid value
47、 of the sample separately as specified in ISO 2114:2000, Method A. For determination of the acid value of animal and vegetable fats and oils, ISO 660 may be used.9 Expression of resultsCalculate the hydroxyl value, HV, in milligrams of KOH per gram, of the product using Formula (3):HV AV=+(),VVcm015
48、6 1(3)whereV0is the volume, in millilitres, of potassium hydroxide solution (5.2) required for the blank test (8.4);V1is the volume, in millilitres, of potassium hydroxide solution (5.2) required for the determination (8.3);c is the actual concentration, in moles per litre, of the potassium hydroxid
49、e solution (5.2);56,1is the factor for the conversion of millilitres of potassium hydroxide, c(KOH) = 1 mol/l, to milligrams of potassium hydroxide;m is the mass, in grams, of the test portion (8.2);AV is the acid value (8.5), in milligrams of KOH per gram, of the product.Report as the final result the hydroxyl value (individual values and mean) to the nearest 1 mg KOH/g.10 Precision10.1 RepeatabilityTwo determinations made consequently on the same day under repeatability conditions with different masses of the final
