SIST EN ISO 2495:2001

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Modri trdni pigmenti - Specifikacije in metode preskušanja (ISO 2495:1995)Eisenblau-Pigmente - Anforderungen und Prüfverfahren (ISO 2495:1995)Pigments de bleu de Prusse - Spécifications et méthodes d'essai (ISO 2495:1995)Iron blue pigments - Specifications and methods of test (ISO 2495:1995)87.060.10Pigmenti in polnilaPigments and extendersICS:Ta slovenski standard je istoveten z:EN ISO 2495:2000SIST EN ISO 2495:2001en01-januar-2001SIST EN ISO 2495:2001SLOVENSKI
STANDARD
INTERNATIONAL STANDARD ISO 2495 Second edition 1995-03-15 Iron blue Pigments - Specifications and methods of test Pigments de bleu de Prusse - Spkifications et methodes d’essai Reference number ISO 2495:1995(E) SIST EN ISO 2495:2001

ISO 2495:1995(Ej Foreword ISO (the 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. Esch 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, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 2495 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 2, Pigments and extenders. This second edition cancels and replaces the first edition (ISO 2495:1972), which has been technically revised. Annex A of this International Standard is for information only. 0 ISO 1995 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case Postale 56 l CH-l 211 Geneve 20 l Switzerland Printed in Switzerland ii SIST EN ISO 2495:2001

INTERNATIONAL STANDARD 0 ISO ISO 2495: 1995(E) Iron blue Pigments - Specifications and methods of test 1 Scope This International Standard specifies the requirements and the corresponding methods of test for iron blue Pigments. 2 Normative references The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the Standards indicated below. Members of IEC and ISO maintain registers of cur- rently valid International Standards. ISO 385-1 :1984, Laboratory glassware - Burettes - Part 1: General requiremen ts. ISO 648: 1977, Laboratory glassware - One-mark pipettes. ISO 787-1 :1982, General methods of test for pig- ments and extenders - Part 1: Comparison of colour of Pigments. ISO 787-2:1981, General methods of test for pig- ments and extenders - Part 2: Determination of matter volatile at 105 “C. ISO 787-3:1979, General methods of fest for pig- ments and extenders - Part 3: Determination of matter soluble in water - Hot extraction method. ISO 787-4:1981, General methods of test for pig- ments and extenders - Part 4: Determination of acidity or alkalinity of the aqueous extract. ISO 787-5:1980, General methods of test for pig- ments and extenders - Part 5: Determination o f oil absorp tion value. ISO 787-16:1986, General methods of test for pig- ments and extenders - Part 16: Determination of relative tin ting s trength (or equivalen t colouring value) and colour on reduction of coloured Pigments - Vis- ual comparison me thod. ISO 842: -l), ßaw materials for paints and varnishes - Sampling. ISO 1042:1983, Laboratory glassware - One-mark volume tric flasks. ISO 3696: 1987, Wa ter for analytical laboratory use - Specification and test methods. ISO 8780-2:1990, Pigments and extenders - Meth- ods of dispersion for assessment of dispersion char- ac teris tics - Part 2: Dispersion using an oscillator-y shaking machine. 3 Definition For the purposes of this International Standard, the following definition applies. 3.1 iron blue Pigment: A Pigment formed by the reaction of iron salts with cyanoferrate(lI) or cyanoferrate(III) ions and followed, if necessary, by treatment with oxidizing agents. 1) To be published. (Revision of ISO 842:1984) SIST EN ISO 2495:2001

ISO 2495: 1995(E) 4 Required characteristics and associated tolerantes 6 Identification 6.1 Reagents 4.1 Composition The Pigment shall be essentially an iron blue Pigment as defined in clause 3. The Pigment, after drying as described in 9.1 and examination as described in clauses 7 and 8, shall comply with the following re- quirements: a) The sum of the iron(ll) and iron(lll) ions (basic iron content), together with the iron cyanoferrate complex content [expressed as Fe(CN),] shall be not less than 70 % (v&Iz). b) The total iron content (expressed as Fe) shall be not less than 30 % (m/m). The Pigment, when examined by the procedure de- scribed in clause 6, shall be free from added colouring matter. NOTE 1 The Pigment may contain substances added during manufacture for the purpose of improving the quality or working properties, or both, of the Pigment. 4.2 Appearance The material shall be in the form of a soft dry powder or in such a condition that it may be readily reduced thereto by crushing under a Palette knife, without grinding action. 4.3 Other characteristics 4.3.1 For iron blue Pigments complying with this International Standard, the essential requirements are specified in table 1 and the conditional requirements are Iisted in table2. The conditional requirements shall be specified by agreement between the interested Parties. 43.2 The agreed reference Pigment referred to in table 2 shall comply with the requirements of table 1. 5 Sampling Take a representative Sample of the product to be tested, as described in ISO 842. During the analysis, use only reagents of recognized analytical grade and only water of at least grade 3 purity as defined in ISO 3696. WARNING - Use the reagents in accordance with the appropriate health and safety regulations. 6.1.1 Sodium hydroxide, 50 g/l solution. 6.1.2 Hydrochlorit acid, diluted 1 d- 1. Add 1 part by volume of concentrated hydrochloric acid [approximately 37 % (WZ/.), p N 1 p 19 g/ml] to 1 part by volume of water. 6.2 Apparatus Use ordinary laboratory apparatus and glassware. 6.3 Procedure Place approximately 0,l g of the Pigment in a 50 ml beaker and add 15 ml of the sodium hydroxide sol- ution (6.1 .l). Heat the beaker until the liquid boils and continue to heat for 5 min. Check that the blue color- ation has been completely destroyed by examining the liquid in the beaker against an illuminated white background. Ignore a reddish-brown precipitate which may be formed as this only indicates the presence of iron( I II) hydroxide. NOTE 2 If the blue coloration is not completely de- stroyed, this indicates the presence of an added Pigment that is not iron blue as defined in clause 3. Cool the liquid in the beaker and slowly add the hydrochloric acid (6.1.2) until the liquid is faintly acid to Iitmus. Examine the liquid for reformation of the characteristic iron blue coloration. 6.4 Assessment of results Record whether the Pigment Sample is completely decolorized by treatment with alkali and is reformed on acidification. SIST EN ISO 2495:2001

0 ISO ISO 2495: 1995(E) Table 1 - Essential requirements \ Characteristic lJnit Requirement Method of test Volatile matter w(VM) % (mhn) 2,0 < w(VM) < 6,0 See clause 9 Matter soluble in water % (mhn) max. 2 ISO 787-3 (hot extraction method) Acidity or alkalinity of the ml of 0,l mol/1 Solution per max. 20 ISO 787-4 aqueous extract 100 g of Pigment 7.1 Method A Table 2 - Conditional requirements Characteristic Requirement Method of test Colour Equal to that of ISO 787-1 the agreed refer- ’ Colour on re- ence Pigment duction (see 4.3.2) to within a toler- ante agreed be- ISO 787-16 Relative tinting tween the strength interested par- ties Shall not be in- Ease of disper- sion ferior to that of the agreed refer- See clause 10 ence Pigment (see 4.3.2) Oil absorption value Shall not differ by more than 10 % from the value agreed be- tween the inter- ested Parties ISO 787-5 7 Determination of sum of iron(ll) and iron(lll) ions (basic iron content) and of hexacyanoferrate complex content For the determination of the basic iron content and hexacyanoferrate complex content, two methods are provided. Method A (7.1) shall be used as the referee method in cases of dispute. NOTE 3 lt is recommended that mercury be removed from the waste solutions before discharge to efffuent drains. A suggested procedure is given in annex A. 7.1 .l Principle A test Portion is decomposed by cold aqueous pot- assium hydroxide Solution to form insoluble iron hy- droxide and soluble potassium hexacyanoferrate(lI). The iron hydroxide is dissolved in hydrochloric acid. The iron(l ll) is reduced to iron(lI) with tin(lI) chloride Solution and the iron(ll) is titrated with potassium dichromate Solution, using barium diphenylamine sulfonate as indicator. The potassium cyanoferrate( II) is oxidized to cyanoferrate(lII) with potassium permanganate sol- ution. Then potassium iodide Solution is added and the iodine liberated is titrated with sodium thiosulfate Solution. 7.1.2 Reagents During the analysis, use only reagents of recognized analytical grade and only water of at least grade 3 purity as defined in ISO 3696. WARNING - Use the reagents in accordance with the appropriate health and safety regulations. 7.1.2.1 Hydrochlorit acid, concentrated, approxi- mately 37 % (m/m), p z 1 ,19 g/ml. 7.1.2.2 Hydrochlorit acid, diluted 1 + 1. Add 1 part by volume of the concentrated hydroc acid (7.1.2.1) to 1 part by volume of water. 1 loric 7.1.2.3 Mixture of sulfuric and orthophosp acids. ioric Mix 310 ml of concentrated sulfuric acid [approximately 96 % (m/m), p N 1,84 g/ml)] carefully with 250 ml of concentrated orthophosphoric acid IH,PO,) [approximately 85 % (m/m), p z 1,70 g/ml]. Add the resultant mixture slowly to about 400 ml of water and then dilute with water to 1 litre. 3 SIST EN ISO 2495:2001

ISO 2495:1995(E) 7.1.2.4 Potassium hydroxide Solution, 10 % (m/m). 7.1.2.5 Potassium iodide solution, 10 % 7.1.2.6 Sodium acetate Solution. Dissolve 500 g of crystalline sodium acetate in 1 000 ml of water. 7.1.2.7 Mercury(ll) chloride, saturated Solution (60 g/l to 100 g/l). 7.1.2.8 ‘bin(H) chloride, 100 g/l Solution. Dissolve 50 g of SnCI,-2H,O in 300 ml of concen- trated hydrochloric acid (7.1.2.1) and dilute with water to 500 ml. Keep the solut ion clear by storing it in closed f Ia sk CO ntaining a lit tle metallic t a hermeticaliy in. 7.1.2.9 Sodium thiosulfate, Standard volumetric solution, +a,S,O,) = 0,l moljl. 7.‘L2.10 Potassium permanganate, Standard volu- metric Solution, c(1/5 KMnO,) = 0,l mol/l. 7.‘l.2.11 Potassium dichromate, Standard volu- metric Solution, c(l/6 K,Gr,O,) = 0,l mol/l. 7.1.2.12 Zinc sulfate solution. Dissolve 25 g of ZnS0,.7H,O in 100 ml of water. 7.1.2.13 Barium diphenylamine sulfonate indi- cator. Prepare a 0,4 % (m/m) aqueous Solution of barium diphenylamine sulfonate and filter the Solution. 7.1.2.14 Starch, dissolved in hot water to give a IO g/S solution, or powdered starch soluble in cold water (for example, that known as Zulkowsky starch is soluble). 7.1.3 Apparatus Use ordinary laboratory apparatus and glassware complying with the requirements of ISO 385-1, to- gether with the following: 7.1.3.1 Filter funnel. a I Of GEI paCit\J 1 500 ml. 7.1.4 Procedure 7.1.4.1 Preliminary treatment of the test portion Carry out the determination in duplicate. Weigh, to the nearest 1 mg, approximately 1 g of the Sample (see clause 5) into a 100 ml beaker. Add 20 ml of the potassium hydroxide Solution (7.1.2.4). Stir the mixture carefully with a glass rod with a flat- tened end and allow to stand for 2 h. From time to time lightly grind any residue on the bottom of the beaker with the glass rod. When all the iron blue Pigment is decomposed, filter the mixture through the filter funnel (7.1.3.1), containing a medium filter Paper, and wash the beaker, glass rod and residue repeat- edly with water until the washings are colourless and neutral. Add the washings ‘to the fiitrate. Use the residue obtained for the determination of the sum of iron(ll) and iron(lll) ions (basic iron content) (7.1.4.2) and the filtrate for the determination of the hexacyanoferrate complex content (7.1.4.3). 7.1.4.2 Determination of sum of iron(ll) and iron(lll) ions (basic iron content) Extract the residue on the filter Paper with hot 1 + l hydrochloric acid (7.1.2.2), collecting the extract in a conical flask and keeping the total volume as small as possible. NOTE 4 lf the acid extract is coloured blue, it is an indi- cation that the residue has not been properly washed and the determination should be repeated with another 1 g of the Sample. Heat the Solution to boiling and add the tin(ll) chloride Solution (7.1.2.8) drop by drop until the Solution is just colourless; then add two drops in excess. Keep the Solution hot during the addition of the tin(ll) chloride. Cool the Solution rapidly to room temperature, add 5 ml of the mercury(ll) chloride Solution (7.1.2.7), mix weil and wash down the sides of the flask with cold water. Allow the Solution to stand for 1 min and add 40 ml of the sulfuric/orthophosphoric acid mixture (7.1.2.3). Dilute the Solution with water to 100 ml to 200 ml according to the amount of iron present. Add 0,2 ml to 0,4 ml of the barium diphenylamine sulfonate indicator (7.1.2.13) and titrate with the pot- assium dichromate solution (7.1.2.11) until the sol- ution begins to darken. Complete the titration by adding the potassium dichromate solutian di-cp bi/ drop unti1 a permanent vioiet ~oiour is obtained, Sub- trayt 0, 1 rni from the titration figure for each 0,7 mi of the indicator Solution used. SIST EN ISO 2495:2001

0 ISO ISO 2495:1995(E) 7.1 A.3 Determination of hexacyanoferrate 7.1.5.2 Hexacyanoferrate complex content complex content 7.1.5.2.1 Calculation Transfer the filtrate obtained as described in 7.1.4.1 to the stoppered flask or bottle (7.1.3.2), dilute to 800 ml with water and add 30 ml of the hydrochloric acid (7.1.2.1) and 90 ml of the sodium acetate Solution (7.1.2.6). Add the potassium permanganate Solution (7.1.2.10) in excess, i.e. until a distinct red-brown col- our is obtained and the turbidity first formed has dis- appeared. Then add 20 ml of the potassium iodide Solution (7.1.2.5) and allow the mixture to stand for 4 min. Titrate the iodine liberated by the excess of Calculate the hexacyanoferrate complex content w[Fe(CN),] of the Pigment, expressed as a percent- age by mass, using the equation v2 x 2,119 x Io-* 100 X = m1 permanganate with the sodium thiosulfate Solution (7.1.2.9). m1 is the mass, in grams, of the test Portion; is the volume, in millilitres, of the sodium thiosulfate Solution (7.1.2.9) used in the second titration (see note 5); Add to the Solution 20 ml of the hydrochloric acid (7.1.2.1), 20 ml of the potassium iodide Solution (7.1.2.5) and 20 ml of the zinc sulfate Solution (7.1.2.12) and allow the turbid mixture to stand for 3 min. Add either 50 mg of the cold-water-soluble starch or 3 to 4 drops of the starch Solution (7.1.2.14) and titrate the liberated iodine with the sodium thiosulfate Solution (7.1.2.9). Record the vol- ume of sodium thiosulfate Solution used (V2). 2,119 x lo-2 is the factor for the conversion of millilitres of sodium thiosulfate Solution to grams of [Fe(CN),]. NOTE 5 The volume of sodium thiosulfate Solution re- quired in the second titration is used in the calculation. If the volume required in the first titration (i.e. the differente be- tween the permanganate and thiosulfate figures) is used, the calculated result may be higher than the true value due to interference by traces of organic matter present, the Oxidation of which by the permanganate would increase the apparent hexacyanoferrate complex content. 7.1.5 Expression of results 7.1.5.1 Sum of iron(ll) and iron(lll) ions (basic iro
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