BS-EN-ISO-787-18-1995.pdf

BRITISH STANDARD BS EN ISO 787-18:1995 General methods of test for pigments and extenders Part 18: Determination of residue on sieve Mechanical flushing procedure ICS: 87.060.10; 87.060.30 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 787-18:1995 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 December 1995 © BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference STI/1 Draft announced in BSI News November 1995 ISBN 0 580 24118 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee STI/1, Pigments, upon which the following bodies were represented: British Cement Association British Coatings Federation Ltd. British Colour Makers Association British Precast Concrete Federation Ltd. Cement and Concrete Pigment Suppliers Association China Clay Association Oil and Colour Chemists Association Titanium Pigment Manufacturers Technical Committee Zinc Development Association Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 787-18:1995 © BSI 12-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 0Introduction3 1Scope and field of application3 2References3 3Definition3 4Principle3 5Materials3 6Apparatus3 7Sampling4 8Procedure4 9Expression of results4 10Test report5 Figure Mechanical flushing apparatus5 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 787-18:1995 ii © BSI 12-1999 National foreword This Part of BS EN ISO 787 has been prepared by Technical Committee STI/1. It is identical with ISO 787-18:1983 General methods of test for pigments and extenders Part 18: Determination of residue on sieve Mechanical flushing procedure published by the International Organization for Standardization (ISO). In 1995 the European Committee for Standardization (CEN) accepted ISO 787-18:1983 as European Standard EN ISO 787-18:1995. As a consequence of implementing the European Standard this British Standard is dual-numbered as BS EN ISO 787-18:1995, BS 3483-B12:1995. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred toCorresponding British Standard ISO 787-7:1981BS 3483 Methods for testing pigments for paints Part B3:1982 Determination of residue on sieve (water method, using a manual procedure) ISO 842:1984BS 4726:1986 Methods for sampling raw materials for paints and varnishes Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN ISO title page, pages 2 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN ISO 787-18 August 1995 ICS 87.060.10; 87.060.30 Descriptors: Paints, pigments, determination, sieve residues English version General methods of test for pigments and extenders Part 18: Determination of residue on sieve Mechanical flushing procedure (ISO 787-18:1983) Méthodes générales dessai des pigments et matières de charge Partie 18: Détermination du refus sur tamis Méthode mécanique avec liquide dentraînement (ISO 787-18:1983) Allgemeine Prüfverfahren für Pigmente und Füllstoffe Teil 18: Bestimmung des Siebrückstandes Mechanisches Spülverfahren (ISO 787-18:1983) This European Standard was approved by CEN on 1995-03-23. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard 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 Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members. Ref. NO. EN ISO 787-18:1995 E Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 787-18:1995 © BSI 12-1999 2 Foreword The text of the International Standard from ISO/TC 35, Paints and varnishes, of the International Organization for Standardization (ISO) has been taken over as a European Standard by the Technical Committee CEN/TC 298, Pigments and extenders. 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 February 1996, and conflicting national standards shall be withdrawn at the latest by February 1996. According to CEN/CENELEC International Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 787-18:1995 © BSI 12-19993 0 Introduction This document is a part of ISO 787, General methods of test for pigments and extenders. 1 Scope and field of application 1.1 This part of ISO 787 specifies a general method for determining the residue on a sieve from a sample of pigment or extender dispersed in water, using a mechanical flushing procedure. This method can also be applied to the examination of other powders or granules which are insoluble in water. It is neither applicable to hydrophobic nor pelletized pigments and extenders. 1.2 ISO 787-7 specifies a general method of test for determining the residue on a sieve from a sample of pigment or extender dispersed in water, using a manual procedure. 1.3 For most pigments and extenders, these two test methods will give different results, and it is therefore essential to state clearly in a specification which method is to be used, and in the test report, which method has been used. NOTEWhen either of these general methods is applicable to a given pigment or extender, only a cross-reference to it should be included in the International Standard relating to that pigment or extender, with a note of any detailed modification which may be needed in view of the special properties of the material under consideration. Only when neither of these general methods is applicable to a particular material a special method for determination of residue on sieve should be specified. 2 References ISO 565, Test sieves Woven metal wire cloth, perforated plate and electroformed sheet Nominal sizes of openings1). ISO 787-7, General methods of test for pigments and extenders Part 7: Determination of residue on sieve Water method Manual procedure. ISO 842, Raw materials for paints and varnishes Sampling. 3 Definition residue on sieve (R) the coarse particles which remain on a sieve of a specified nominal aperture when a test is performed in accordance with this International Standard 4 Principle In the test apparatus, the pigment or extender under test, dispersed in water, is brought into centrifugal motion by a system of rotating jets of water. The water flushes the fine particles through the sieve, the coarse particles being retained on the sieve. The residue on the sieve is dried and weighed. 5 Materials 5.1 Filtered tap water, at a pressure of 300 ± 20 kPa above atmospheric. 5.2 Wetting agents, such as ethanol 95 % (V/V) or sulphonates, etc., for pigments and extenders that are difficult to wet with water. The selection of an appropriate wetting agent shall be agreed between the parties, and the wetting agent used shall be stated in the test report. 6 Apparatus Ordinary laboratory apparatus and 6.1 Mechanical flushing apparatus (see the Figure) consisting of the following items. 6.1.1 Container 6.1.2 Cover, with protective hood, driving motor, hollow shaft with two nozzles with an internal diameter of 1 ± 0,2 mm, head with three nozzles of diameter 1 ± 0,2 mm, water supply connection, filling funnel, handle and overflow. NOTEWith the specified pressure and internal diameter of the nozzles the water flow will be about 5 l/min. It is recommended that the internal diameter of the nozzles should be periodically examined. Calcareous deposits should be dissolved by chemical substances which do not attack the material of the nozzles. The cleaning should not be performed by mechanical means. 6.1.3 Sieve, consisting of a frame of metal or plastics material with a wire gauze of phosphor-bronze or stainless steel. The nominal mesh aperture shall be selected from the principal sizes specified in ISO 565 and shall be stated in the test report. NOTE 1Sieves may also be used in which three breaker lugs for dispersal of agglomerates project into the plane of the sieve. NOTE 2Sieves of nominal mesh aperture of 45 4m are frequently used. It is recommended that the mesh apertures of the sieve should be periodically examined to check whether the mesh aperture of the sieve has been damaged, for example by the water jet or by heat. The sieve should be discarded if the mesh apertures have been affected. NOTE 3If a sieve with a plastics frame is used, care should be taken that the softening point of the plastics material is well above the temperature used for drying the residue. Sieves with a plastics frame should be heated at 105 °C to constant mass before being used for the first time. 1) At present at the stage of draft. (Revision of ISO 565:1972.) Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 02:58:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 787-18:1995 4 © BSI 12-1999 6.1.4 Sieve holder 6.2 Oven, capable of being maintained at 105 ± 2 °C. 6.3 Balance, accurate to at least 0,1 mg. 6.4 Desiccator, containing an efficient desiccant. 7 Sampling Take a representative sample of the material to be tested as described in ISO 842. 8 Procedure Carry out the determination in duplicate. 8.1 Test portion Weigh, to the nearest 0,1 %, into a beaker of suitable capacity, a quantity of the sample, m0, such that a sufficient residue on the sieve (6.1.3) is obtained. Generally, a test portion of 5 to 50 g is necessary, but in the case of products yielding a very low residue on the sieve a greater test portion, up to 300 g, should be used. 8.2 Preparation of the dispersion Disperse the test portion (8.1) in a suitable quantity of water in a beaker by stirring with a glass rod to give a free-flowing suspension. If the test portion is not readily wetted by water, use a wetting agent (5.2). NOTEA slowly rotating paddle stirrer may be used, but do not use high power stirrers as these may cause the de-aggregation of pigment particles. 8.3 Determination 8.3.1 Adjust the flow of the water of the mechanical flushing apparatus (6.1) so that the water pressure is 300 ± 20 kPa above atmospheric, and switch on the motor. Transfer the suspension quantitatively, by way of the funnel (see the Figure), to the apparatus and rinse the beaker and funnel with water. Record the time when the fine particles have almost completely passed through the sieve as indicated by the noise of the water passing through the nozzles becoming louder, hissing sharply and then remaining constant, while at the same time the water running through the sieve appears to be clear. Continue flushing for a further 10 min (see note 1) in order to break agglomerates by the now fully active water jet and to rinse the last fine particles through the sieve (see note 2). NOTE 1For some pigments a flushing duration of 10 min is not necessary. With such pigments the required duration should be determined by preliminary experiments and if a period shorter than 10 min is used this should be stated in the test report. NOTE 2If the flushing water is very hard, it is advisable to give the apparatus a final rinse with distilled water in order to prevent the formation of deposits of calcium salts on the sieve on drying. 8.3.2 Switch off the motor, and then stop the water flow. Remove the sieve from the test apparatus and dry it in the oven (6.2) at 105 ± 2 °C (see the note) for 1 h. Allow the sieve and residue to cool in the desiccator (6.4) and weigh to the nearest 0,1 mg (m1). Remove the residue from the sieve using a fine brush and weigh the empty sieve to the nearest 0,1 mg (m2). NOTEIf the melting point of the residue on the sieve is lower than 110 °C, a more suitable drying temperature should be used and this should be stated in the test report. 8.3.3 If the duplicate determinations differ by more than 0,1 % absolute, repeat the procedure. If the two further determinations still differ by more than 0,1 % absolute, state all four values in the test report, and check the product for inhomogeneity. 8.4 Examination of the residue Inspect the residue for the presence of incompletely dispersed pigment or extender and, if present, repeat the whole procedure (clause 8) using an alternative dispersing agent agreed between the parties. If the residue contains extraneous matter, report its presence and nature. 9 Expression of results Calculate the residue on sieve (mechanical flushing procedure) by the equation where Ris the residue on sieve, expressed as a percentage by mass; m0is the mass, in grams, of the test portion; m1is the mass, in grams, of the sieve with residue; m2is the mass, in grams, of the empty sieve. Report the mean of the duplicate determinations if they agree to within 0,1 % absolute. If not, see 8.3.3. If the result with the 100 g test portion is less than 0,01 % this should be stated in the test report