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1、nternationa Standard 787118 ,NTERNAT,ONAL ORGANlZATlON FOR STANDARDIZATION*MEXflYHAPO,!,HAfl OPrAHti3AUWR flOCTAHAPTbl3AUM.ORGANlSATlON INTERNATIONALE DE NORMALISATION General methods of test for pigments and extenders - Part 18 : Determination of residue on sieve. - Mechanical flushing procedure M
2、9 Descriptors : paints, pigments, determination, sieve residues. Price based on 4 pages Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of developing International Standards is carried out through
3、IS0 technical committees. Every member body interested in a subject for which a technical committee has been authorized 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. Draft Internatio
4、nal Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 787/18 was developed by Technical Committee ISO/TC 35, Paints and varnishes, and was circulated to the
5、member bodies in November 1980. It has been approved by the member bodies of the following countries : Austria Belgium Brazil Canada China Czechoslovakia Egypt, Arab Rep. of Germany, F. R. Hungary Ireland Israel Italy Kenya Korea, Dem. P. Rep. of Korea, Rep. of Mexico Netherlands Norway Poland Portu
6、gal Romania South Africa, Rep. of Spain Sweden Switzerland United Kingdom USSR The member body of the following country expressed disapproval of the document on technical grounds : France This International Standard cancels and replaces IS0 787/XVlll-1973, of which it con- stitutes a technical revis
7、ion. 0 International Organization for Standardization, W83 0 Printed in Switzerland ii -,-,- The purpose of this International Standard is tp establish a series of general test methods for pigments and extenders which are suitable for all or many of the individual pigments and extenders for which sp
8、ecifications might be required. In such cases, a cross-reference to the general method should be included in the International Standard relating to that pigment or extender, with a note of any detailed modifications which might be needed in view of the special properties of the product in question.
9、Technical Committee ISO/TC 35, Paints and varnishes, decided that all the general methods should be published as they become available, as parts of a single Interna- tional Standard, in order to emphasize the relationship of each to the whole series. The Technical Committee also decided that, where
10、two or more procedures were widely used for determining the same or a similar characteristic of a pigment or ex- tender, there would be no objection to including more than one of them in the IS0 series. In such cases it will, however, be essential to state clearly in a specification which method is
11、to be used and, in the test report, which method has been used. Parts of the series already published are as follows : Part 1 : Comparison of colour of pigments Part 2 : Determination of matter volatile at 105 C Part 3 : Determination of matter soluble in water - Hot extraction method Part 4 : Deter
12、mination of acidity or alkalinity of the aqueous extract Part 5 : Determination of oil absorption value Part 7 : Determination of residue on sieve - Water method - Manual procedure Part 8 : Determination of matter soluble in water - Cold extraction method Part 9 : Determination of pH value of an aqu
13、eous suspension Part IO : Determination of density - Pyknometer method Part 11 : Determination of tamped volume and apparent density after tamping Part 13 : Determination of water-soluble sulphates, chlorides and nitrates Part 14 : Determination of resistivity of aqueous extract Part 15 : Comparison
14、 of resistance to light of coloured pigments of similar types Part 16 : Comparison of relative tinting strength (or equivalent colouring value) and colour on reduction in linseed stand oil using the automatic muller Part 17 : Comparison of lightening power of white pigments Part 18 : Determination o
15、f residue on sieve - Mechanical flushing procedure Part 19 : Determination of water-soluble nitrates - Salicylic acid method Part 20 : Comparison of ease of dispersion - Oscillatory shaking method Part 21 : Comparison of heat stability of pigments using a stoving medium Part 22 : Comparison of resis
16、tance to bleeding of pigments Part 23 : Determination of density (using a centrifuge to remove entrained air) Part 24 : Determination of relative tinting strength of coloured pigments and relative scattering power of white pigments - Photometric method iii -,-,- INTERNATIONAL STANDARD IS0 787/18-198
17、3 (E) General methods of test for pigments and extenders - Part 18 : Determination of residue on sieve - Mechanical flushing procedure 0 Introduction This document is a part of IS0 787, Generalmethods of test for pigments and extenders. 1 Scope and field of application 1.1 This part of IS0 787 speci
18、fies a general method for de- termining 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 hyd
19、rophobic nor pelletized pigments and extenders. 1.2 IS0 787/7 specifies a general method of test for de- termining 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
20、 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. NOTE - When either of these general methods is applicable to a given pigment or extender, only a cross-reference to it should be included in the
21、 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 det
22、ermination of residue on sieve should be specified. 2 References IS0 565, Test sieves - Woven metal wire cloth, perforated plate and electroformed sheet - Nominal sizes of openings. 1) IS0 78717. General methods of test for pigments and ex- tenders - Part 7 : Determination of residue on sieve - Wate
23、r method - Manual procedure. IS0 842, Raw materials for paints and varnishes - Sampling. 1) At present at the stage of draft. (Revision of IS0 565-1972.) 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 accor
24、dance 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 par- ticles through the sieve, the coarse particles being retained o
25、n 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 a
26、ppropriate 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) con- sisting of the following items. 6.1.1 Container. 6.1.2 Cover, with protec
27、tive hood, driving motor, hollow shaft with two nozzles with an internal diameter of 1 + 0,2 mm, head with three nozzles of diameter 1 f 0,2 mm, water supply connection, filling funnel, handle and overflow. NOTE - With the specified pressure and internal diameter of the nozzles the water flow will b
28、e about 5 Urnin. It is recommended that 1 IS0 787/18-1983 (El 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
29、. 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 IS0 565 and shall be stated in the test report. NOTES 1 Sieves may also be used in which three
30、 breaker lugs for dispersal of agglomerates project into the plane of the sieve. 2 Sieves of nominal mesh aperture of 45 urn 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, f
31、or example by the water jet or by heat. The sieve should be discarded if the mesh apertures have been affected. 3 If 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
32、plastics frame should be heated at 105 OC to constant mass before being used for the first time. 6.1.4 Sieve holder. NOTES 6.2 Oven, capable of being maintained at 105 f 2 OC. 6.3 Balance, accurate to at least 0,l mg. 6.4 Desiccator, containing an efficient desiccant. suspension. If the test portion
33、 is not readily wetted by water, use a wetting agent (5.2). NOTE - A 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
34、.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
35、 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 ag
36、glomerates by the now fully active water jet and to rinse the last fine particles through the sieve (see note 2). 1 For 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
37、10 min is used this should be stated in the test report. 2 If the flushing water is very hard, it is advisable to give the apparatus a final rinse with distilled water in order to prevent the for- mation of deposits of calcium salts on the sieve on drying. 7 Sampling Take a representative sample of
38、the material to be tested as described in IS0 642. 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 OC (see the note) for 1 h. Allow the sieve and residue to cool in the desiccator (6.4) and weigh to the neares
39、t 0,l mg (ml). Remove the residue from the sieve using a fine brush and weigh the empty sieve to the nearest 0,l mg (m2). NOTE - If the melting point of the residue on the sieve is lower than 110 OC, a more suitable drying temperature should be used and this 8 Procedure Carry out the determination i
40、n duplicate. 8.1 Test portion Weigh, to the nearest 0,l %, into a beaker of suitable capacity, a quantity of the sample, ma, 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 o
41、n 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 2 should be stated in the test report. 8.3.3 If the duplicate determinati
42、ons differ by more than 0,l % absolute, repeat the procedure. If the two further deter- minations still differ by more than 0,l % absolute, state all four values in the test report, and check the product for in- homogeneity. 8.4 Examination of the residue Inspect the residue for the presence of inco
43、mpletely dispersed pigment or extender and, if present, repeat the whole pro- cedure (clause 8) using an alternative dispersing agent agreed between the parties. If the residue contains extraneous matter, report its presence and nature. IS0 787/18-1983 (E) 9 Expression of results Calculate the resid
44、ue on sieve (mechanical flushing procedure) by the equation R = (ml - m2) x loo mo IO Test report The test report shall contain at least the following information : a) the type and identification of the product tested; b) a reference to this International Standard (IS0 787/18); c) the result of the
45、test as indicated in clause 9; where d) the nominal mesh aperture of the sieve used; R is the residue on sieve, expressed as a percentage by mass; m. is the mass, in grams, of the test portion; ml is the mass, in grams, of the sieve with residue; m2 is the mass, in grams, of the empty sieve. Report
46、the mean of the duplicate determinations if they agree to within 0,l % absolute. If not, see 8.3.3. If the result with the 100 g test portion is less than 0,Ol % this should be stated in the test report as “less than 0,Ol %“. e) the mass of the test portion; f) if used, the type and quantity of the
47、wetting agent; g) a description of the type and condition of the residue on sieve (for example extraneous matter); h) any deviation, by agreement or otherwise, from the procedure specified (see note 1 to 6.1.3, note 1 to 8.3.1 and note to 8.3.2); j) the date of the test. 3 IS0 787/18-1983 (El Dimens
48、ions in millimetres 3 G t% x m P 5 E $ r g Protective hood Filling funnel -, Water supply t connection 7 Hollow shaft - with nozzles Lq wo nozzles, Q 1 Three nozzles, 1 Sieve holder i 3 Handle and safety overflow Test sieve Test sieve (breaker lug type) Figure - Mechanical flushing apparatus 4 -,-,-