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1、B-6:1! ndat- ents to iI rece lemk ently st fc ninal meni gmel ermi - MI on c - MI eristr in - MI eristr finen - MI erisfl oss. INTERNATIONAL STANDARD IS0 8780-6 First edition 1990-11-15 pigments of medium binder demand -. pigment concentration 40 % (m/m); pigments of high binder demand - pigment con
2、- centration 25 % (m/m). Procedure 8.1 Test portion For the apparatus specified in 4.1, the mass of the mill base shall be not less than 50 g. If the criterion for assessing the dispersion charac- teristics is to be the evaluation of the development of tinting strength (see IS0 8781-l), the masses o
3、f the pigment and of the binder system shall be de- termined to within 0,s %. For other methods of as- sessment (for example fineness of grind, see IS0 8781-2, and change of gloss, see IS0 8781-3), wider tolerance ranges may be agreed on. 2 Copyright International Organization for Standardization Pr
4、ovided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:32:54 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8780-6:1990( E) 8.2 Pre-mixing Thoroughly mix the agreed amounts of pigment and binder system with the
5、 spatula (4.2). Pre-heat the rolls of the triple-roll mill (4.1) to an agreed temper- ature and set the first and second roll at the lowest pressure setting, leaving the third roil clear. Load the mill base on to the first roll, switch on the triple-roll mill and mix until a homogeneous disper- sion
6、 has been obtained. NOTE 4 The pre-mixing time will depend on the type and quantity of mill base. For 50 g of mill base, 2 min is generally sufficient. Alternatively, by agreement between the interested parties, the pre-mixing can be carried out using a high-speed impeller mill (see IS0 8780-3) or o
7、ther suitable equipment. In this case, load the pre-mixed mill base on to the first roll of the triple-roll mill as in the above pre-mixing procedure, ensuring that its temperature is slightly below that of the pre-heated rolls. 8.3 Dispersion With the rolls still rotating following pre-mixing, set
8、them to produce friction, i.e. set the roll contact forces at levels appropriate to the viscosity of the mill base (so that the second and third rolls have a thin, uniform coating of mill base on them). Contact between rolls one and two shall be adjusted first and the third roll adjusted last (so th
9、at at no time is there metal-to-metal roll contact). A pass is deemed to have been completed when the first roll is almost dry, just before the last of the mill base has passed the middle roll. Any material which runs off the sides of rolls shall be discarded as it may be either contaminated or not
10、properly dis- persed. The appropriate roll contact force shall be deter- mined by preliminary experiments and shall be agreed on between the interested parties. If two or more pigments are to be compared, adjust the temperature of the prepared mill bases contain- ing the individual pigments to withi
11、n 2 “C. Collect the mill base from the apron of the machine in a suitable container and mix thoroughly with the spatula. The ease of dispersion may be evaluated either by measuring, in accordance with IS0 1524, the fineness of grind of the material after one pass through the mill or by making one or
12、 more additional passes, taking portions of the dispersion after each pass and assessing their dispersion characteristics by one of the methods specified in IS0 8781. 8.4 Stabilization If necessary, for example if the mill base is not sta- ble enough, stabilize each test portion after its re- moval
13、from the mill base by adding, for example, more binder and/or special additives. The procedure shall be agreed on between the interested parties. In contrast to low-viscosity mill bases (for which an oscillatory shaking machine, a bead mill or a high- speed impeller mill, for instance, may be used)
14、sta- bilization is of minor importance. 9 Test report The test report shall contain at least the following information: a) all details necessary to identify the product tested; b) a reference to this part of IS0 8780; c) the items of supplementary information referred to in annex A; d) the solvent (
15、if any); e) the method and time of pre-mixing (see 8.2); f) the roll contact force, temperature of the thermostatic fluid and number of passes (see 8.3): g) any deviation from the procedure specified; h) the date(s) of the test. 3 Copyright International Organization for Standardization Provided by
16、IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:32:54 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8780-6:1990(E) Annex A (normative) Required supplementary information The items of supplementary information lis
17、ted in this b) annex shall be supplied as appropriate to enable the method to be carried out. The information required should preferably be agreed between the interested parties and may be derived, in part or totally, from an international or national standard or other document related to the produc
18、t under test. a) Type and complete details (see 4.1) of the triple- roll mill. cl d) e) 9 Binder system (see clause 5). Composition of the mill base (see clause 7) and its temperature (see 8.3). Conditions of pre-mixing (see 8.2). Conditions of dispersion (see 8.3). Stabilization procedure (see 8.4)
19、. 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:32:54 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8780-6:1990(E) UDC 667.622:541 .I 6.052
20、:542.22 Descriptors: paints, pigments, extenders, dispersibility, dispersing. Price based on 4 pages - Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:32:54 MDTNo reproduction or networking permitted without license from IHS -,-,-