《ISO-8780-2-1990.pdf》由会员分享，可在线阅读，更多相关《ISO-8780-2-1990.pdf（8页珍藏版）》请在三一文库上搜索。
1、INTERNATIONAL STANDARD IS0 8780-2 First edition 1990-l 1-15 PI Internat Dot Se6 Pigments and extenders - Methods of dispersion for assessment of dispersion characteristics - Part 2: Dispersion using an oscillatory shaking machine Pigments et m - the mean time-weighted position of the contain- ers is
2、 vertical. The design shown in figure? meets these require- ments. 4.3 Containers, of a suitable type. Containers for the mill bases shall be of the same size and type as those used for the agreed reference pigments. Dimensions in millimetres 6-B Backwards and forwards movement 2 Copyright Internati
3、onal Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 19:18:34 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8780-2:1990(E) Examples of suitable types are 250 ml glass or
4、polyethylene bottles with screw caps lined with polyethylene inserts. The size and type of container shall be agreed on and shall be recorded in the test report. 4.4 Grinding spheres, of a suitable type. Spheres of the same size and type shall be used for all the mill bases under simultaneous test.
5、The type, mean diameter and density shall be agreed on and shall be recorded in the test repot-t. If the spheres have never been used, they shall be conditioned by shaking them in a mill base (see 7.1), for example for 60 min, and cleaned. NOTE 2 The diameter, density and total mass of the grinding
6、spheres have a significant effect on the disper- sion obtained. Glass spheres of a mean diameter of 3 mm + 0,5 mm and a density of 2,6 g/cm3 + 0,2 g/cm3 have been found to be suitable. 5 Binder system The binder system shall be agreed on between the interested parties. The test report shall state th
7、e binder, the solvent and the concentration of the binder in the solvent, as well as giving information on the rheological properties (for example, viscosity or flow time) of the binder system. The same batch of binder system shall be used for all tests in the same series. 6 Sampling b) pigments of
8、medium binder demand - pigment concentration IO % (m/m) to 40 % (l?z/m); c) pigments of high binder demand - pigment con- centration lower than 10 % (m/m). 7.2 Volume The mill base shall occupy approximately 30% of the volume of the container (4.3). The mass of the pigment and of the binder system m
9、ay be deter- mined by using the following equations: Mass, mp, of pigment, in grams: 0,3 x v mp= + 100 - PC PM x pc Mass, mM, of binder system, in grams: mp x (100 - PC) mM = _ PC where PC is the pigment concentration in the mill base, expressed as a percentage by mass: V is the volume, in millilitr
10、es, of the con- tainer (4.3); PM is the density, in grams per cubic centi- metre, of the binder system; PP is the density, in grams per cubic centi- metre, of the pigment, determined by one of the procedures described in IS0 787-10. Take a representative sample of the product to be tested, as descri
11、bed in IS0 842. 8 Volume of grinding spheres 7 Mill base 7.1 Composition The viscosity of a mill base depends on the binder demand of the pigment and its concentration in a given binder system. Preliminary experiments shall therefore be carried out to ascertain a suitable mill base composition. The
12、viscosity of the mill base during dispersion shall be such that the grinding spheres can move freely (see clause 1). This can be checked by shaking the containers manually. For binder systems with flow times of 20 s to 40 s, determined with flow cup IS0 2431 No. 6, the follow- ing pigment concentrat
13、ions have been found to be suitable as starting points: a) pigments of low binder demand - pigment con- centration higher than 40 % (m/m); The apparent volume of the grinding spheres (see note 2) shall be approximately 50% of the total vol- ume of the container. The same volume of grinding spheres s
14、hall be used in all tests in the same series. 9 Procedure 9.1 Filling the containers Unless otherwise agreed or found advisable (see note 3), weigh the grinding spheres (4.4) into the container (4.3). Add the required mass of binder system (Q,), calculated in accordance with 7.2. Wet the grinding sp
15、heres with the binder system by tilt- ing the container. Then add the required mass of pigment (mp), calculated in accordance with 7.2. Close the container. Wet the pigment by carefully tilting the container. 3 Copyright International Organization for Standardization Provided by IHS under license wi
16、th ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 19:18:34 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8780-2:1990(E) NOTE 3 If it is difficult to wet the pigment, it may be advisable to select a different sequence of preparing the con
17、tainers and, if necessary, the mill base may be placed in the container first and stirred with a spatula prior to the addition of the grinding spheres. The total mass of these test portions shall not ex- teed 15 % of the initial mass of the mill base. Oth- erwise make separate dispersions for each t
18、ime interval. Complete the preparation of the full set of mill bases as quickly as possible in order to avoid differences in stirring or wetting time between the samples. If the criterion for assessing the dispersion charac- teristics is to be the evaluation of the development of tinting strength (s
19、ee IS0 8781-l), the masses of the pigment and of the binder system shall be de- termined to within 0,5 %. 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. 9.2 Dispersion Immediately after
20、the last mill base has been pre- pared, place the containers in the holder (4.2) and clamp the assembly in the paint-conditioning ma- chine (4.1). NOTE 4 The intensity of the shaking process depends on the loading of the holder. If repeatable dispersion re- sults are to be obtained, particularly in
21、the case of two- armed shaking machines, the holders should be equally loaded. Take test portions of the dispersion after each of several (agreed) shaking times. At least four shak- ing times shall be selected from the following: 9.3 Stabilization If necessary, for example if the mill base is not st
22、a- ble enough, stabilize each test portion after its re- moval from the mill base by adding, for example, more binder and/or special additives. The procedure shall be agreed on between the interested parties. 9.4 De-aeration If necessary, allow any air bubbles within the test portions to escape befo
23、re proceeding to assess the dispersion. The means by which this is achieved, for example by allowing to stand for a few minutes, shall be agreed on between the interested parties. 10 Test report The test report shall contain at least the following information: a) all details necessary to identify th
24、e product tested: b) a reference to this part of IS0 8780; c) the items of supplementary information referred to in annex A; - pigments with poor ease of dispersion - 5 min, 10 min, 20 min, 40 min, 80 min, 160 min; d) any deviation from the procedure specified; e) the date(s) of the test. - pigments
25、 with high ease of dispersion - 1 min, 2 min, 4 min, 8 min, 16 min, 32 min. 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 19:18:34 MDTNo reproduction or networking permitted
26、without license from IHS -,-,- IS0 8780-2:1990(E) Annex A (normative) Required supplementary information The items of supplementaty information listed in this annex shall be supplied as appropriate to enable the method to be carried out. The information required should preferably be agreed between t
27、he interested parties and may be derived, in part or totally, from an international or national standard or other document related to the product under test. a) Type of machine (see 4.1). b) Type of holder (see 4.2) c) Type and size of container (see 4.3). d) Type, mean diameter, density and total m
28、ass of the grinding spheres (see 4.4). e) Binder system (see clause 5) f) Composition of the mill base (see 7.1). g) Shaking times (see 9.2). h) Stabilization procedure (see 9.3). i) De-aeration procedure (see 9.4). Copyright International Organization for Standardization Provided by IHS under licen
29、se with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 19:18:34 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8780-2:1990(E) UDC 667.622:541 .I 8.052:542.22 Descriptors: paints, pigments, extenders, dispersibility, dispersing. Price based on 5 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 19:18:34 MDTNo reproduction or networking permitted without license from IHS -,-,-