ASTM D6336-11(R2021) pdf free download
ASTM D6336-11(R2021) pdf free download.Standard Practice for Evaluation of Flushing Vehicles for Pigment Wetting Using a Vacuum Modified Sigma Blade Mixer
1. Scope
1.1 This practice covers guidelines for the evaluations of flushing vehicles for pigment dispersion using a vacuum modified sigma blade mixer, or vacuum flusher. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 additives, n—various materials that are used in rela- tively small quantities to condition the pigment or vehicle. 3.1.2 break, n—the action that takes place when water is separated from the pigment in a presscake. 3.1.3 flushed color, n—a color base in paste form prepared by flushing. 3.1.4 flusher, n—a mixing device that has two sigma shaped agitator blades parallel to each other, turning in opposing directions at different speeds. 3.1.4.1 Discussion—The mixing action ofa flusher is that of kneading. 3.1.5 flushing, n—a method of transferring pigments from dispersions in water to dispersions in oil by the displacement of the water by oil. 3.1.5.1 Discussion—The resulting dispersions of flushing are known as flushed colors. 3.1.6 pigment, n—the fine solid particles of colorant used to give color to printing inks. 3.1.6.1 Discussion—The pigment particles are substantially insoluble in the vehicle and in water. 3.1.7 presscake, n—a mixture of pigment and water formed into a cake by passing through a filter press under pressure. 3.1.8 vacuum cycle, n—the time a flush is under vacuum to remove entrapped water. 3.1.9 vehicle, n—the liquid portion of an ink that holds and carries the pigment, provides workability and drying properties and binds the pigment to the substrate after the ink has dried.
5. Significance and Use
5.1 By following this practice it is possible to make repro- ducible flushes when using the same raw materials. Therefore, if someone wishes to evaluate the effect a different raw material has on a flush, it is possible to evaluate this effect by noting the change that occurs from a control flush to the experimental flush. This change can be, but is not limited to; such things as strength after vacuum, grind, grit, gloss etc. This practice can be used by ink companies, pigment companies or varnish companies. This practice is not meant to give absolute values but is meant to be used as a relative practice in which a control flush is made using a standard formula and the experimental flush is compared to the control flush. This practice is not meant to determine the absolute performance of a formula in production. Again it can be used to give a relative idea of how a formula will perform in production when a correlation has been established between laboratory flushing and production flushing.
8. Procedure
8.1 Fig. 1 illustrates a typical formula for a 1-L laboratory flusher. N OTE 2—It is common practice for formulas to be based on the amount of pigment calculated on a dry basis and not on the weight of presscake, since the amount of water in the presscake will vary from batch to batch. For example, a presscake can be referred to as 25 % dry or 25 % solids. This means that for every 100 kg of presscake there are 25 kg of pigment and 75 kg of water. Usually the entire quantity of presscake to be flushed will not fit in the flusher at one time. If this is the case, it is necessary to flush the required amount of pigment in a succession of breaks (see Fig. 1). N OTE 3—Many formulas call for two or more kinds of oil or varnish or resin solution etc. Directions are usually very specific as to how much should be used, when the various items should be added, and the order in which they are added. It is normal practice to add these items in the same order as shown on the formula. The vehicle having the best pigment wetting property is usually added first. In some formulas, however, judgment is left to the operator, as predictions cannot be made. N OTE 4—Flushing aids are very effective and should be used with care and good judgment. 8.2 First Break: 8.2.1 Add prescribed quantity of presscake to the flusher. 8.2.1.1 The presscake should be analyzed for dry weight or solids according to Test Methods D280. 8.2.1.2 All presscake should be weighed before it is charged to the flusher. 8.2.2 Agitate for 2 to 5 min. If using a multispeed flusher, agitate at low speed for 1 to 2 min then at high speed for 2 to 5 min. 8.2.3 Add flushing additive(s) if required. 8.2.4 Add vehicle in small quantities until break occurs.
