Oversize particles in a printing ink may damage a printing plate, plug a cell, clog a nozzle and adversely affect the appearance of printed ink films. Fineness of grind measurements are useful for deciding when to stop the dispersion process and for determining if the test material meets specifications as agreed upon between the supplier and the customer.
1.1 This test method describes the procedure for determining the fineness of grind of printing inks using a NPIRI Grindometer. It evaluates the size of the largest particles in a finished dispersion but not average particle size or concentration of sizes.
1.2 This test method covers both manual and automatic drawdowns using an A1 scraper.
1.3 This test method is applicable to any dispersion that is fine enough to fall within the 0-25 m range of the specified grind gauge. With a minor variation in procedure, it is applicable to both paste (nonvolatile) and liquid (volatile) inks.
Note 18212;The 0-25 m gauge specified in this test method is similar in principle to the 0-100 m Hegman gauge described in Test Method D 1210 and the various gauges described in ISO 1524:2000. Sieve analysis for concentration of particles above 45 m is covered in Test Method D 2067.
1.4 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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