ASTM D4942-89(2006)
(Test Method)Standard Test Methods for Water Pickup of Lithographic Printing Inks and Vehicles in a Laboratory Mixer
Standard Test Methods for Water Pickup of Lithographic Printing Inks and Vehicles in a Laboratory Mixer
SIGNIFICANCE AND USE
The lithographic printing process requires that some dampening solution be emulsified into the ink. These test methods provide a rapid means for determining water pickup under laboratory conditions. Test results may be useful for specification acceptance between the supplier and the customer.
In order that results be comparable, the tests must be run at the same temperature and with the same type and quantity of liquid added prior to mixing.
The emulsions obtained in these test methods are of larger particle size than those typically produced in printing nips. Because of these and other variables in the printing process, water pickup results do not by themselves predict lithographic printing performance.
SCOPE
1.1 These test methods cover two procedures for determining the amount of water picked up by lithographic printing inks in a laboratory mixer.
1.2 Test Method A covers single-point water pickup; Test Method B covers the rate of water pickup. Both test methods are applicable to any printing ink and vehicle intended for the lithographic printing process.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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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Standards Content (Sample)
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Designation:D4942–89(Reapproved2006)
Standard Test Methods for
Water Pickup of Lithographic Printing Inks and Vehicles in a
Laboratory Mixer
This standard is issued under the fixed designation D4942; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 In order that results be comparable, the tests must be run
at the same temperature and with the same type and quantity of
1.1 These test methods cover two procedures for determin-
liquid added prior to mixing.
ingtheamountofwaterpickedupbylithographicprintinginks
3.3 The emulsions obtained in these test methods are of
in a laboratory mixer.
larger particle size than those typically produced in printing
1.2 Test Method A covers single-point water pickup; Test
nips. Because of these and other variables in the printing
Method B covers the rate of water pickup. Both test methods
process, water pickup results do not by themselves predict
are applicable to any printing ink and vehicle intended for the
lithographic printing performance.
lithographic printing process.
1.3 The values stated in SI units are to be regarded as
4. Apparatus
standard. No other units of measurement are included in this
4.1 Laboratory Mixer, such as a Duke Ink-Water Emulsi-
standard.
fication Tester equipped with a stainless steel specimen bowl
1.4 This standard does not purport to address all of the
83 mm wide and 88 mm high, mixer blades that rotate at 90
safety concerns, if any, associated with its use. It is the
r/min, and a timing device.
responsibility of the user of this standard to establish appro-
4.2 Balance, accurate to 0.1 g, 600-g capacity.
priate safety and health practices and determine the applica-
4.3 Palette knives, two.
bility of regulatory limitations prior to use.
4.4 Thermometer, quick response.
2. Summary of Test Methods 4.5 pH Meter (optional).
4.6 Conductivity Meter (optional).
2.1 Thesetestmethodsutilizealaboratorymixerforbeating
4.7 Graduated Cylinder, 50 or 100-mL.
water or other agreed upon fluid into the test ink.
2.2 For single-point water pickup (Test Method A), 50 mL
5. Reagents and Materials
of water is normally added to 50 g of ink and mixed in for 5
5.1 Water—Deionized or distilled water, preferably having
min. The water picked up is determined from volumetric
a pH of 5.0 to 7.0 (100 to 200 mL per sample); alternatively,
measurements of free water.
fountain solution or other aqueous medium as agreed upon
2.3 Forrateofwaterpickup(TestMethodB),waterisadded
between the supplier and the customer may be used.
to 50 g of ink in increments of 20 mL and mixed in for 1 min
5.2 Cleanup Materials—Naptha and rags or tissues.
or more over a cumulative time period totaling 10 min. The
water taken up by the ink after each mixing interval is
6. Test Specimen
determined gravimetrically.
6.1 A minimum of 100 g is sufficient for two determina-
3. Significance and Use tions. Before removing ink from the can, stir or otherwise
ensure that the ink specimen is representative. Close the can
3.1 The lithographic printing process requires that some
and replace sealing tape immediately after each ink removal.
dampening solution be emulsified into the ink. These test
methods provide a rapid means for determining water pickup
7. Conditioning
under laboratory conditions. Test results may be useful for
7.1 Condition the instrument, water, and ink samples in a
specification acceptance between the supplier and the cus-
constant temperature room or bath, preferably at 23 6 1°C.
tomer.
7.2 Prior to use, check the alignment of the mixer blades.
With the power switch of the mixer in the off position, set the
These test methods are under the jurisdiction of ASTM Committee D01 on
clean bowl into the turntable and engage the locking pin firmly
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.56 on Printing Inks.
Current edition approved Nov. 1, 2006. Published November 2006. Originally
approved in 1989. Last previous edition approved in 2001 as D4942 - 89 (2001). Available from Duke Custom Systems, 8371 Highway 49, Pleasant View, TN
DOI: 10.1520/D4942-89R06. 37146.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4942–89 (2006)
NOTE 3—A commonly used cycle is 1-min intervals (90 revolutions)
into the slot in the side of the turntable. Tilt the mixer head
times ten determinations. Intervals need not be uniform, for example, 1, 2,
back and insert the blades, marked left and right, into their
3, 5, and 10 min (90 times 3 plus 180 plus 450 revolutions).
respective holders. Lower the mixer head. If the blades hit the
9.2 Optional—Measure water properties in accordance with
side or bottom of the bowl, return the instrument to the
manufacturer for realignment. 8.2.
9.3 Weigh or tare the clean dry mixing bowl and blades on
8. Test Method A—Single Point Water Pickup (by
the balance. Add 50 6 0.1 g of ink to the center of the bowl.
Volumetry)
9.4 Lock the bowl on the platform of the mixer. With the
8.1 Program the counter of the mixer for 5 min mixing time mixer head raised, carefully insert the blades into their respec-
(450 revolutions). tive holders. If ink on one blade touches the upper parts of the
8.2 Optional—If the first run of the day, pour test water into
other blade or the side of the bowl, carefully remove the ink
a beaker. Measure pH, conductivity, and temperature at the with two palette knives and transfer to the bottom of the bowl.
beginning of testing.
Lower the mixer head.
8.3 Weigh or tare the clean dry mixing bowl.Add 50 6 0.1 9.5 Pour 100 mL of water (from 8.2) into a beaker. Meter
g of the ink to the center of the bowl. out 20 mL and add to the bowl.
8.4 Pour 50 mL of water (from 8.2) into a graduated 9.6 Press the counter reset button, making sure that the
cylinder. If the ink is expected to pick up more than 100 % desired number of revolutions is displayed on the face of the
water, use 100 mL of water. Adjust the volume to 60.5 mL. counter. Turn the mixer on. Examine the contents of the bowl
Add the entire contents to the bowl. as mixing progresses. If all liquid disappears into the ink, add
8.5 With the mixer head tilted back insert the clean blades, more as needed to maintain a layer of excess water on the
marked left and right, into their respective holders. Lock the surface of the ink.
bowl on the turntable. Lower the mixer head. Press the counter
NOTE 4—Few specimens will take up more than 20 mLof water within
reset button, making sure that 450 is displayed on the face of
a 1-min mixing interval. If a high-water pickup specimen is being run and
the counter.
the mixing interval is longer than 1 min, another 20 mL should be added
8.6 Turn the mixer on. Examine contents of the bowl as
prior to each subsequent minute of mixing time.
mixing progresses. If 50 mL of water had been added and all
9.7 When the mixer stops, turn the power switch off. Detach
of it disappears into the ink, stop, discard the ink in the bowl,
the mixing blades and add to the bowl.
clean up, and start over from 8.3, adding 100 mL of water in
9.8 Remove the bowl from the turntable and, holding the
8.4. The latter quantity must also be used for all other i
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