ASTM Committee D01 reports of January 2007 subcommittee activities

JCT CoatingsTech, June, 2007

The group on Hardness, Mar and Abrasion Resistance, P. Guevin, Chair, heard a presentation on the round-robin study on samples tested in accordance with D 4060, "Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser," (Research Report D01-1135). A copy of proposed technical and editorial changes to Test Method D 4060 also was handed out. These changes along with the revised precision statement and revised Table I will be sent out for ballot. The chair noted that editorial revisions were made to D 968-05, "Test Method for Abrasion Resistance of Organic Coatings by Falling Abrasives." He also advised the group that WK13558 had been issued for the revision of D 2134, "Test Method for Determining the Hardness of Organic Coatings with the Sward-Type Rocker."

The Contact Angle Measurements group (C. Schoff, Chair) discussed two documents on surface wettability by measuring advancing contact angles (WK 11928) and the measurement of solid surface tension via contact angles (WK 11929). Because of concerns about the ability to develop precision statements and earlier suggestions that these documents should be practices, both documents were presented as practices rather than test methods. However, they both need additional work.

D01.24, Physical Properties of Liquid Paints and Paint Materials

C. Schoff, Chair

The group on Dispersion Phenomena discussed the two oil absorption methods, D281, "Oil Absorption of Pigments by Spatula Rubout," and D1483, "Oil Absorption of Pigments by Gardner-Coleman Method." These are old methods and there was a question as to whether they still were used, but the answer seems to be yes. They will be reviewed for possible revisions. It was suggested that D281 might be revised to include a fixed rub-out time limit in minutes that the user would establish for his or her specific product or product line. D1483 probably will be balloted for reapproval as-is.

The Viscosity Methods group continued the discussion on two new draft standards. One is a standard practice for rheological characterization of architectural coatings using three common bench viscometers (WK12492) that should be useful to the industry. The other is a cone/plate viscometer measurement at 500 se[c.sup.-1] (WK13901) that is of interest to auto makers and their paint suppliers as an alternative to efflux cups for measurements on topcoats. A number of changes were made in the methods so that they could be put forward for subcommittee ballot.

The Electrical Resistivity group discussed the need for revision for D5682, "Electrical Resistivity of Liquid Paints and Related Materials." The method was reapproved in 2002, but is out-of-date with respect to many ASTM rules and guidelines and needs to be revised. A somewhat revised draft was handed out and will be balloted. The group on New Ideas and Miscellaneous Methods discussed a number of possible new standards, including a method to measure yield stress, a guide for measuring viscosity as a function of temperature, a method for measurement of heat age stability and possible application of the ink resin viscoelasticity method to paints.