Active Standard ASTM D7835 / D7835M | Developed by Subcommittee: D01.53
Book of Standards Volume: 06.02
Significance and Use
5.1 Many coatings used in the coil coating and other industries achieve a degree of solvent resistance after they have experienced a bake condition characterized by exposure to elevated temperatures in an oven over time. Insufficient bake, or occasionally over bake, may affect the intended chemical bonds or physical curing of the film and result in reduced solvent resistance.
5.2 The mechanical rubbing machine provides consistent stroke length, rate, pressure, and contact area that are not subject to variables such as human fatigue (see Practice D5402).
5.3 Factors other than bake can influence degree of solvent resistance of a coated surface. Paint film chemistry and composition, surface preparation, oven dwell time, oven air velocity, ambient oven temperature, oven profiling, film thickness, etc., all are influential. The test solvent used in the rub machine has a significant effect on the number of double rubs measured. Common solvents used for these tests include Methyl Ethyl Ketone (MEK), Methyl Isobutyl Ketone (MIBK), and Isopropyl Alcohol to name a few. The specific solvent to be used and the umber of double rubs to be achieved should be agreed upon between manufacturer and user for any given coating system, thickness, and application.
1.1 This test method covers a mechanical rub method for assessing the solvent resistance of an organic coating that chemically and/or physically changes during the curing process. This technique can be used in the laboratory, in the field, or in the fabricating shop.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D740 Specification for Methyl Ethyl Ketone
D4138 Practices for Measurement of Dry Film Thickness of Protective Coating Systems by Destructive, Cross-Sectioning Means
D5402 Practice for Assessing the Solvent Resistance of Organic Coatings Using Solvent Rubs
D5796 Test Method for Measurement of Dry Film Thickness of Thin-Film Coil-Coated Systems by Destructive Means Using a Boring Device
D6132 Test Method for Nondestructive Measurement of Dry Film Thickness of Applied Organic Coatings Using an Ultrasonic Gage
D7091 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals
ICS Number Code 25.220.60 (Organic coatings)
UNSPSC Code 23153800(Coating systems)