Significance and Use

Ethyl silicate zinc-rich primers cure by the reaction of the vehicle with moisture, thereby providing a binder. As relative humidity and temperature vary during the day, so does the rate of cure. A certain minimum degree of cure is necessary prior to topcoating. It has been shown that the degree of cure of ethyl silicate zinc-rich primers can be measured by the chemical changes occurring using diffuse reflectance infrared spectroscopy. This solvent rub test has been shown to correlate well with the infrared spectroscopic results of some two-component ethyl silicate inorganic zinc systems.

The cure rating required for the application of specific topcoats must be agreed upon before the practice is used.

1. Scope

1.1 This practice describes a solvent rub technique for assessing the MEK resistance of ethyl silicate (inorganic) zinc-rich primers. The MEK resistance of some two-component ethyl silicate zinc-rich primers has been shown to correlate well with the cure of the primer as determined by diffuse reflectance infrared spectroscopy. The technique can be used in the laboratory, field, or in the fabricating shop. Practice D5402 is the preferred method for organic coatings.

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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 6. Consult supplier's Material Safety Data Sheet(s) for specific hazard information relating to the solvent used.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

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

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

Keywords

curing characteristics; double rub method; drying or curing; ethyl silicate (inorganic) primer; methyl ethyl ketone; MEK (methyl ethyl ketone) resistance; primer; solvent rub method; visual examination; zinc-rich primer; Curing characteristics; Double rub method; Drying or curing; Ethyl silicate (inorganic) primer; Ketones; Methyl ethyl ketone (MEK); Primers; Solvent rub method; Zinc-rich primer; Visual examination--paints/related coatings/materials;

ICS Code

ICS Number Code 87.040 (Paints and varnishes)

DOI: 10.1520/D4752-10

ASTM International is a member of CrossRef.

ASTM D4752