Meaning and Purpose
3.1 These test methods can be used to determine the various stages and rates of drying, curing and film formation of organic coatings to compare coating types, to assess the effect of compositional changes on drying times, or to assess drying/curing times on the shop floor or in the field. Low temperatures can significantly slow down the drying rate of coatings, so it is often possible to use low-temperature curing agents, catalysts, and/or accelerators to aid in drying and film formation at cooler temperatures. Method B aims to assess these components and/or determine the effect of lower temperatures on drying rates. Conversely, the drying/curing rate of some coatings is accelerated under high temperature/humidity conditions, while others may be adversely affected by elevated humidity. Method C was designed to evaluate the effect of high temperature and relative humidity conditions on drying, curing and film formation of paints and coatings. The terms dry or dry, cured or cured, and film forming are used interchangeably throughout the standard.

3.2 Test Methods A, B and C are limited to comparing paints/coatings applied to smooth, non-absorptive substrates and do not reflect the effect of paint carrier absorption into substrates.

ASTM D 1640-2022: Drying, Curing, and Film Formation of Organic Coatings at Room Temperature

Scope of
1.1 These test methods cover the various stages and rates of film formation during drying or curing of organic coatings under laboratory controlled air temperature (low, ambient and/or elevated) and/or humidity conditions. Procedures for assessing drying under prevailing conditions of workshop and field temperature and humidity are also described.

1.2 Values expressed in SI units or ink-pound units should be treated separately as standard values. The values specified in each system are not necessarily the same; Therefore, to ensure compliance with the standards, each system should be used independently of each other and the values of the two systems should not be combined.

ASTM D 1640-2022: Drying, Curing, and Film Formation of Organic Coatings at Room Temperature

1.3 This standard is not intended to address all safety issues, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health and environmental practices and to determine the applicability of regulatory restrictions prior to use.

1.4 This international Standard has been developed in accordance with the internationally recognized standardization principles established in the Decision on Principles for the Development of International Standards, Guidelines and Recommendations issued by the Committee on Technical Barriers to Trade of the World Trade Organization.