Non-Volatile Matter (NVM) Analysis: Methods, Standards, and Applications
What Is Non-Volatile Matter?
Non-Volatile Matter (NVM) — also known as total solids, dry residue, solids content, or non-volatile content — is the mass fraction of a liquid material (coating, adhesive, ink, lubricant, or solution) that remains after all volatile components (solvents, water, volatile diluents) are evaporated under defined heating conditions. It is expressed as a percentage of the original sample mass:
NVM (%) = (Mass of residue / Initial sample mass) × 100
NVM is one of the most routinely measured properties of liquid materials in the coatings, adhesives, inks, and lubricants industries — providing a direct measure of the product’s active, functional content.
Why NVM Testing Is Important
Formulation Quality Control
NVM directly measures the concentration of film-forming polymers, pigments, fillers, and non-volatile additives in a coating or adhesive. Deviations from the specified NVM indicate dilution by excess solvent, raw material substitution, or measurement or blending errors during manufacturing.
Performance Prediction
Dry film thickness (DFT) after application is directly proportional to NVM — thinner wet film applications of the same product produce the same DFT because NVM determines how much solid residue remains. Coverage rate calculations per unit area require accurate NVM data. All of these directly affect the corrosion protection and durability performance of applied coatings.
VOC Content Calculation
NVM is required for VOC content calculation per EPA Method 24 and equivalent international regulations. VOC (g/L) = Density × (1 − NVM/100) × (1 − Water/100) — providing the regulatory compliance data needed for air quality permits.
Product Shelf Life Monitoring
Changes in NVM over time indicate solvent evaporation from inadequately sealed containers or polymerisation (premature crosslinking) in reactive systems. NVM monitoring is part of shelf life qualification testing for coatings and adhesives.
Test Methods for NVM
ASTM D2369 — NVM of Coatings
The primary ASTM method for NVM of coatings. A defined mass of liquid coating is spread on a foil dish, heated at 110°C ± 2°C for 60 minutes, cooled, and reweighed. NVM is calculated from the mass retained. The method is straightforward but requires consistent specimen preparation (uniform spreading to approximately 0.1 mm wet thickness) for reproducible results.
ISO 3251 — NVM of Paints, Varnishes, and Plastics Dispersions
ISO 3251 provides conditions equivalent to ASTM D2369 (typically 105°C–135°C for defined times, depending on material class), with specific provisions for different material types. Temperature and time are more explicitly defined by material category in ISO 3251.
ASTM D1259 — NVM of Cellulosic Solutions
For cellulosic lacquers and coatings containing nitrocellulose, ASTM D1259 uses a lower temperature (105°C) to avoid oxidative degradation of the cellulosic residue.
ASTM D1353 — NVM of Adhesives
Adhesive NVM is determined by spreading a defined mass on glass or aluminium foil and heating at 105°C for a defined time. For pressure-sensitive adhesives, conditions are adapted to avoid crosslinking or oxidation during evaporation.
NVM vs. Solid Content: Terminology Clarification
In some industries, “solid content” and “NVM” are used interchangeably. Technically, NVM includes all non-volatile materials — polymers, pigments, plasticisers, fillers — while “solid content” sometimes specifically refers to the film-forming polymer fraction only. The applicable standard defines which fraction is being measured.
Industrial Applications
In the automotive coatings industry, NVM monitoring ensures that primer, basecoat, and clearcoat formulations deliver specified DFT at the designed spray application parameters. In the adhesives industry, NVM determines the adhesive’s solids delivery rate — a critical factor for continuous bond-coating operations. In printing inks, NVM affects ink opacity, colour strength, and drying time.
Conclusion
Non-Volatile Matter (NVM) — the residual solid content remaining after the evaporation of volatile components — is a fundamental parameter for evaluating the formulation quality, performance, and regulatory compliance of coatings, adhesives, inks, and related materials. Measured using standards such as ASTM D2369 and ISO 3251, it provides direct insight into active material concentration, film thickness potential, and VOC calculations. Accurate determination of NVM is essential for ensuring product consistency, application performance, and shelf-life stability — making the testing methodology as important as the measured value itself.
Why Choose Infinita Lab for NVM Analysis?
Infinita Lab provides NVM testing per ASTM D2369, ISO 3251, ASTM D1353, and related standards for coatings, adhesives, inks, and resins through our nationwide accredited analytical testing laboratory network.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you.
Frequently Asked Questions (FAQs)
What temperature is used in ASTM D2369 for NVM testing of solventborne coatings? ASTM D2369 specifies 110°C ± 2°C for 60 minutes as the standard condition. For materials containing high-boiling solvents (>150°C boiling point), the 110°C condition may not completely remove all solvents, giving erroneously high NVM values — higher temperature or longer time may be required as agreed between customer and supplier.
How does NVM relate to the dry film thickness of an applied coating? DFT (µm) = WFT × NVM/100, where WFT is wet film thickness. Coatings with higher NVM produce thicker dry films at the same wet application thickness. NVM must be accurately known to specify the correct wet film application thickness to achieve a target DFT.
Can NVM testing detect if a coating has been excessively diluted? Yes. Reducing (thinning) a coating with additional solvent reduces the NVM proportionally. If a product specification requires NVM of 55 ± 2%, a diluted sample will show NVM below 53% — indicating unauthorised thinning beyond specification. NVM testing is therefore an effective incoming material QC tool for detecting diluted coatings.
Why is sample preparation (spreading method) important in ASTM D2369? The sample must be spread to a thin, uniform layer to ensure complete solvent evaporation during the test period. A pooled or thick specimen may have incompletely evaporated solvent, giving erroneously high NVM. Consistent specimen preparation (typically circular spreading on aluminium foil using a wire coater or spreading stick) is essential for reproducible results.
Is NVM the same as the reactive solids content in a two-component coating? Not exactly. NVM measures the total non-volatile residue after curing. In two-component (2K) coatings, both components contribute non-volatile reactive species (epoxy resin + amine hardener, for example). The measured NVM of the cured film may differ slightly from the calculated value based on components alone due to volatile reaction byproducts or incomplete cure under test conditions.
