Overview
EN ISO 277:2010 (ISO 277:2002) - "Binders for paints and varnishes - Raw tung oil - Requirements and methods of test" defines quality requirements and standardized test methods for two types of raw tung oil used as binders for paints and varnishes. The standard covers Type F (Aleurites fordii) and Type M (Aleurites montana) raw tung oils and is not intended for oils that have partially or wholly solidified by polymerization.
Key topics and technical requirements
- Scope and types: Specifies two types (Type F and Type M) of raw tung oil and their intended use in coatings.
- Physical and chemical limits:
- Density (20 °C / 23 °C): defined ranges for each type (e.g., Type F ~0.935–0.940 g/ml at 20 °C).
- Refractive index (20 °C / 23 °C): specified ranges (e.g., Type F ~1.517–1.521 at 20 °C).
- Colour: measured by the Gardner scale (maximum Gardner 8).
- Acid number and saponification number (saponification ~189–195 mg KOH/g).
- Volatile (water) content: maximum 0.5% by mass.
- Iodine number: specified for Type M (minimum ≈205 g I2/100 g); calculated from fatty-acid composition.
- Gelation time: maximum limits (Type F max 15 min; Type M max 22 min).
- Sediment and turbidity: no insoluble sediment after 24 h; oil must be clear.
- Insoluble-bromide test: negative result required.
- Fatty-acid profile: Typical gas-chromatographic composition is given (notably α-eleostearic acid 64–80%, plus oleic, linoleic, palmitic, stearic).
- Test methods and sampling: Specifies sampling per ISO 15528 and references established test methods (e.g., ISO 2811-1 for density, ISO 5508/5509 for GC analysis of fatty acids). Detailed procedures such as the gelation-time test (heating block at 275–277 °C) are included.
Applications and users
- Who uses this standard:
- Paint and varnish manufacturers and formulators specifying raw tung oil as a binder.
- Raw material suppliers and quality control laboratories for batch acceptance testing.
- Procurement, regulatory and conformity assessment teams requiring objective acceptance criteria.
- Practical value:
- Ensures consistent performance and compatibility of tung oil in coatings (drying behavior, film formation).
- Supports supplier specifications, incoming inspection, formulation decisions, and dispute resolution.
- Facilitates international trade by harmonizing test methods and limits.
Related standards
Relevant normative references include ISO 150 (linseed oil), ISO 2811-1 (density), ISO 4630 (Gardner colour), ISO 5508/5509 (fatty-acid analysis), ISO 10336 (water by Karl Fischer) and ISO 15528 (sampling).
Keywords: EN ISO 277:2010, ISO 277:2002, raw tung oil, binders for paints and varnishes, gelation time, fatty-acid composition, test methods, quality control.