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D608-05 – Standard Test Method Technical Guide
📜 Standard Scope and General Requirements
ASTM D608-05 (Reapproved 2019) defines the requirements for dibutyl phthalate (DBP) of 99% grade. This specification is essential for applications in paints, varnishes, lacquers, and plastics where DBP serves as a plasticizer and solvent. All specified limits require strict adherence to the rounding-off methods defined in Practice E29. The values stated in SI units are to be regarded as the standard, and detailed hazard information is available in the supplier’s Safety Data Sheet.
💡 Key Note on Color Determination: While Test Method D1209 is the traditional standard for the Pt-Co scale, instrumental determination via Test Method D5386 has shown no statistically significant difference and is an acceptable alternative for determining conformance.
⚙️ Required Properties and Testing Protocols
Dibutyl phthalate must meet strict chemical and physical property limits to ensure suitability as an industrial chemical intermediate. The water content limit of 0.2 % ensures the material is miscible without turbidity when mixed with 19 volumes of 99 % heptane at 20 °C per Test Method D1476.
| 🟦 Property | 📏 Specification Limit | 🔬 Test Method (ASTM) |
|---|---|---|
| Apparent Specific Gravity (20/20 °C) | 1.046 to 1.050 | D4052 |
| Apparent Specific Gravity (25/25 °C) | 1.043 to 1.047 | D4052 |
| Color, Pt-Co Scale, max | 20 | D1209 / D5386 |
| Odor | Nonresidual | D1296 |
| Water, max, weight % | 0.2 | D1364 |
| Acidity (free acid as phthalic acid), max, weight % | 0.01 (equiv. to 0.067 mg KOH/g) | D1613 |
| Ester Value, min, weight % | 99.0 | D1617 |
Note that the odor requirement is optional and can be specified by mutual agreement between the supplier and consumer. The acidity limit is expressed as free phthalic acid, which is equivalent to 0.067 mg of KOH per gram of sample.
⚠️ Conformance Caution: For determining conformance with this standard, observed or calculated values must be rounded off “to the nearest unit” in the last right-hand digit used in expressing the specification limit, strictly following the rounding-off method of ASTM Practice E29.
📦 Sampling, Packaging, and Certification
Sampling of dibutyl phthalate must be conducted in accordance with ASTM Practice E300, ensuring representative samples for quality control. The standard also references U.S. Federal Specification PPP-C-2020 for the packaging of liquid chemicals. Proper handling and storage are critical to maintain the purity and properties outlined in Section 3.
❓ Frequently Asked Questions
🔍 What is the minimum ester value required for dibutyl phthalate to meet this specification?
The minimum ester value required for 99% grade dibutyl phthalate is 99.0 weight percent, as determined by Test Method D1617.
💡 Which specific test method is used to determine the water content of DBP?
Water content is determined using Test Method D1364, the Karl Fischer Reagent Titration Method. The maximum allowable water content is 0.2 weight percent.
⚡ What are the apparent specific gravity limits for dibutyl phthalate?
At 20/20 °C, the apparent specific gravity must range between 1.046 and 1.050. Alternatively, at 25/25 °C, the range is 1.043 to 1.047, tested per D4052.
📌 How should dibutyl phthalate be sampled for conformance testing?
The material must be sampled in accordance with ASTM Practice E300, which covers the standard procedures for sampling industrial chemicals.