Glycol Ethers, High-Purity Solvents

Dipropylene Glycol N-Butyl Ether (DPNB)

Dipropylene Glycol N-Butyl Ether (DPNB), identified by CAS number 29911-28-2, is a high-performance, slow-evaporating, hydrophobic glycol ether. As a member of the P-series glycol ether family, it is synthesized through the reaction of propylene oxide with n-butanol. DPNB is a clear, colorless liquid characterized by a mild, ether-like odor and a high boiling point. It represents an excellent balance between hydrophilic and lipophilic properties, making it an exceptionally versatile solvent.

In the chemical industry, DPNB is highly regarded for its superior solvency across a broad spectrum of resins, including acrylics, epoxies, alkyds, and polyesters. Its slow evaporation rate and high plasticizing efficiency make it an ideal coalescent for water-borne coatings, where it assists in film formation and surface leveling. Furthermore, DPNB is favored for its favorable toxicological profile and high flash point, offering a safer alternative to many volatile organic compounds (VOCs) and traditional E-series solvents.

Attributes

Key Features and Benefits

Superior Coalescing Efficiency: Significantly reduces the minimum film-forming temperature (MFFT) in latex systems, ensuring a smooth, continuous, and durable film.
High Solvency Power: Effectively dissolves a wide range of organic resins and greasy soils, enhancing the performance of both coatings and cleaning agents.
Slow Evaporation Rate: Provides extended “open time,” which improves flow and leveling in paints and prevents surface defects such as “orange peel” or pinholing.
High Coupling Ability: Acts as an efficient intermediate to bridge oil-soluble and water-soluble components in complex chemical formulations.
Safety and Environmental Profile: Features low acute toxicity and high biodegradability; it is not classified as a hazardous air pollutant (HAP).
Hydrophobic Nature: Offers excellent water-resistance properties in dried coating films compared to more hydrophilic glycol ethers.

Specifications

Technical Highlights

Molecular Formula: C₁₀H₂₂O₃
Molecular Weight: 190.28 g/mol
Boiling Point: 230°C (446°F) at 760 mmHg.
Flash Point: 100°C (212°F) (Setaflash Closed Cup), offering low flammability risk during industrial handling.
Evaporation Rate: 0.006 (Relative to n-Butyl Acetate = 1), categorized as a very slow evaporator.
Vapor Pressure: 0.04 mmHg at 20°C, contributing to low VOC emissions in various applications.
Solubility: Partially soluble in water (5.0 g/100g at 25°C); highly miscible with most organic solvents.
Specific Gravity: 0.911 at 25°C.
Surface Tension: 28.4 dynes/cm at 25°C, facilitating excellent substrate wetting.