Polypropylene glycol (40) butyl ether is a synthetic, non-ionic surfactant and solvent built on a foundation of propylene oxide units capped at one end with a butyl group. With its unique chemistry, this compound shows up in laboratories, manufacturing facilities, and a handful of specialized consumer products. This glycol ether doesn’t float around as a common household word, yet in the world of raw materials, it stands as a workhorse, known for reliably bridging the gap between water and oil in chemical processing. In daily work, anyone who’s spent time in coatings, inks, or cleaning solutions will recognize this chemical’s signature: smooth wetting, extended solubility, more control over viscosity, and, sometimes, a challenge in handling its hazards.
Polypropylene glycol (40) butyl ether carries the molecular framework C3H8O repeating subunits, terminated by a butyl group, with the “40” indicating the average number of propylene glycol units. Its chemical formula is typically written as C3O(C3H6O)nC4H9, where n hovers around 40. This structure brings density and bulk to the molecule, which adds up to a liquid at room temperature—usually clear to pale yellow—with a reliable density sitting in the range of 1.01–1.05 g/cm³. Polymerization level directly impacts viscosity and solubility, and the butyl end grants solubility in organic phases. A worker who’s poured this from a drum can tell right away: it’s neither a powder, flake, nor crystal, but a slightly viscous, slick liquid that smells faintly chemical, never masking its laboratory roots.
This glycol ether arrives as a liquid, offering an agreeable compromise between volatility and viscosity. Density remains steady near 1.03 g/cm³, and viscosity ranges widely, shaped by molecular weight, but a “40” grade delivers a syrupy flow perfectly manageable in bulk storage or pump handling. Its high molecular weight helps it resist quick evaporation, which suits slow-drying paints and coatings. Unlike lower-molecular-weight ethers, there’s little risk of flammability in a typical working environment. Solubility with water isn’t as strong as with straight polyether chains, but it still dissolves in a manner that makes for reliable blending with glycol-based or organic matrices. Whether measured by the gallon, liter, or kilogram, every batch calls for precision; casual work with this chemical leads to broken emulsions and unpredictable results in the end product. Packaging skips forms like flakes, solids, crystals, pearls, or powder; bulk liquid storage is the norm, with tanks, drums, and intermediate containers being industry mainstays.
The backbone of polypropylene glycol (40) butyl ether supports an entire segment of manufacturers searching for strong wetting, detergency, coupling, or low toxicity in cleaners and coatings. In the shop, this means chemists and operators reach for this glycol ether to gain control over viscosity in water-reducible resins, or boost solubility in stubborn ink formulations. Its structure — one foot in the ether world, the other planted in glycol territory — makes it valuable for dispersing hydrophobic substances in aqueous solutions. Sourcing starts with raw propylene oxide, building chain by chain in a tightly controlled reactor, then capping with the butyl group. Documentation and traceability matter. Suppliers who list HS Code 2909499090 make international shipping easier, but regulations keep shifting, and anybody accustomed to buying across borders or setting up a new contract knows paperwork for this class of glycol ether takes time and vigilance. For those wanting a shortcut, no such thing exists.
Polypropylene glycol (40) butyl ether rarely wins awards for being harmless, yet it’s more benign than plenty of alternatives. Short-term exposure may cause skin and eye irritation, especially with repeated, unprotected contact or splash scenarios. Anyone in the field knows the sting of diluted glycol ether on skin; gloves become not a suggestion but standard practice. Spills call for absorbent pads and containment, and as always, avoid letting this liquid escape into waterways, since its persistence in aquatic environments can disrupt microbial life and bioaccumulate if unchecked. Storage should be cool, away from strong acids, oxidizers, and direct sunlight. Proper ventilation, sealed storage, regular drum inspection, and up-to-date MSDS backup routine safety. Fire codes and local hazardous material regulations guide warehousing, but project managers and safety officers alike need regular reminders to train staff and check secondary containment systems.
Every step from formula to finished blend depends on a clear understanding of how polypropylene glycol (40) butyl ether interacts at the molecular level. The high molecular weight and butyl capping confer resistance to breakdown, extending service life in lubricants and reducing volatility in open-air applications. That’s why formulators don’t swap it out casually. Modifying even one end group or chain length changes viscosity, solubility, and performance. Factories depend on its consistent quality, and those who remember supply chain hiccups or off-spec shipments appreciate the value of verified, tested lots. Downstream, product developers can tweak coatings for better scratch resistance or longer drying times — all rooted in molecular structure. Safe use still boils down to respect for the raw material, diligent documentation, and steady investment in worker training and updated hazard protocols. Cutting corners here quickly turns a helpful chemical into a source of regulatory headaches, environmental risk, or worker injury.
Chemical producers, buyers, and regulators benefit by sharing clear data, safe handling directions, and honest communication on hazards. Manufacturers investing in closed systems, spill-prevention, and leak detection tighten control over exposure and environmental release. Scientists probing the limits of glycol ethers push for safer alternatives and ways to make production less resource-intensive and more sustainable. End users — whether technicians, engineers, or line operators — set the ultimate standard for safety: everyday routines that prevent careless mixing, spills, and exposure. Regular audits, accident reviews, updated MSDS folders, and practical spill response kits do more than comply with law; they help keep workers and communities safe.
Chemical Name: Polypropylene glycol (40) butyl ether
Chemical Formula: C3O(C3H6O)nC4H9 (n ≈ 40)
HS Code: 2909499090
Physical State: Clear to pale yellow liquid, density 1.01–1.05 g/cm³
Main Applications: Surfactant, solvent, wetting and dispersing agent, viscosity modifier
Packaging: Bulk liquid (drums, tanks); not available as powder, flakes, pearls, solid, or crystal
Key Safety Concerns: Skin/eye irritation, environmental hazard when released untreated, use with proper PPE
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