Polyurethane-39 is an inorganic chemical compound, a segmented block copolymer derived from urethane and synthesised from isocyanates.

The name describes the structure of the molecule:

• "Polyurethane" is a term that describes a class of polymers widely used in various applications due to their versatility and desirable properties such as durability, flexibility and abrasion resistance and temperature variations.
• "-39" is a reference to the specific type or grade of polyurethane, which can be characterized by such factors as the types of isocyanates and polyols used, their relative amounts, and the presence of any additives. . This is a designation used to differentiate different molecular structures or variants of the polymer. In cosmetic chemistry, these numbers can help formulators identify specific characteristics or behaviors of a given ingredient, particularly when a chemical family has multiple derivatives or forms.

Significant substances used in the production method:

PEG-140. hexamethylene diisocyanate, C12-14 Pareth-10, C16-18 Pareth-11, C18-20 Pareth-11.

Description of raw materials used in production and their functions:

• PEG-140. A polyol that provides hydroxyl terminal groups for the reaction with isocyanates.
• Hexamethylene diisocyanate. A reactant that forms the urethane linkage with the polyol.
• C12-14 Pareth-10, C16-18 Pareth-11, and C18-20 Pareth-11. These are ethoxylated fatty alcohols that act as structure modifiers or as co-polyols in the polymer.

Step-by-step summary of industrial chemical synthesis process:

• Preparation. PEG-140 and the ethoxylated fatty alcohols are introduced into a reactor and heated to a specified temperature.
• Addition. Hexamethylene diisocyanate is slowly added to the reactor while stirring.
• Reaction. The urethane linkage forms between the polyol and the isocyanate reactant.
• Purification. Any unreacted components are removed, and the polyurethane is purified.
• Finalization. The resulting polyurethane is cooled and prepared for end applications.

What it is used for and where

Cosmetics

Surfactant - Suspending agent. Cosmetic or pharmaceutical suspensions are known to be thermodynamically unstable and it is therefore essential to include in the formulation a suspending agent capable of dispersing any sedimented particulates and reducing the rate of sedimentation. The presence of this agent increases the consistency of the suspension medium and exerts a protective colloidal action with a surfactant action.

Viscosity control agent. It controls and adapts, Increasing or decreasing, viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

Hair conditioning agent. A large number of ingredients with specific purposes can co-exist in a hair shampoo: cleansers, conditioners, thickeners, mattifying agents, sequestering agents, fragrances, preservatives, special additives. However, the indispensable ingredients are the cleansers and conditioners as they are necessary and sufficient for hair cleansing and manageability. The others act as commercial and non-essential auxiliaries such as: appearance, fragrance, colouring, etc. Hair conditioning agents have the task of increasing shine, manageability and volume, and reducing static electricity, especially after treatments such as colouring, ironing, waving, drying and brushing. They are, in practice, dispersing agents that may contain cationic surfactants, thickeners, emollients, polymers. The typology of hair conditioners includes: intensive conditioners, instant conditioners, thickening conditioners, drying conditioners.

It appears as a white powder or colorless liquid.

Safety

Urethane (also called ethyl carbamate) is a by-product of fermentation and is considered a genotoxic agent.

Polyurethanes are rather complex, inert and biostable materials that are also used in biomedical applications. They are typically synthesised by the reaction of a glycol or polyol with polyisocyanate or diisocyanate. It is known that exposure to isocyanates can cause asthma, contact allergies, conjunctival and skin irritation. However, a study by the Cosmetic Ingredient Review Expert Panel in 2017 found that the rates of harmful residues are not significant for human health.