Polyurethane-16 is an inorganic chemical compound, a segmented block copolymer derived from urethane and synthesised from isocyanates. Significant substances used in the production method: hexamethylene diisocyanate, polycaprolactonetriol.
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.
- "-16" 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.
Description of raw materials used in production and their functions.
- Hexamethylene Diisocyanate. Provides isocyanate groups that react with hydroxyl groups to form polyurethane.
- Polycaprolactonetriol terminated with 3 hydroxyl groups. A tri-functional polyol that serves as the main building block and provides the terminal hydroxyl groups for reaction with the diisocyanate.
Step-by-step summary of industrial chemical synthesis process.
- Two stoichiometric equivalents of hexamethylene diisocyanate are mixed with one stoichiometric equivalent of polycaprolactonetriol.
- The mixture reacts through an addition polymerization, where the isocyanate groups react with the hydroxyl groups.
- Polyurethane-16 is formed as a cross-linked polymer.
What it is used for and where
Cosmetics
Anticaking agent. This compound facilitates free flow and prevents aggregation or clumping of substances in a formulation by reducing the tendency of certain particles to stick together.
Film-forming agent. It produces a continuous ultra-thin film with an optimal balance of cohesion, adhesion and stickiness on the skin or hair to counteract or limit damage from external phenomena such as chemicals, UV rays and pollution.
Emulsion stabiliser. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. as well as their shelf-life. It should be noted that in the structure-function relationship, the molar mass of the ingredient used plays an important role.
Slip modifier. It increases the spreadability of a product by helping other substances flow more smoothly and easily, without chemical reaction.
Surface modifier. Substance that has the property of preventing superficial defects in the epidermis by repelling oils and water and of giving the skin greater resistance against blemishes.
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.
