Polyurethane-68 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.
- "-68" 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:
hexamethylene diisocyanate (HDI isocyanurate trimer), PPG-30 Butyl Ether, 2-pyridylethanol,1-isobutanol.
Description of raw materials used in production with their functions.
- Hexamethylene Diisocyanate (HDI Isocyanurate Trimer). A diisocyanate used as a cross-linking agent to form urethane bonds, imparting strength and stability to the polyurethane.
- PPG-30 Butyl Ether. A propylene glycol polyether providing flexibility and contributing to the mechanical properties of the polyurethane.
- 2-Pyridylethanol. An alcohol used to modulate the reactivity of the system and improve reaction termination.
- 1-Isobutanol. A solvent and rheology modifier influencing the system's viscosity during polymer formation.
Step-by-step summary of industrial chemical synthesis process.
- PPG-30 Butyl Ether is reacted with HDI Isocyanurate Trimer to form a prepolymer.
- 2-Pyridylethanol is then introduced into the mixture to control reactivity.
- 1-Isobutanol is added as a solvent and to adjust the viscosity of the system.
- The reaction continues until the desired polyurethane forms.
What it is used for and where
Cosmetics
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.
CAS: 157420-46-7
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.
Polyurethane-68 
