Polyurethane-73 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.
- "-73" 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:
hydrogenated polybutadiene diol, 1,6-hexamethylene diisocyanate (HDI), Hydrogenated Dilinoleyl Alcohol, Stearyl Alcohol.
Description of the raw materials used in production and their functions.
- Hydrogenated polybutadiene diol. An elastomer-based diol used as the main component in the polyol system, imparting elasticity and toughness to the polyurethane.
- 1,6-Hexamethylene diisocyanate (HDI). An aliphatic diisocyanate used as a cross-linking agent to form the main structure of the polyurethane through isocyanate reactions.
- Hydrogenated Dilinoleyl Alcohol. A polyunsaturated alcohol, hydrogenated for improved stability, used to impart flexible properties and modify the morphology of the polyurethane.
- Stearyl Alcohol. A long-chain fatty alcohol that serves as a plasticizing agent and to regulate the physical properties of the polyurethane.
Step-by-step industrial synthesis.
- Preparation. Hydrogenated polybutadiene diol and Hydrogenated Dilinoleyl Alcohol are mixed to form a polyol base.
- Reaction. 1,6-Hexamethylene diisocyanate is added, initiating the formation of polyurethane.
- Modification. Stearyl Alcohol is introduced to modulate the flexibility and physical properties of the polymer.
- Curing. The mixture is left to cure to ensure complete reaction and obtain the desired polyurethane.
What it is used for and where
Cosmetics
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.
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.
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.
