Polyurethane-92 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.
- "-92" 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:
Hexanediol, Dimethyl Carbonate, Dimethylolbutyric Acid, 1,4-Butanediol, Isophorone Diisocyanate, Lysine, Sodium Carbonate.
Description of the raw materials used in production and their functions:
- Hexanediol. Used as a diol component in forming polyurethane. Provides the polymer with flexibility and resilience.
- Dimethyl Carbonate. A carbonating agent, can react with alcohols to form esters.
- Dimethylolbutyric Acid. Provides hydroxyl groups for the reaction with isocyanates.
- 1,4-Butanediol. Diol used to enhance the elasticity of polyurethane.
- Isophorone Diisocyanate. Diisocyanate used to react with polyols to form polyurethane.
- Lysine. Amino acid that can function as a catalyst or cross-linking component in polyurethane formation.
- Sodium Carbonate. Can be used as a catalyst or neutralizing agent in the reaction.
Step-by-step industrial synthesis:
- Hexanediol, Dimethylolbutyric Acid, and 1,4-Butanediol are mixed in a reactor to prepare the polyol base.
- Dimethyl Carbonate is added to react with some of the diol components.
- Isophorone Diisocyanate is subsequently added to the polyol mixture, initiating the formation of the polyurethane.
- Lysine is introduced as a cross-linking component or catalyst.
- Sodium Carbonate is added to neutralize any residual acidity or as an additional catalyst.
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.
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.
