Polyurethane-24 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.
• "-24" 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:

isophorone diisocyanate (IPDI), Poly(1,4-Butanediol)-30, 1,4-Butanediol, dimethylol butanoic acid, Aminpropyl Triethoxysilane, lauryl acrylate, isophorone diamine, Polyurethane-24.

Description of raw materials used in production and their functions.

• Isophorone Diisocyanate (IPDI). Provides isocyanate groups for polyurethane formation.
• Poly(1,4-butanediol)-30 Polyether. A hydroxyl-terminated polymer that serves as the main backbone of the polyurethane.
• 1,4-Butanediol. Offers hydroxyl groups to react with the isocyanate groups.
• Dimethylol Butanoic Acid. Provides additional hydroxyl groups for reaction.
• Aminopropyl Triethoxysilane. A silane coupling agent enhancing adhesion.
• Lauryl Acrylate. A comonomer introducing flexibility and toughness to the polyurethane.
• Isophorone Diamine (IPDA). Serves as a chain extender and reacts with the isocyanate groups.

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

• IPDI is initially reacted with the poly(1,4-butanediol)-30 and 1,4-butanediol to form an isocyanate-terminated polyurethane prepolymer.
• Dimethylol butanoic acid, aminopropyl triethoxysilane, and lauryl acrylate are subsequently introduced into the mixture.
• Isophorone diamine is then added as a chain extender, reacting with the isocyanate groups to form the final 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.

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.