Polyurethane-49 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.
• "-49" 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:

poly(1,4-butanediol), 1,3-bis(isocyanatomethyl)benzene, ethoxylated 4,4'-isopropylidenediphenol, 4-hydroxybutyl acrylate.

Description of raw materials used in production and their functions:

• poly(1,4-butanediol). A polyol that provides hydroxyl terminal groups for reaction with diisocyanates.
• 1,3-bis(isocyanatomethyl)benzene. A diisocyanate used to form the urethane linkage with the polyols.
• ethoxylated 4,4'-isopropylidenediphenol (Bisphenol A ethoxylate). Acts as a chain extender and also as a modifier of polymer properties.
• 4-hydroxybutyl acrylate. An acrylate monomer that contributes to the properties of polyurethane and provides sites for further chemical reactions.

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

• Preparation. poly(1,4-butanediol), ethoxylated 4,4'-isopropylidenediphenol, and 4-hydroxybutyl acrylate are introduced into a reactor and heated to a specified temperature.
• Addition. 1,3-bis(isocyanatomethyl)benzene is slowly added to the reactor while stirring.
• Reaction. The urethane linkage forms between the polyols and the diisocyanate.
• Purification. Any unreacted components are removed, and the polyurethane is purified.
• Finalization. The resulting polyurethane is cooled and prepared for end applications.

What it is used for and where

Cosmetics

Nail Conditioning agent. It is an agent that creates protection against harmful or chemical substances by strengthening the nail structure against external elements and can repair any chipping, cracking or brittle nails. It helps keep the nail's outer layer and keratin protein in good condition. It can also prevent cracking and peeling of the nail.

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.