Polyurethane-50 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.
• "-50" 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)l, 1,3-bis(isocyanatomethyl)benzene, ethoxylated 4,4'-isopropylidenediphenol, 4-hydroxyethyl acrylate.

Description of raw materials used in production and their functions:

• poly(1,4-butanediol): This serves as the polyol component, contributing flexibility to the final polymer.
• 1,3-bis(isocyanatomethyl)benzene: This is the diisocyanate component, which reacts with polyols to form the urethane linkage.
• ethoxylated 4,4'-isopropylidenediphenol: A polyol with ethoxylated side chains. It imparts specific properties to the polyurethane, such as improved hydrophilicity.
• 4-hydroxyethyl acrylate: This monomer has dual functionality – a hydroxyl group for reaction with isocyanates and an acrylic group for potential UV curing or crosslinking.

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

• Preparation. The poly(1,4-butanediol) is introduced into a reactor and heated to a set temperature to ensure it is in a molten state, ready for the reaction.
• Addition. Ethoxylated 4,4'-isopropylidenediphenol and 4-hydroxyethyl acrylate are added to the reactor. The mixture is stirred to achieve a homogeneous blend.
• Reaction. 1,3-bis(isocyanatomethyl)benzene is slowly added to the reactor. The reaction between the polyol components and the diisocyanate forms the urethane linkages. This reaction is exothermic, so the temperature is carefully monitored and controlled.
• Curing. After achieving a complete reaction, the mixture is cooled. Depending on the desired final properties, further curing or crosslinking may be initiated, especially considering the acrylic groups present in 4-hydroxyethyl acrylate.
• Purification. Any unreacted components are removed, and the polyurethane is purified.
• Finalization. The resulting polyurethane is cooled and prepared for final applications, either as a solid or further processed into solutions or dispersions.

What it is used for and where

Cosmetics

Nail Conditionng 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.