Polyurethane-64 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.
- "-64" 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 (IDPI), polytetrahydrofurans (PTHFs), polybutylene glycols, polytetramethylene glycols, PTHFs, butylene glycol, 4,4'-methylenebis(cyclohexylamine), ethanol.
Description of the raw materials used in production and their functions:
- Isophorone Diisocyanate (IDPI). Diisocyanate used to react with polyols to form polyurethane. It imparts strength and stability to the polymer.
- Polytetrahydrofurans (PTHFs). Polyols used in the synthesis of polyurethane elastomers, providing flexible segments to the polymer.
- Polybutylene Glycols and Polytetramethylene Glycols. Polyols that provide flexible segments to the polyurethane, enhancing its toughness and flexibility.
- Butylene Glycol. Low molecular weight polyol that regulates viscosity and improves the workability of the polyurethane.
- 4,4'-Methylenebis(cyclohexylamine). Cross-linking agent used to form bonds between the polyurethane chains, enhancing its mechanical properties.
- Ethanol. Solvent that regulates the viscosity of the reaction mix and aids in the workability of the polyurethane.
Step-by-step industrial synthesis:
- Polytetrahydrofurans (PTHFs), Polybutylene Glycols, Polytetramethylene Glycols, and Butylene Glycol are mixed to prepare a polyol mixture.
- Isophorone Diisocyanate (IDPI) is added to the reaction mixture, initiating the formation of the polyurethane.
- 4,4'-Methylenebis(cyclohexylamine) is introduced into the mixture, acting as a cross-linking agent.
- Ethanol is added to regulate the viscosity of the mixture and facilitate the reaction.
- The mixture is allowed to react until the desired molecular weight and consistency of the polyurethane is achieved.
- The resulting polyurethane is then cured through a thermal process, stabilizing its structure.
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.
