Polyurethane-71 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.
- "-71" 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, Adipic Acid, isophthalic acid, isophorone diisocyanate, dimethylolpropionic acid, Triethylamine, Isopropanolamine, ethylene diamine.
Description of the raw materials used in production and their functions.
- Hexanediol. A polyol that provides flexible segments to the polyurethane, enhancing its toughness and flexibility.
- Adipic Acid and Isophthalic Acid. Acids used in the production of polyester urethane. They contribute to the strength and mechanical properties of the polyurethane.
- Isophorone Diisocyanate. Diisocyanate used to react with polyols to form polyurethane. It provides strength and stability to the polymer.
- Dimethylolpropionic Acid (DMPA). A carboxylic acid that provides hydrophilic functional groups to the polyurethane, enhancing its water solubility properties.
- Triethylamine and Isopropanolamine. Neutralizing agents used to adjust the pH of the system and promote the water solubility of the polyurethane.
- Ethylene Diamine. A crosslinking agent used to enhance the mechanical properties of the polyurethane.
Step-by-step industrial synthesis.
- Preparation. Hexanediol is mixed with Adipic Acid and Isophthalic Acid to form a polyester prepolymer.
- Reaction. Isophorone Diisocyanate is added to the mixture, initiating the polyurethane-forming reaction.
- Modification. Dimethylolpropionic Acid, followed by Triethylamine and Isopropanolamine is introduced to neutralize and adjust the properties of the polyurethane.
- Crosslinking. Ethylene Diamine is added to further crosslink the polyurethane and enhance its mechanical properties.
- Curing. The mixture is left to cure to ensure a complete reaction and obtain the desired polyurethane.
What it is used for and where
Cosmetics
Binder agent. Ingredient that is used in cosmetic, food and pharmaceutical products as an anti-caking agent with the function of making the product in which it is incorporated silky, compact and homogenous. The binder, either natural such as mucilage, gums and starches or chemical, may be in the form of a powder or liquid.
Film-forming agent. It produces, upon application, a very thin continuous film with an optimal balance of cohesion, adhesion and stickiness on skin, hair or nails 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.
