Polyurethane-25 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.
- "-25" 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:
dihydroxypolyoxobutylene (degree of polymerization 12-30), dimethylol propionic acid, meta-tetramethylenexylenediisocyanate, isophoronediisocyanate, trimethoylpropane, triethylamine, C1-8 alkyl diamine.
Description of raw materials used in production and their functions.
- Dihydroxypolyoxobutylene. Acts as the main hydroxyl-terminated polymer forming the backbone of the polyurethane.
- Dimethylol Propionic Acid. Provides additional hydroxyl groups for reaction with isocyanate groups.
- Meta-tetramethylenexylenediisocyanate. A source of isocyanate groups for polyurethane formation.
- Isophorone Diisocyanate (IPDI). Provides additional isocyanate groups for reaction.
- Trimethoylpropane. Introduces hydroxyl groups into the polymer network.
- Triethylamine. Used to neutralize the dimethylol propionic acid.
- C1-8 Alkyl Diamines. Acts as a chain extender, reacting with the remaining isocyanate groups.
Step-by-step summary of industrial chemical synthesis process.
- Dihydroxypolyoxobutylene, dimethylol propionic acid, and trimethoylpropane are reacted with meta-tetramethylenexylenediisocyanate and isophoronediisocyanate to form an isocyanate-terminated polyurethane prepolymer.
- Dimethylol propionic acid is neutralized using triethylamine.
- The C1-8 alkyl diamines are then added as chain extenders, reacting with the isocyanate groups to form the final 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.
Waving and straightening agent for hair. It is an ingredient that enables straightening and/or waving by permanently changing the shape or configuration of the keratinous hair fibres.
Skin conditioning agent. It is the mainstay of topical skin treatment by restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants.
Skin conditioning agent - Occlusive. This ingredient has the task of modifying the condition of the skin when it is damaged or dry by reducing flaking and restoring elasticity. It has a strong lipophilic character and is identified as an occlusive ingredient; it is generally composed of oily and fatty materials that remain on the skin surface and reduce trans epidermal water loss.
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.
