Polyurethane-46 is an inorganic chemical compound, a segmented block copolymer derived from urethane and synthesised from isocyanates.

Significant substances used in the production method:

isophorone diisocyanate (IPDI), poly(1,4-butanediol)-30, methoxy PEG-20, 2,2 dimethyol butoxy group, Methyl Diethanolamine.

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.
• "-46" 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.

Description of raw materials used in production and their functions.

• poly(1,4-butanediol)-30. A diolic component that reacts with isocyanate groups or other functional groups to form urethane linkages.
• methoxy PEG-20. Provides flexibility and enhancement of hydrophilic properties in the polyurethane.
• 2,2 dimethyol butoxy group. Provides additional hydroxyl groups for reaction and might contribute to the flexibility of the polymer.
• methyl diethanolamine. A neutralizing agent and potentially a chain extender.
• lauryl acrylate. Can act as a co-monomer for copolymerization or to enhance surface properties.
• aminopropyl triethoxysilane. A silane coupling agent that might enhance adhesion to various substrates.
• dimethylsulfate. An alkylating agent that might be used to modify specific functional groups.

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

• poly(1,4-butanediol)-30, methoxy PEG-20, and 2,2 dimethyol butoxy group are mixed and reacted with a potential isocyanate agent or other source of functional groups to form a polyurethane prepolymer.
• Coupling agents like aminopropyl triethoxysilane might be added to enhance adhesion or interface properties of the polymer.
• Lauryl acrylate might be introduced for copolymerization or to modulate the polymer's surface properties.
• Methyl diethanolamine and dimethylsulfate can be used at various stages for neutralization, chain extension, or other chemical modifications.

What it is used for and where

Cosmetics

It is a restricted ingredient as III/62  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: Trialkylamines, trialkanolamines and their salts

Hair conditioning agent. A large number of ingredients with specific purposes can co-exist in a hair shampoo: cleansers, conditioners, thickeners, mattifying agents, sequestering agents, fragrances, preservatives, special additives. However, the indispensable ingredients are the cleansers and conditioners as they are necessary and sufficient for hair cleansing and manageability. The others act as commercial and non-essential auxiliaries such as: appearance, fragrance, colouring, etc. Hair conditioning agents have the task of increasing shine, manageability and volume, and reducing static electricity, especially after treatments such as colouring, ironing, waving, drying and brushing. They are, in practice, dispersing agents that may contain cationic surfactants, thickeners, emollients, polymers. The typology of hair conditioners includes: intensive conditioners, instant conditioners, thickening conditioners, drying conditioners.

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.