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VESTANAT IPDI is a commercial form of isophorone diisocyanate, a monomeric cycloaliphatic diisocyanate supplied as a low-viscosity liquid containing stereoisomers.
Its principal applications include polyurethane resin synthesis, waterborne polyurethane dispersions, urethane acrylates, adhesive prepolymers, and the manufacture of coating crosslinkers.
Its asymmetric molecular structure and differently reactive isocyanate groups enable controlled polymer synthesis, while its nonaromatic backbone contributes to resistance to yellowing in appropriately formulated polyurethanes.
CAS Number: 4098-71-9
EC Number: 223-861-6
Molecular Formula: C12H18N2O2
Molecular Weight: 222.28 g/mol
Synonyms: Isophorone diisocyanate, IPDI, Isophorone diamine diisocyanate, 5-Isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, 1-Isocyanato-3-(isocyanatomethyl)-3,5,5-trimethylcyclohexane, 1-Isocyanato-5-(isocyanatomethyl)-3,3,5-trimethylcyclohexane, 3-(Isocyanatomethyl)-3,5,5-trimethylcyclohexyl isocyanate, 3,3,5-Trimethyl-5-(isocyanatomethyl)cyclohexyl isocyanate, Isocyanic acid methylene(3,5,5-trimethyl-3,1-cyclohexylene) ester, 5-Isocyanato-1-Isocyanatomethyl-1,3,3-Trimethylcyclohexane, 3-Isocyanatomethyl-3,5,5-Trimethylcyclohexyl Isocyanate, 3-(Isocyanatomethyl)-3,5,5-Trimethylcyclohexyl Isocyanate, 3,3,5-Trimethyl-5-(Isocyanatomethyl)Cyclohexyl Isocyanate, Cyclohexane 5-Isocyanato-1-(Isocyanatomethyl)-1,3,3-Trimethyl, Isocyanic Acid Methylene(3,5,5-Trimethyl-3,1-Cyclohexylene) Ester, 3-Isocyanatomethyl-3,5,5-Trimethylcyclohexane Isocyanate, Isophorone-Based Diisocyanate, Cycloaliphatic Isophorone Diisocyanate, Cycloaliphatic Diisocyanate IPDI, Monomeric Isophorone Diisocyanate, IPDI Monomer, Isophorone Diisocyanate Monomer, Liquid Isophorone Diisocyanate, CAS 4098-71-9, CAS No. 4098-71-9, EC 223-861-6, EC No. 223-861-6, EINECS 223-861-6, UNII 43B0856528, UNII-43B0856528, PubChem CID 169132, ChemSpider 147926, ChEBI 53214, CHEBI:53214, DTXSID0023826, MDL MFCD00064956, MFCD00064956, BRN 2726467, CCRIS 6252, SCHEMBL15846, CHEMBL1509442, SCHEMBL27259114, SCHEMBL28693509, AKOS000120330
APPLICATIONS
Controlled polyurethane prepolymer synthesis
VESTANAT IPDI reacts with hydroxyl-functional materials to produce urethane-linked intermediates with structures determined by reactant functionality, stoichiometry, and reaction conditions.
An excess of isocyanate functionality produces prepolymers retaining reactive NCO end groups, whereas subsequent reaction with suitable chain extenders increases molecular weight.
This staged approach allows resin manufacturers to separate initial backbone construction from later chain extension or network formation.
VESTANAT IPDI offers a means of influencing prepolymer architecture because its two NCO groups occupy chemically different environments.
Catalyst selection changes their relative reaction rates and can influence the balance between initial polyol functionalization and further chain extension.
Controlling these competing reactions matters when the intended intermediate requires a particular viscosity, molecular-weight distribution, or concentration of unreacted monomer.
Waterborne polyurethane dispersions
VESTANAT IPDI supplies the diisocyanate component in polyurethane dispersions prepared from polyols and hydrophilic building blocks.
In an established anionic route, dimethylolpropionic acid introduces pendant carboxylic acid groups into an isocyanate-terminated prepolymer.
Neutralization converts these groups into ionic centers that facilitate dispersion of the developing polymer in water.
VESTANAT IPDI-derived prepolymers can undergo chain extension with suitable diamines, producing polyurethane-urea structures.
The sequence of neutralization, dispersion, and chain extension affects how the polymer develops and how its particles become stabilized.
These dispersions therefore require coordinated control of chemistry and mixing rather than simple addition of the neat monomer to water. ScienceDirect
VESTANAT IPDI-based dispersions can incorporate polyester or polyether soft segments to adjust the properties of the resulting films.
The identity and molecular weight of the polyol influence flexibility, tensile behavior, and interactions between soft and hard regions of the polymer.
Consequently, changing the soft segment can alter coating behavior even when the diisocyanate component remains unchanged.
Radiation-curable urethane acrylates
VESTANAT IPDI reacts with hydroxyl-functional acrylate materials to form oligomers containing both urethane linkages and polymerizable acrylate groups.
The urethane-forming reaction constructs the oligomer, while subsequent radiation curing polymerizes its unsaturated groups.
These are separate chemical stages, and the neat diisocyanate itself is not a complete ultraviolet-curable coating.
VESTANAT IPDI-based oligomers can incorporate hydroxyl-functional acrylates containing polyether or polyester segments.
Changing these segments modifies the spacing between reactive groups and the flexibility of the oligomer backbone.
This molecular design offers a route to balancing network formation with the mechanical behavior required of the cured film. journal.hep.com.cn
VESTANAT IPDI also participates in the synthesis of urethane methacrylate intermediates through reaction with hydroxyl-functional methacrylates.
Research formulations combining poly(propylene glycol), the diisocyanate, and hydroxypropyl methacrylate demonstrate how different intermediate structures can coexist within an oligomer mixture.
The composition of that mixture influences the properties of the subsequently cured polymer network.
Waterborne radiation-curable resins
VESTANAT IPDI can contribute to resins combining water dispersibility with radiation-reactive functionality.
An established synthesis approach combines the diisocyanate with a polyether polyol, an internal hydrophilic component, and a hydroxyl-functional methacrylate.
The resulting architecture places dispersing groups and polymerizable unsaturation within the same resin system.
Two-component coating crosslinkers
VESTANAT IPDI serves as a starting material for higher-functionality adducts and isocyanurate derivatives intended for polyurethane coatings.
These derivatives react with hydroxyl-functional binders to form crosslinked films, with automotive and transportation coatings among the established application areas.
Their functionality, viscosity, and monomer content differ from those of the starting diisocyanate.
VESTANAT IPDI-derived trimers can crosslink acrylic polyols containing multiple hydroxyl groups.
The balance between available NCO and OH groups affects network formation, while the hydroxyl content of the acrylic binder changes the potential density of urethane connections.
A coating formulation therefore requires consideration of both components rather than selection of the diisocyanate-derived hardener alone.
Blocked crosslinkers and heat-cured coatings
VESTANAT IPDI provides a precursor for blocked polyisocyanate crosslinkers in polyurethane powder coatings and heat-cured industrial paints.
Blocking temporarily suppresses the reactivity of isocyanate functionality, allowing the crosslinker to coexist with suitable reactive binders before baking.
The blocking chemistry determines the activation conditions, so the monomer has no universal deblocking temperature.
Moisture-curing resins and adhesive intermediates
VESTANAT IPDI contributes to NCO-terminated prepolymers for moisture-curing resins and reactive adhesive systems.
Atmospheric moisture participates in subsequent reactions that consume remaining isocyanate groups and develop the polymer structure.
Waterborne adhesives and hot-melt adhesives are also established application areas, although their polymer architectures and setting mechanisms differ.
Urethane-modified alkyds and solventborne binders
VESTANAT IPDI reacts with suitable hydroxyl-containing alkyd intermediates to produce urethane-modified alkyd resins.
This modification changes resin structure and can contribute to hardness development and resistance to yellowing.
Other established applications include flexible solventborne polyurethane binders, cast resins, tooling systems, and reaction injection molding formulations.
Specialized paper-treatment research
VESTANAT IPDI’s underlying chemical, isophorone diisocyanate, has been investigated in waterborne polyurethane emulsions for paper sizing.
Published research describes emulsions synthesized with polycaprolactone diol, dimethylolpropionic acid, and an ethylenediamine chain extender.
This application concerns a synthesized polymer emulsion rather than direct treatment of paper with the neat diisocyanate.
DESCRIPTION
Chemical identity and molecular structure
VESTANAT IPDI contains monomeric isophorone diisocyanate rather than a polyurethane resin or a preformed polyisocyanate oligomer.
The molecule has a substituted cyclohexane backbone bearing three methyl groups and two isocyanate functionalities.
One NCO group is attached directly to the ring, while the other is attached through a methylene group.
VESTANAT IPDI belongs to the cycloaliphatic diisocyanate class because its carbon framework contains a saturated ring.
Its molecular formula describes the diisocyanate molecule even though the commercial substance contains stereoisomers.
The stereoisomer mixture does not require the variable molecular formula or molecular weight appropriate to a polymer.
Unequal reactive sites
VESTANAT IPDI has a primary isocyanate site on its isocyanatomethyl substituent and a secondary site attached to the ring carbon.
These descriptions identify the carbon environments associated with the functional groups and do not establish a fixed order of reaction.
Experimental investigations show that relative reactivity depends on the catalyst and reaction conditions.
VESTANAT IPDI can exhibit greater reactivity at its secondary NCO group under certain tin-catalyzed urethane reaction conditions.
Other catalyst systems can reduce the difference between the two sites.
Accordingly, assuming that the primary site always reacts first can lead to an incorrect interpretation of prepolymer formation. Wiley Online Library
VESTANAT IPDI’s selectivity also depends on temperature and the structure of the hydroxyl-containing reaction partner.
These variables influence how rapidly the first and second NCO groups participate in successive reactions.
They therefore affect the distribution of reaction products as well as the overall rate of conversion.
Polymer-building behavior
VESTANAT IPDI reacts with alcohol groups to form urethane linkages through an addition reaction.
With difunctional polyols, this chemistry can construct chains, while multifunctional reactants introduce opportunities for branching and crosslinking.
The resulting topology depends on the functionality and proportions of all participating reactants.
VESTANAT IPDI supplies a relatively rigid cycloaliphatic unit within polymers containing longer flexible polyol segments.
The resulting material can contain regions differing in mobility and intermolecular association.
Its mechanical behavior consequently reflects the complete polymer composition rather than the diisocyanate structure in isolation.
Water interaction and moisture sensitivity
VESTANAT IPDI is not an inert liquid that can be diluted safely with water.
Its isocyanate groups react with moisture, and the reaction sequence can produce carbon dioxide and urea-containing products.
This chemistry can change composition, generate solids, and create pressure when gas evolution occurs within confined equipment.
VESTANAT IPDI also reacts with other active-hydrogen compounds, including alcohols and amines.
Such reactions are desirable during controlled resin manufacture but constitute incompatibilities during storage and accidental mixing.
Moisture contamination is therefore both a product-quality issue and a potential process hazard.
Dispersion behavior and process sequence
VESTANAT IPDI does not acquire water dispersibility simply because it participates in waterborne polyurethane manufacture.
Dispersibility develops through hydrophilic components incorporated into the polymer and through the subsequent neutralization and dispersion operations.
The timing of internal-emulsifier addition can influence polymer structure and the properties of the resulting polyurethane-urea dispersion.
Physical form and exposure significance
VESTANAT IPDI is a low-viscosity liquid, which facilitates metering into controlled synthesis equipment.
Its low ambient vapor pressure does not eliminate inhalation risk, particularly when mist forms or the material is heated.
The substance presents serious inhalation and sensitization hazards, requiring exposure controls appropriate to reactive liquid diisocyanates.
PROPERTIES
Chemical identity: Isophorone diisocyanate
Chemical class: Cycloaliphatic diisocyanate
Commercial form: Monomeric liquid containing stereoisomers
Appearance: Clear, colorless to slightly yellow liquid
Odor: Weak characteristic odor
Molecular formula: C12H18N2O2
Molecular weight: 222.28 g/mol
Isocyanate functionality: Two NCO groups per molecule
Water behavior: Insoluble; reacts with water and moisture
pH: Not applicable to the neat reactive liquid
Principal exposure hazards: Acute inhalation toxicity, respiratory sensitization, skin sensitization, and skin, eye, and respiratory irritation
Purity: At least 99.5% by weight in the documented commercial specification
NCO content: 37.5–37.8% by weight
Density: 1.058 g/cm³ at 20 °C
Dynamic viscosity: 13–15 mPa·s at 23 °C
Color: APHA below 10
Refractive index: 1.483 at 25 °C
Vapor pressure: 6.35 × 10−4 hPa at 20 °C
Flash point: 151 °C, closed cup
Autoignition temperature: 430 °C
FIRST AID
Inhalation:
Move the affected person to fresh air without exposing rescuers.
Seek emergency medical assistance immediately.
If breathing stops, trained personnel should provide assisted ventilation using suitable protective equipment.
Skin contact:
Remove contaminated clothing immediately and wash the affected skin thoroughly with soap and water.
Obtain medical attention.
Eye contact:
Immediately irrigate the eyes with plenty of water for at least 15 minutes.
Remove contact lenses if easily possible and continue rinsing.
Obtain urgent medical assessment.
Ingestion:
Rinse the mouth and obtain immediate medical advice.
Do not induce vomiting.
Give nothing by mouth to an unconscious person.
Note to physicians:
Provide symptomatic and supportive treatment, with attention to respiratory effects and possible sensitization.
HANDLING AND STORAGE
Handling:
VESTANAT IPDI requires closed transfer where practicable, splash protection, and chemically resistant gloves selected for the actual exposure conditions.
Prevent contact with skin and eyes and avoid breathing vapor or mist.
Ventilation:
Provide local exhaust at transfer, sampling, and processing points.
Where exposure control is insufficient, select respiratory protection through a competent occupational risk assessment.
Storage:
Keep containers tightly closed in a dry, ventilated, restricted-access area.
Protect against water ingress and unintended contact with alcohols, amines, or other reactive materials.
Spill and leak procedures:
Isolate the area and prevent entry into drains.
Trained responders should collect liquid with an absorbent confirmed compatible with reactive isocyanates.
Avoid improvised neutralization and manage contaminated material through an approved hazardous-waste procedure.
Handling precautions:
Keep equipment dry and control aerosol generation.
Remove contaminated clothing and wash after handling.
Account for possible gas generation when managing moisture-contaminated material.
