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Isophorone Diisocyanate IPDI, also known as Isophorone Diisocyanate in Turkish, is a cycloaliphatic diisocyanate with the molecular formula C₁₂H₁₈N₂O₂. This raw material, which carries two reactive isocyanate groups per molecule, is an important chemical building block, especially used in the preparation of high-performance polyurethanes. For initial studies in polyurethane prepolymer development, monomeric IPDI can be evaluated at approximately 15–25% of the total formulation; 19% IPDI can be used as an example starting point. The exact utilization rate should be calculated based on the polyol's hydroxyl number, functionality, and targeted NCO/OH ratio.
Isophorone Diisocyanate IPDI stands out in applications where color change must be limited in polyurethanes exposed to light and outdoor conditions. Thanks to its cycloaliphatic structure, it can contribute to the long-term appearance of transparent, white or light-colored polyurethanes together with the appropriate polyol and additive system.
The two NCO groups in the molecule are not found in the same chemical environment. This difference can provide selective reaction behavior in controlled prepolymer synthesis. IPDI forms urethane bonds with polyols and urea bonds with primary or secondary amines.
IPDI is not only a monomer used directly in polyurethane synthesis. IPDI-based isocyanates, polyisocyanates, blocked crosslinkers, urethane acrylates, and NCO end prepolymers can be produced from this raw material.
In commercial high-purity IPDI grades, the NCO content can be found at approximately 37.5–37.8%. Purity, color, chlorine content and viscosity are important quality parameters in product selection.
Moisture control is essential during storage and processing, as IPDI can react with water. Unintended water contact can lead to the depletion of NCO groups, the formation of carbon dioxide, and the occurrence of defects such as bubbles in resin or coating systems.
The final performance depends not only on the IPDI, but also on the structure, functionality, NCO/OH ratio, catalyst and curing conditions of the polyol used.
WHAT IS ISOPHORONE DIISOCYANATE IPDI?
Isophorone Diisocyanate IPDI is a cycloaliphatic organic compound carrying two isocyanate functional groups. It is chemically identified by the name 3-Isocyanatomethyl-3,5,5-trimethylcyclohexyl Isocyanate. The commercial product is usually clear, colorless or slightly yellow and low viscosity liquid.
The molecule has a cyclohexane ring in its structure, which contains three methyl groups. One of the two NCO groups is directly attached to the ring, while the other is located on the isocyanatomethyl side group. This asymmetric structure causes the two NCO groups to exhibit different reactivity and can provide an advantage in controlled polyurethane syntheses.
IPDI has a nominal functionality of 2. It has a molecular weight of approximately 222.28 g/mol, a theoretical NCO equivalent weight of approximately 111.1 g/eq, and a theoretical NCO content of approximately 37.8%. A common technical specification for high-purity commercial products is that the NCO content is approximately 37.5–37.8% and the purity is at least 99.5%.
IPDI; It can react with polyether, polyester, polycarbonate and other hydroxyl function polyols. The choice of polyol significantly affects the flexibility, hardness, hydrolysis resistance and chemical resistance properties of the final polyurethane.
The cycloaliphatic structure can provide rigidity to the polyurethane rigid segment, while the absence of aromatic rings helps to reduce the tendency to light-induced yellowing. Therefore, IPDI can be considered in transparent, white and light color coating, elastomer and adhesive systems.
Monomeric IPDI is not the same product as a polyisocyanate hardener for the direct end user. The hardeners used in commercial two-component polyurethane paints are most often IPDI-derived polyisocyanates with higher functionality and lower free monomer content.
COMMON PRODUCT AND CHEMICAL NAMES
Isophorone Diisocyanate
IPDI
Isophorone Diisocyanate
3-Isocyanatomethyl-3,5,5-trimethylcyclohexyl Isocyanate
Monomeric Isophorone Diisocyanate
Isophorone Di-isocyanate
CAS NO, EC / EINECS NO AND CHEMICAL IDENTIFICATION
Product Name: Isophorone Diisocyanate IPDI
Turkish name: Isophorone Diisocyanate
Chemical name: 3-Isocyanatomethyl-3,5,5-trimethylcyclohexyl Isocyanate
Abbreviation: Isophorone Diisocyanate IPDI
CAS No: 4098-71-9
EC/EINECS No: 223-861-6
Molecular formula: C₁₂H₁₈N₂O₂
Molecular weight: Approximately 222.28 g/mol
Chemical class: Cycloaliphatic diisocyanate
Functionality: 2
Theoretical NCO content: Approximately 37.8%
Commercial NCO content: Approx. 37.5–37.8%
NCO equivalent weight: Approx. 111.1 g/eq
Purity: Approximately 99.5% ≥ in high-purity commercial products
Physical form: Clear, colorless to slightly yellow liquid
Its main functions: Polyurethane synthesis raw material, prepolymer raw material, polyisocyanate precursor, polyurethane dispersion raw material and special resin building block
Monomeric Isophorone Diisocyanate IPDI; IPDI trimer is not the same product as IPDI-based polyisocyanates and blocked IPDI derivatives. The product form must be verified at the time of purchase and formulation.
CHEMICAL STRUCTURE AND MOLECULAR PROPERTIES OF ISOPHORONE DIISOCYANATE IPDI
The main structure of Isophorone Diisocyanate IPDI is based on a substituted cyclohexane ring. The presence of three methyl groups affects the steric structure of the molecule and its behavior in polyurethane reactions.
The isocyanate groups in the molecule are not chemically equivalent. The fact that one of the groups is more accessible makes it possible to achieve selective transformation, especially in controlled urethane reactions.
This distinguishes Isophorone Diisocyanate IPDI from some diisocyanates that carry two functions in symmetric or very close reactivity. This difference can be used, especially when preparing functional prepolymer or intermediate.
The carbon atom in the NCO group has an electrophilic character due to the lack of electrons. Nucleophilic groups such as hydroxyl or amine attack this center and enable the formation of new bonds.
The reaction between alcohol and NCO leads to the formation of a urethane bond. This reaction forms the basis of polyurethane synthesis.
Primary and secondary amines react rapidly with isocyanates. The resulting urea bonds can affect hard segment properties and intermolecular interactions in polyurethane-urea resins.
Water may act as an undesirable or controlled reaction component with Isophorone Diisocyanate IPDI. After the initial reaction with water, carbon dioxide is released and the amine formed can react with the NCO group again.
Therefore, water ingress into a closed Isophorone Diisocyanate IPDI container can lead not only to a loss of chemical quality, but also to a pressure spike due to gas formation. Humidity control in storage and transfer systems is also important in this regard.
The cycloaliphatic nature of Isophorone Diisocyanate IPDI is a source of non-aromatic hard segments. The absence of aromatic chromophores helps to reduce the intense yellowing that occurs under light.
This property does not mean that the Isophorone Diisocyanate IPDI-based material is completely resistant to ultraviolet degradation. Actual outdoor performance is also affected by the polyol, additives, pigments, and stabilizer system.
The cyclic structure of Isophorone Diisocyanate IPDI can contribute to the tendency for hardness and higher glass transition temperature in the final polyurethane structure. Together with the low viscosity, this is particularly valuable in the development of high solids hard coatings.
The disordered molecular structure created by the methyl groups limits crystallization. Current manufacturer sources specify a solidification point of approximately -60 °C for Isophorone Diisocyanate IPDI.
This low solidification temperature provides a practical advantage in terms of storage and dosing. It may reduce the need for additional heating, especially when compared to other cycloaliphatic diisocyanates with a higher tendency to crystallize.
The broad compatibility of Isophorone Diisocyanate IPDI with resins and solvents is also important from a technical standpoint. Systems compatible with many common polyurethane solvents, such as esters, ketones, ether esters, and aromatic solvents, can be prepared.
Manufacturer data indicate that Isophorone Diisocyanate IPDI and its derivatives can also show remarkable compatibility with some aliphatic hydrocarbons. This property can provide additional flexibility in solvent selection and adjustment of solids ratio.
PHYSICAL AND CHEMICAL PROPERTIES OF ISOPHORONE DIISOCYANATE IPDI
Isophorone Diisocyanate IPDI is a clear and low viscosity liquid under normal conditions. Physical values may vary slightly depending on commercial quality, place of manufacture, measurement method and temperature.
General technical specifications:
Physical appearance: Clear liquid between colorless and slightly yellow
Odor: Mild but characteristic
Chemical character: Cycloaliphatic diisocyanate
Molecular formula: C₁₂H₁₈N₂O₂
Molecular weight: Approximately 222.28 g/mol
CAS No: 4098-71-9
EC/EINECS No: 223-861-6
Functionality: 2
NCO content: Approx. 37.5–37.8%
Purity: About ≥99.5%
NCO equivalent weight: Approx. 111.1 g/eq
Density: Approx. 1.058 g/cm³, 20 °C
Viscosity: Approx. 13–15 mPa·s, 23 °C
Colour: 10< APHA in a current high-purity commercial product
Refractive index: Approx. 1,483, 25 °C
Solidification/freezing point: About -60°C
Vapor pressure: Approx. 6.35 × 10⁻⁴ hPa, 20 °C
Flash point: Approx. 151 °C, closed cup
Autoignition temperature: Approx. 430 °C
Total chlorine: 10≤ ppm typical value in a current high-purity commercial product
NIOSH specific gravity value: Approx. 1.06
NIOSH vapor pressure: About 0.0003 mmHg
Behavior in water: Chemical reaction rather than physical dissolution
The low viscosity of Isophorone Diisocyanate IPDI is a key process advantage in polyurethane synthesis. Especially in prepolymer production, the lower initial viscosity can help facilitate mixing and heat transfer.
Very low vapor pressure indicates limited volatility at room temperature. However, in processes such as spraying, aerosol formation, or heating, respiratory exposure can still be significant.
The density is slightly higher than that of water. When mass-based dosing is preferred instead of volume in precise recipe calculations, the error that may arise from the effect of temperature on density can be reduced.
Its flash point is not as low as that of low boiling point solvents. However, the safe use of Isophorone Diisocyanate IPDI should not be evaluated solely on the basis of its flash point, as one of the main hazards of the product is its reactive diisocyanate structure.
These values are given for technical demonstration purposes. For commercial acceptance criteria, the current TDS and batch COA values of the purchased product should be taken as basis.
HOW DOES ISOPHORONE DIISOCYANATE IPDI WORK AT THE MOLECULAR LEVEL?
Isophorone Diisocyanate IPDI reacts with active hydrogen-bearing compounds, resulting in the formation of polyurethane or polyurethane-urea structures. During the reaction, the Isophorone Diisocyanate IPDI molecule becomes a chemical part of the final polymer network.
When the hydroxyl group present in the polyol combines with the NCO group, a urethane linkage occurs. The repeated reaction of the bifunctional polyol with the bifunctional Isophorone Diisocyanate IPDI can result in the formation of linear or high molecular weight polyurethane structures.
When the functionality of the polyol is greater than two, the network structure begins to develop. Thus, the cross-link density can be increased in coating, elastomer or thermoset polyurethane systems.
Amines can react more rapidly with NCO groups. This property can be especially evaluated in the chain extension stage of waterborne polyurethane dispersions.
The differential reactivity of the two NCO groups of Isophorone Diisocyanate IPDI is one of the key tools of controlled synthesis. Faster participation of one group in the reaction in favorable conditions can facilitate the preservation of the other NCO function for subsequent reaction steps.
This selectivity may decrease as the reaction temperature rises. Current Evonik technical data shows that selectivity can be more pronounced at temperatures below 50 °C under certain catalyst conditions.
The catalyst can be used to increase the reaction rate. Since cycloaliphatic diisocyanates react more slowly with hydroxyl groups than aromatic species, the choice of catalyst is important in many polyurethane formulations.
The molecular and reaction-level functions of Isophorone Diisocyanate IPDI can differ based on the application:
Creating a urethane bond with polyols
Forming urea bonds with amines
Creating a polyurethane chain
Prepare NCO tip prepolymer
To produce water-based polyurethane dispersion
Creating polyurethane-urea structures
Developing moisture-curing resins
To be a raw material in the production of Isophorone Diisocyanate IPDI isocyanurates
Isophorone Diisocyanate For Use In The Preparation Of IPDI Polyisocyanates
Producing blocked crosslinker
Preparing urethane acrylate oligomers
Being a building block for radiation-curing resins
Producing polyurethane intermediates with silane function
To be used in the preparation of urethane alkyds
Forming the light-resistant polyurethane rigid segment
Contributing to the improvement of film hardness and chemical resistance
IN WHICH SECTORS IS ISOPHORONE DIISOCYANATE IPDI USED?
Isophorone Diisocyanate IPDI; It is an important intermediate raw material used in the production of coatings, adhesives, sealants, elastomers, leather, textiles and special polyurethane resins. The way in which it is used varies according to whether the monomeric Isophorone Diisocyanate IPDI is used directly as a synthesis raw material or its derivative is used in the final formulation.
Main areas of use:
Automotive OEM coatings
Automotive refinish coatings
Commercial vehicle wraps
Transparent topcoats
Industrial metal coatings
Outdoor protective coatings
Wood varnishes
Transparent wood veneers
Plastic surface coatings
High solids polyurethane coatings
Waterborne polyurethane dispersions
Solvent-based polyurethane resins
Polyurethane adhesives
Water-based adhesives
Shoe adhesives
Laminating adhesives
Automotive interior trim adhesives
Reactive hot melt adhesives
Moisture-curing adhesives
Construction adhesives
Polyurethane sealants
Automotive sealants
Construction grouts
Polyurethane elastomers
Light-colored cast elastomers
RIM polyurethane systems
Artificial leather production
Natural leather surface coatings
Textile coatings
Flexible polyurethane films
Protective membranes
Urethane acrylates
UV-curing coatings
UV-curing inks
Radiation curing oligomers
Silane terminated polyurethanes
Hybrid adhesives and sealants
Production of Isophorone Diisocyanate IPDI trimer
Production of Isophorone Diisocyanate IPDI polyisocyanate
Blocked Isophorone Diisocyanate IPDI derivatives
Urethane modified alkyd resins
Flexible casting resins
Tool resins
Isophorone Diisocyanate IPDI is especially important in the preparation of light and weather resistant polyurethane systems. Current manufacturer sources show water-based polyurethane dispersions, coating raw materials, adhesives, moisture-curing prepolymers and urethane acrylates among the important areas of use.
The same Isophorone Diisocyanate IPDI performance criteria are not required in every application. While color and yellowing resistance are at the forefront in transparent paint production, NCO content, reaction selectivity and viscosity may be more critical in prepolymer production.
PAINT, COATING, POLYURETHANE AND RESIN APPLICATIONS OF ISOPHORONE DIISOCYANATE IPDI
The paints and coatings industry is one of the most important uses of Isophorone Diisocyanate IPDI. However, it should be noted that in commercial coatings, monomeric Isophorone Diisocyanate IPDI is often the starting raw material for polyisocyanate or resin production rather than directly as a final hardener.
Monomeric Isophorone Diisocyanate can be converted to higher function crosslinkers by IPDI controlled trimerization or adduct reactions. These derivatives can be used in two-component polyurethane coatings in combination with hydroxyl-function acrylic or polyester resins.
Possible functions of Isophorone Diisocyanate IPDI in coating and resin applications include:
Producing light-resistant polyurethane resin
To prepare systems with high outdoor resistance
Reducing yellowing on transparent films
Maintaining the appearance of white and light-colored coatings
Isophorone Diisocyanate produce IPDI-based polyisocyanates
Preparing isocyanurate type hardeners
Producing blocked polyisocyanates
Preparing water-based polyurethane resins
Producing low-viscosity prepolymers
Developing high-solids coating resins
Preparing urethane acrylate
Improving chemical resistance
Increasing film stiffness
Supporting abrasion and scratch resistance
Contributing to shine preservation
Helping to maintain the exterior appearance in automotive coatings
Automotive OEM and refinish coatings are classic uses of Isophorone Diisocyanate IPDI derivatives. For transparent topcoats, it is an important performance criterion that the coating changes color as little as possible under sunlight.
Isophorone Diisocyanate IPDI-based isocyanurates can be considered as high-function crosslinkers in such systems. Conversion to polyisocyanate structure also makes it possible to reduce the level of free monomers in the final hardener.
Yellowing resistance in wood varnishes is particularly important on light-colored or surfaces where the natural appearance needs to be preserved. Isophorone Diisocyanate IPDI-based aliphatic or cycloaliphatic polyurethane coatings can be used for this purpose.
Hardness and flexibility need to be balanced in plastic coatings. Isophorone Diisocyanate IPDI hard segment can be combined with the appropriate soft segment selection to balance scratch resistance and flexural strength.
Resin viscosity is a significant limiting factor in high-solids coating technology. Isophorone Diisocyanate IPDI's low viscosity and suitability for selective prepolymer synthesis can be evaluated in the design of systems requiring lower solvents.
Urethane acrylates are another important product group. Isophorone Diisocyanate IPDI can be reacted with hydroxyl-function acrylate compounds to produce oligomers that can be cured with UV or electron beam.
These resins can combine the mechanical performance of polyurethane bonds with rapid radiation curing. For UV coatings that require transparency and low yellowing, Isophorone Diisocyanate IPDI-based urethane acrylates may be preferred.
As a result of the reaction of Isophorone Diisocyanate IPDI with alkyd resins, urethane alkyd or urethane oils can be prepared. This modification can have a positive effect on yellowing resistance, drying and hardness development.
Blocked Isophorone Diisocyanate IPDI or Isophorone Diisocyanate IPDI derivatives can be used as crosslinkers in one-component furnace systems. Temporarily sealing the reactive NCO groups makes it possible to store the resin and hardener in the same packaging.
During baking, the system becomes reactive and cross-linking occurs. Coil coating, metal packaging coatings, and different industrial baking paints are among the areas where this approach can be evaluated.
USE OF ISOPHORONE DIISOCYANATE IPDI IN ADHESIVE, SEALING, ELASTOMER AND WATER-BASED POLYURETHANE APPLICATIONS
Isophorone Diisocyanate IPDI can be used in the production of waterborne polyurethane dispersion, NCO tip prepolymer and reactive binder in adhesive technology. Its low prepolymer viscosity can be advantageous in terms of water dispersion and the development of systems with low co-solvents.
Suitable IPDI-based polyurethane dispersions in footwear, laminating and automotive interior trim adhesives can be considered to provide flexibility and adhesion. The final performance depends on the polyol structure, soft segment, chain extender and cross-linking system.
In reactive hot melt adhesives, the prepolymer is applied in a hot state; cooling provides initial adhesion, while the ongoing reaction with moisture improves the final strength. In moisture-curing mastics and adhesives, IPDI prepolymers with NCO tips can react with atmospheric moisture to form a network structure.
The low yellowing tendency of IPDI-based prepolymers can be advantageous in visible joints and light-colored adhesive or sealant products. In silane-terminated polyurethane systems, the IPDI-prepared NCO tip prepolymer can be terminated with appropriate silane-functional compounds.
In polyurethane elastomers, IPDI can be used especially in applications where light color, light resistance or outdoor appearance is important. In artificial leather, natural leather and coated textile systems, it can contribute to providing flexibility, abrasion resistance and color stability together.
IS ISOPHORONE DIISOCYANATE IPDI USED IN FOOD, COSMETIC AND PHARMACEUTICAL APPLICATIONS?
Isophorone Diisocyanate IPDI is the reactive raw material mainly used in the synthesis of industrial polyurethane. It is not directly used as a food additive, flavoring agent, cosmetic raw material or pharmaceutical excipient.
Conformity assessment for food contact coatings or adhesives should not be made according to the general name of the monomer, but according to the completed polymer system, the amount of free monomer, the migration results and the current food contact legislation of the target market.
In cosmetics and personal care formulations, monomeric IPDI is not a standard ingredient. It should not be considered for use in direct-to-consumer cosmetics formulation due to its reactive NCO groups.
The use of polyurethane in medical devices also does not mean that monomeric IPDI is directly suitable for medical use. The biocompatibility of the final polymer, its extractable substances, and the amount of monomer remaining must be evaluated separately.
The primary functions of IPDI in industrial applications include:
Polyurethane synthesis
NCO tip prepolymer production
Production of water-based polyurethane dispersion
Polyurethane-urea synthesis
IPDI trimer and polyisocyanate production
Production of blocked polyisocyanate
Production of adhesives and mastic resins
Elastomer synthesis
Production of leather and textile coating resin
Urethane acrylate synthesis
Production of UV-cured resin
Production of silane-terminated polyurethane
Transparent and light-colored polyurethane resins
Protective coatings with high outdoor resistance
The NCO/OH ratio is one of the basic calculation parameters in polyurethane synthesis. The hydroxyl number, functionality and moisture of the polyol directly affect the required amount of IPDI. Reaction temperature, catalyst type and feed rate are also important for controlled synthesis.
In industrial systems, product purity, NCO content, color, viscosity, chlorine values, polyol type, NCO/OH ratio, reaction temperature, residual NCO, free IPDI and prepolymer viscosity should be evaluated together. TDS, SDS and batch COA data should be checked before the process.
WHAT PROBLEMS CAN ISOPHORONE DIISOCYANATE IPDI HELP SOLVE?
Isophorone Diisocyanate IPDI; It can help meet various technical needs related to color stability, outdoor performance, pre-polymer processability, and controlled polyurethane synthesis. However, performance depends on the design of the entire resin system.
Significant yellowing of aromatic polyurethanes
In polyurethanes containing MDI or TDI, ultraviolet light can lead to color change over time. The cycloaliphatic nature of IPDI can help reduce this tendency in transparent and light-colored products.
Loss of color and gloss in outdoor coatings
IPDI-derived polyisocyanates can contribute to color and gloss retention when used in conjunction with the appropriate outdoor resin and stabilizer package.
High prepolymer viscosity
IPDI's low viscosity and reaction selectivity can help develop polyurethane intermediates that are more easily pumped and processed.
High co-solvent requirement in waterborne polyurethane dispersion
Lower viscosity IPDI prepolymers can support reducing the amount of co-solvent required during the dispersing phase into water.
High starting color for transparent or white products
High-purity IPDI grades with low color value can help prepare lighter-colored polyurethane resins.
Color change in light-colored sealants cured with moisture
IPDI-based prepolymers can provide better color retention in visible and light-colored sealants than aromatic diisocyanates.
Yellow tint in UV-cured resins
IPDI-based urethane acrylates can be evaluated in UV systems targeting low color and high light resistance.
Insufficient hardness or chemical resistance in the coating
IPDI-derived high-function polyisocyanates can contribute to the improvement of film stiffness and chemical resistance by increasing cross-link density with appropriate hydroxyl-function resins.
It should not be assumed that every commercial IPDI product will produce the same reaction result. Purity, color, chlorine, NCO content, and actual reaction behavior should be compared when changing suppliers.
THINGS TO CONSIDER WHEN USING ISOPHORONE DIISOCYANATE IPDI
Humidity control is one of the basic process requirements when using Isophorone Diisocyanate IPDI. Since NCO groups can easily react with water, it is important that the raw materials, equipment and solvents are dry.
The following issues should be considered when using Isophorone Diisocyanate IPDI:
It should be verified that the product is monomeric Isophorone Diisocyanate IPDI.
The CAS number should be checked.
The purity value should be examined.
The NCO content should be checked.
The color value should be evaluated.
Total chlorine should be checked.
Hydrolysis may be checked if chlorine is required.
The polyol hydroxyl number should be known.
Polyol functionality should be considered.
The moisture content of the polyol should be controlled.
It should be ensured that the solvents are dry.
NCO/OH equivalent calculation should be made.
The reactor must be kept dry.
The Isophorone Diisocyanate IPDI feed rate should be checked.
The reaction temperature should be monitored.
Exothermic behavior should be considered.
The type of catalyst should be selected according to the application.
The amount of catalyst should be optimized.
The remaining amount of NCO should be analyzed.
The amount of free Isophorone Diisocyanate IPDI should be measured as needed.
The pre-polymer viscosity should be followed.
Moisture ingress must be prevented during storage.
Transfer equipment must be kept dry.
Splashing and aerosol formation should be reduced.
TDS should be examined.
SDS should be examined.
Batch values must be verified via COA.
Monomeric Isophorone Diisocyanate IPDI and Isophorone Diisocyanate IPDI trimer or Isophorone Diisocyanate IPDI-based polyisocyanates should not be used directly interchangeably. Functionality, equivalent weight, viscosity, and free monomer levels are different.
Feeding and temperature control are important in large-scale syntheses because the polyol reaction with Isophorone Diisocyanate IPDI is exothermic. Insufficient heat removal can cause the reaction temperature to rise faster than planned.
Applications that generate spraying or aerosols are particularly important in terms of exposure. Current SDS, workplace risk assessment and applicable diisocyanate legislation should be taken as a basis.
INITIAL FORMULATION APPROACHES FOR ISOPHORONE DIISOCYANATE IPDI
The following examples are laboratory starting points to illustrate how Isophorone Diisocyanate IPDI can be evaluated during formulation and process development. These are not validated commercial recipes or final formulations ready for use.
Actual ratios should be recalculated based on the hydroxyl number of the polyol used, the actual NCO content of IPDI, the targeted NCO/OH ratio, and the final application requirements.
EXAMPLE 1: NCO/OH RATIO SCREENING IN ISOPHORONE DIISOCYANATE IPDI/POLYOL PREPOLYMER
Purpose: To compare the effect of different NCO/OH ratios on prepolymer viscosity, amount of residual NCO, free monomer, and final polyurethane performance.
Starting components:
Sample 1 – target NCO/OH approx. 1.5:
Polyol, approx. 56 mg KOH/g OH: 85.72%
Isophorone Diisocyanate IPDI: 14.26%
Catalyst: 0.02%
Total: 100%
Sample 2 – target NCO/OH approx. 1.8:
Polyol, approx. 56 mg KOH/g OH: 83.34%
Isophorone Diisocyanate IPDI: 16.64%
Catalyst: 0.02%
Total: 100%
Sample 3 – target NCO/OH approx. 2.0:
Polyol, approx. 56 mg KOH/g OH: 81.83%
Isophorone Diisocyanate IPDI: 18.15%
Catalyst: 0.02%
Total: 100%
Sample 4 – target NCO/OH approx. 2.2:
Polyol, approx. 56 mg KOH/g OH: 80.37%
Isophorone Diisocyanate IPDI: 19.61%
Catalyst: 0.02%
Total: 100%
Application approach:
The actual hydroxyl value and moisture content of the polyol are checked before the reaction.
The actual NCO percentage of IPDI is taken from the COA document.
The above percentages are only the sample starting calculation for a polyol with a KOH/g OH of about 56 mg.
When different polyol is used, the IPDI percentage is recalculated.
Each sample compares the prepolymer viscosity, residual NCO amount, color, and free IPDI amount where required.
EXAMPLE 2: ISOPHORONE DIISOCYANATE IPDI BASED WATER BASED POLYURETHANE DISPERSION DEVELOPMENT SCAN
Objective: To evaluate dispersion stability, particle size, film hardness, flexibility, and water resistance in an initial PUD formulation containing IPDI.
Starting components:
Polyol: 28.00%
Isophorone Diisocyanate IPDI: 11.00%
Internal hydrophilic component: 2.50%
Neutralizing agent: 1.90%
Chain extender: 1.40%
Co-solvent: 5.20%
Deionized water: 50.00%
Total: 100%
Application approach:
The humidity of polyol and other reactive components is controlled.
The amount of IPDI is verified based on the actual OH value of the polyol used and the targeted NCO/OH ratio.
The prepolymer is followed according to the target NCO value.
After the ionic groups are neutralized, the system is taken into the water phase in a controlled manner.
After chain extension, particle size, viscosity, pH, and storage stability are compared.
A standard film is prepared and hardness, flexibility, adhesion, water and abrasion resistance are evaluated.
EXAMPLE 3: ISOPHORONE DIISOCYANATE IPDI BASED LIGHT RESISTANT POLYURETHANE COATING SCAN
Objective: To evaluate film hardness, flexibility, chemical resistance and color stability in a two-component polyurethane coating containing IPDI-based low monomer polyisocyanate.
Starting components:
Resin with hydroxyl function: 55.00%
IPDI-based low-monomer polyisocyanate: 20.00%
Suitable solvent mixture: 22.50%
Flow and surface regulating additive: 2.00%
Catalyst: 0.40%
Defoamer: 0.10%
Total: 100%
Application approach:
The actual OH value of the hydroxyl function resin is determined.
The stiffener ratio of polyisocyanate is verified over the actual NCO content.
The 20% polyisocyanate value is for baseline screening only and should be corrected for the target NCO/OH ratio.
The components are mixed homogeneously just before application.
Initial viscosity and usage time are monitored.
Drying, hardness, adhesion, chemical resistance, and impact or bending performance are evaluated on the standard panel.
In an accelerated UV or weathering test, color change and gloss retention are compared.
ALTERNATIVES AND COMPARISONS OF ISOPHORONE DIISOCYANATE IPDI
The choice of alternative for Isophorone Diisocyanate IPDI should not be based solely on price or NCO percentage. Molecular structure, reactivity, color stability, viscosity, equivalent weight, and targeted polyurethane properties should be evaluated together.
ISOPHORONE DIISOCYANATE IPDI AND HEXAMETHYLENE DIISOCYANATE (HDI)
HDI is an aliphatic diisocyanate with a linear structure. Isophorone Diisocyanate IPDI, on the other hand, is a cycloaliphatic molecule with a cyclic and more steric hindrance.
Both raw materials can be used in polyurethanes that require light resistance. However, since the final rigid segment structures are not the same, their hardness, flexibility and reaction behavior differ.
The cycloaliphatic ring of Isophorone Diisocyanate IPDI can contribute to higher rigidity. The linear chain of HDI can facilitate the preparation of more flexible polyurethane structures in suitable systems.
Mixtures of Isophorone Diisocyanate IPDI and HDI based polyisocyanates can also be used in coating technology. Thus, the desired balance between properties such as hardness, drying, viscosity and flexibility can be achieved.
Two products should not be substituted directly at the same weight. Equivalent calculation should be made again according to the actual NCO content.
ISOPHORONE DIISOCYANATE IPDI AND H12MDI
H12MDI is another cycloaliphatic diisocyanate known as hydrogenated MDI or dicyclohexylmethane diisocyanate. Isophorone Diisocyanate has a larger and two-ring molecular structure than IPDI.
H12MDI can also be used in polyurethanes with high light resistance. It can be used especially in thermoplastic polyurethanes, elastomers and special dispersion systems.
The low viscosity and very low solidification temperature of Isophorone Diisocyanate IPDI can provide a process advantage. H12MDI can provide different rigid segment arrangement and mechanical performance.
The formulation must be recalculated as the equivalent weights and physical behaviors of the two products are different.
ISOPHORONE DIISOCYANATE IPDI AND MDI
MDI is in the aromatic diisocyanate class and has a wide range of uses in the polyurethane industry. Foam, adhesive, insulation, composite and elastomer systems are among these usage areas.
MDI generally shows higher reactivity than Isophorone Diisocyanate IPDI. This can be advantageous in processes that require a rapid reaction.
Due to the aromatic structure, MDI-based polyurethanes may exhibit significant yellowing under light. Therefore, Isophorone Diisocyanate IPDI may be a more suitable option for transparent and light-colored outdoor coatings.
MDI can be more economically advantageous in most large volume applications. Isophorone Diisocyanate IPDI is preferred in systems where appearance preservation and special polyurethane performance are required.
MDI and Isophorone Diisocyanate IPDI do not have the same equivalent weight. When switching from one product to another, NCO/OH calculation and reaction conditions should be redetermined.
ISOPHORONE DIISOCYANATE IPDI AND TDI
TDI is aromatic and Isophorone Diisocyanate is a more volatile diisocyanate than IPDI. It is widely used in flexible polyurethane foam and some elastomer or prepolymer systems.
Isophorone Diisocyanate IPDI shows lower volatility and cycloaliphatic structure. It has a different technical position in polyurethane applications where light and color stability are important.
While TDI reacts faster, controlled reactivity and catalyst use may become more important in Isophorone Diisocyanate IPDI. Process conditions should therefore not be transferred directly.
The molecular weight and NCO equivalent of the two products are different. Direct weight-by-weight substitution does not give accurate results.
ISOPHORONE DIISOCYANATE IPDI AND ISOPHORONE DIISOCYANATE IPDI TRIMMER
Monomeric Isophorone Diisocyanate IPDI and Isophorone Diisocyanate IPDI trimer are not the same commercial product. Monomeric Isophorone Diisocyanate IPDI is the starting raw material bearing two NCO groups per molecule.
The Isophorone Diisocyanate IPDI trimer is prepared as a result of the controlled reaction of Isophorone Diisocyanate IPDI molecules to form an isocyanurate ring. The resulting product shows higher functionality.
This high functionality makes Isophorone Diisocyanate IPDI trimer effective crosslinker in two-component polyurethane coatings. At the same time, the amount of free monomer in commercial trimer products can be kept much lower than in monomeric Isophorone Diisocyanate IPDI.
The primary task of monomeric Isophorone Diisocyanate IPDI is to be the raw material for the synthesis of such crosslinkers or polyurethane intermediates. Trimer, on the other hand, can be incorporated into the formulation as the final coating hardener.
Therefore, monomer and trimer cannot be used in the same amount or in the same way.
ISOPHORONE DIISOCYANATE IPDI AND BLOCKED ISOPHORONE DIISOCYANATE IPDI
In blocked Isophorone Diisocyanate IPDI products, reactive isocyanate functions are temporarily reacted with other groups. Thus, NCO reactivity is reduced at low temperature or during storage.
This approach allows for the preparation of single-component furnace systems. The resin and crosslinker can be kept together in the same product for a longer period of time.
When sufficient temperature is reached, the cross-linking reaction becomes active. Blocked Isophorone Diisocyanate IPDI derivatives can therefore be evaluated in industrial baking paints and some powder coating technologies.
Monomeric Isophorone Diisocyanate IPDI carries free NCO groups and does not have this storage behavior. The two products should not be used directly with the same application logic.
QUALITY CONTROL AND PURCHASING CRITERIA FOR ISOPHORONE DIISOCYANATE IPDI
When purchasing Isophorone Diisocyanate IPDI, it is not enough to make a decision based solely on the product name or price. Values such as NCO content, purity, color, chlorine amount, and viscosity can affect the consistency of subsequent polyurethane synthesis.
Recommended information to review before purchasing:
Product name and manufacturer
Full chemical identity
CAS number
EC/EINECS number
Whether Monomeric Isophorone Diisocyanate IPDI
Purity
NCO content
NCO equivalent weight
Total chlorine
Hydrolysis can chlorine
Color value
Viscosity
Density
Refractive index
Humidity value, if any
Storage conditions
Shelf life
Packaging Type
Net quantity
Production date
Batch number
Information of origin
TDS
SDS
COA
REACH information
Educational and restriction information on the use of diisocyanate
The COA shows the actual analysis results of a specific batch of Isophorone Diisocyanate IPDI. Batch-wise verification of NCO content is important for sensitive stoichiometric accounts.
TDS describes the general technical specifications of the product, its standard specification and the manufacturer's recommended uses. SDS is the basic document for health, safety, storage, exposure and emergency information.
These documents are not interchangeable. During raw material approval, TDS/COA should be reviewed together for product identity and technical performance, and up-to-date SDS for safety assessment.
The color value is especially important for transparent and white polyurethane resins. A high initial color can contribute to the development of undesirable tones in the final film.
Total chlorine and hydrolysis can provide additional information about chlorine production quality. Chlorine-containing impurity levels should be checked, especially in sensitive catalysis systems.
When switching to a new manufacturer or a new Isophorone Diisocyanate IPDI grade grade, comparative laboratory synthesis may be useful. Reaction time, prepolymer viscosity, color, NCO value and free monomer level can be compared.
STORAGE AND HANDLING OF ISOPHORONE DIISOCYANATE IPDI
Isophorone Diisocyanate IPDI should be kept in the conditions recommended by the manufacturer, in its original and tightly closed packaging, in dry and controlled storage areas.
It is important to protect packaging from the ingress of water and atmospheric moisture, as the reaction with moisture can degrade product quality and create carbon dioxide.
Storage tanks, pumps, valves, and transfer lines should be selected from dry and chemically compatible materials.
When the product is not in use, the packaging should be tightly closed.
The manufacturer's temperature recommendations should be followed, as long-term storage at high temperatures may increase color formation or unwanted side reactions.
The product can remain liquid in cold conditions due to its low solidification temperature, but the actual storage limit should be checked from the TDS and SDS document of the relevant commercial grade.
IPDI containers contaminated with water may develop pressure due to the formation of carbon dioxide. In such a case, it should not be treated like a normal closed product container and the supplier's emergency procedure should be applied.
Transport classification and packaging requirements must be verified on the current SDS.
ISOPHORONE DIISOCYANATE IPDI SAFETY INFORMATION
As Isophorone Diisocyanate IPDI is a reactive diisocyanate, safe use should be based on up-to-date SDS and workplace risk assessment.
The risk of skin and respiratory sensitisation should be taken into account.
Exposure to steam, aerosols and splashes should be reduced as much as possible.
Closed transfer systems and appropriate local suction ventilation should be preferred.
Spraying processes require special control, as they can significantly increase inhalation exposure.
Protective gloves, eye and face protection and appropriate work clothing should be used.
Whether respiratory protection is required should be determined according to the process conditions and SDS.
In the European Union, there are training requirements for the professional and industrial use of products containing diisocyanates above certain concentrations. Current legal obligations must be followed separately by the business.
The low vapor pressure of IPDI does not mean that there is no risk of exposure. Exposure control is important, especially in heating and aerosol-forming processes.
WHAT TO CONSIDER WHEN BUYING ISOPHORONE DIISOCYANATE IPDI
In the supply of Isophorone Diisocyanate IPDI, it should first be determined whether the product is monomeric IPDI and for which polyurethane system it will be used.
The following information should be clarified before purchasing:
Use sector
Final application
Monomeric IPDI requirement
Purity demanded
NCO content
NCO equivalent weight
Total chlorine
Hydrolysis can chlorine
Color
Viscosity
Density
Packaging type
Order quantity
Manufacturer
Origin
Storage conditions
Shelf life
TDS
SDS
COA
REACH and related legislation information
Where the existing product is to be substituted, the existing TDS and COA
The price of Isophorone Diisocyanate IPDI may vary depending on purity, manufacturer, NCO content, chlorine specification, packaging, order volume and current logistics conditions. It may not be appropriate to compare two products that do not appear to be technically equivalent based on kilogram price alone.
ISOPHORONE DIISOCYANATE IPDI SUPPLY FROM ATAMAN KIMYA
Isophorone Diisocyanate IPDI; It is an important cycloaliphatic diisocyanate raw material evaluated in paint and coating, polyurethane resin, adhesive, sealing, elastomer, textile and leather systems. It is important for companies planning to purchase the product to determine the technical specifications suitable for the application before ordering.
Companies that want to get information about the supply of Isophorone Diisocyanate IPDI from Ataman Kimya can request information about product suitability, current supply conditions, packaging options and offer by sharing their usage areas and target technical specifications.
The current stock status, manufacturer, origin, quality class, purity, NCO content, packaging and other specifications of the product should be confirmed from Ataman Kimya before ordering.
Sharing the following information in the request for quotation facilitates the evaluation of the right Isophorone Diisocyanate IPDI product:
Use sector and end application
Monomeric Isophorone Diisocyanate IPDI Requirement
Type of polyurethane to be produced
Minimum purity requested
Requested NCO content
Total chlorine requirement
Hydrolysis can chlorine requirement
Color requirement
Viscosity requirement
Polyol or resin system used
Estimated order quantity
Type of packaging requested
Requested technical documents
TDS or COA information of the current product, if applicable
FREQUENTLY ASKED QUESTIONS ABOUT ISOPHORONE DIISOCYANATE IPDI
What is ISOPHORONE DIISOCYANATE IPDI?
Isophorone Diisocyanate IPDI is a cycloaliphatic diisocyanate containing two reactive NCO groups. It is used in the production of polyurethane resins, coatings, adhesives, sealants, elastomers, and dispersions.
What is the CAS number of ISOPHORONE DIISOCYANATE IPDI?
CAS No is 4098-71-9.
What is the EC number of ISOPHORONE DIISOCYANATE IPDI?
EC/EINECS No is 223-861-6.
What is the molecular formula and molecular weight of ISOPHORONE DIISOCYANATE IPDI?
Its molecular formula is C₁₂H₁₈N₂O₂ and its molecular weight is approximately 222.28 g/mol.
How many NCO groups does ISOPHORONE DIISOCYANATE IPDI contain?
It contains two NCO groups per molecule and has a nominal functionality of 2.
What is the NCO content of ISOPHORONE DIISOCYANATE IPDI?
The theoretical value is approximately 37.8%. In high-purity commercial products, it can be seen in the range of approximately 37.5–37.8%.
What is the NCO equivalent weight of ISOPHORONE DIISOCYANATE IPDI?
It is approximately 111.1 g/eq.
Is ISOPHORONE DIISOCYANATE IPDI liquid?
It is a clear and colorless to slightly yellow liquid with low viscosity at room temperature.
Why is ISOPHORONE DIISOCYANATE IPDI used in the production of polyurethane?
The NCO groups react with the OH groups in the polyols to form urethane bonds and enable the polyurethane structure to form.
Do the two NCO groups of ISOPHORONE DIISOCYANATE IPDI have the same reactivity?
Due to the asymmetric structure of the molecule, the two NCO groups may show different reactivity, and this property can be used in controlled syntheses.
What is the significant advantage of ISOPHORONE DIISOCYANATE IPDI over MDI and TDI?
Since it does not contain aromatic rings, it may have a lower tendency to yellow under light than MDI and TDI-based systems.
Are ISOPHORONE DIISOCYANATE IPDI and HDI the same product?
HDI has linear aliphatic structure and IPDI has cycloaliphatic structure. Reactivity, equivalent weight and final polyurethane properties are different.
What is ISOPHORONE DIISOCYANATE IPDI trimer?
It is a higher functioning polyisocyanate prepared by the reaction of IPDI molecules to form an isocyanurate structure. It is not the same product as monomeric IPDI.
Is ISOPHORONE DIISOCYANATE IPDI used in waterborne polyurethane dispersions?
It is one of the diisocyanates used in PUD technology due to its low viscosity prepolymer formation and light resistance.
Is ISOPHORONE DIISOCYANATE IPDI used in the production of adhesives and sealants?
It can be used in the preparation of water-based dispersions, reactive hot melt systems, moisture-curing prepolymers, and sealing resins.
Does ISOPHORONE DIISOCYANATE IPDI react with water?
Water consumes NCO groups, and as a result of the reaction, carbon dioxide and urea structures can form.
Why should ISOPHORONE DIISOCYANATE IPDI be protected from moisture?
Moisture can lead to NCO loss, gas formation, and undesirable polyurea formation.
What is the commercial purity of ISOPHORONE DIISOCYANATE IPDI?
For high-purity commercial products, a purity of at least 99.5% is a common specification.
What is the viscosity and density of ISOPHORONE DIISOCYANATE IPDI?
In current commercial data, the viscosity is about 13–15 mPa·s and the density is about 1.058 g/cm³.
Is ISOPHORONE DIISOCYANATE IPDI a raw material for food or cosmetics?
Monomeric IPDI is not a direct food additive, flavoring agent, or standard cosmetic raw material.
What documents should be required when purchasing ISOPHORONE DIISOCYANATE IPDI?
TDS, SDS, and COA are essential documents. REACH and other regulatory documents should also be evaluated according to the application.
How should ISOPHORONE DIISOCYANATE IPDI be stored?
It should be stored in dry, tightly sealed, and chemically appropriate packaging, protected from moisture and reactive substances, under the conditions recommended by the supplier.
ISOPHORONE DIISOCYANATE IPDI – TECHNICAL SUMMARY
Isophorone Diisocyanate IPDI, known as Isophorone Diisocyanate in Turkish, is a cycloaliphatic diisocyanate with the molecular formula C₁₂H₁₈N₂O₂. The molecular weight of the product, defined by CAS No 4098-71-9 and EC No 223-861-6, is approximately 222.28 g/mol.
Isophorone Diisocyanate IPDI contains two reactive NCO groups and has a nominal functionality of 2. The theoretical NCO content is approximately 37.8%, and NCO in the range of approximately 37.5–37.8% and a purity of at least 99.5% can be seen in high-purity commercial products.
The fact that the two isocyanate groups in the molecule have different steric environments provides reaction selectivity. This property can be especially evaluated in the controlled production of low viscosity and low free monomer prepolymers.
The cycloaliphatic structure helps Isophorone Diisocyanate IPDI-based polyurethanes to have a lower tendency to yellow under light than aromatic diisocyanate systems. Therefore, Isophorone Diisocyanate IPDI chemistry is important in automotive, wood, plastic, leather and outdoor coating applications.
Isophorone Diisocyanate IPDI; It can be used in the preparation of polyurethane coating resins, waterborne polyurethane dispersions, adhesives, sealants, elastomers, urethane acrylates, moisture-curing prepolymers, and silane-terminated polyurethanes.
Isophorone Diisocyanate IPDI is also the raw material for the production of higher functioning polyisocyanates. Isophorone Diisocyanate IPDI trimers or other polyisocyanate derivatives can be used as hardeners in two-component polyurethane coatings, but it is not the same product as monomeric Isophorone Diisocyanate IPDI.
Current commercial product data give a density of approximately 1.058 g/cm³, viscosity of approximately 13–15 mPa·s, refractive index of approximately 1.483 and closed cup flash point of approximately 151 °C.
When purchasing Isophorone Diisocyanate IPDI, NCO content, purity, color, total chlorine, hydrolyzable chlorine if necessary, viscosity and batch-based COA values should be examined. Especially in sensitive polyurethane synthesis, the actual NCO value can be used in stoichiometric calculations.
Since Isophorone Diisocyanate IPDI reacts with water, it is important that storage, transfer and synthesis equipment is dry. The current SDS is the basic document for exposure control, personal protective equipment, storage and emergency applications.
It is recommended that companies planning to supply Isophorone Diisocyanate IPDI from Ataman Kimya confirm the current product and offer conditions by sharing the usage area, monomeric Isophorone Diisocyanate IPDI requirement, requested purity and NCO content, color and chlorine limits, packaging quantity and technical document needs.
