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Dual-Mechanism Cationic Photoinitiator for UV-Curable Inks, Coatings, and Deep-UV Photoresists: 4-Isobutylphenyl-4'-methylphenyliodonium Hexafluorophosphate (Irgacure 250) CAS# 344562-80-7
Created on 10.06
4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate (CAS# 344562-80-7), also known as (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate, Irgacure 250, Omnicat 250, or HRcure-250, is a high-performance diaryliodonium salt photoinitiator. Its molecular formula is C₁₇H₂₀F₆IP, and its molecular weight is 496.21 g/mol.
The compound consists of a central iodine(III) cation bearing two different aryl groups—a p-tolyl group and a p-isobutylphenyl group—paired with a hexafluorophosphate (PF₆⁻) counteranion. This asymmetric diaryliodonium structure, together with the non-nucleophilic PF₆⁻ anion, gives the product excellent photochemical reactivity, thermal stability, and deep through-cure performance.
It is widely used in UV-curable inks, coatings, adhesives, 3D printing resins, photoresists, and electronic materials. Its dual homolytic/heterolytic photolysis mechanism allows it to initiate both cationic and free-radical polymerization, making it a valuable photoinitiator for hybrid curing systems.
Quick Overview
Property | Typical Value |
Product Name | 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate |
CAS Number | 344562-80-7 |
Synonyms | Irgacure 250; Omnicat 250; HRcure-250 |
Molecular Formula | C₁₇H₂₀F₆IP |
Molecular Weight | 496.21 g/mol |
Appearance | Yellow to brown clear liquid |
Standard Supply Form | 75% solution in propylene carbonate |
Purity | ≥98% (solid basis) |
Density | 1.485 g/cm³ |
Viscosity | 460 cps at 25°C |
UV Absorption Maximum | 240–245 nm |
Solubility | Soluble in cationic polymerizable monomers, methanol, chloroform; poor solubility in non-polar solvents |
Thermal Stability | Good thermal stability under recommended storage conditions |
Storage | Cool, dark place; protect from light and moisture |
GHS Classification | Warning; H315, H319, H335 |
Transport | Not classified as hazardous material for DOT/IATA transport under standard conditions |
Why This Photoinitiator Is Different
The main advantage of 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate is its dual photolysis mechanism.
When exposed to UV light, the diaryliodonium cation undergoes heterolytic cleavage to generate a superacid, HPF₆. This acid initiates cationic polymerization of epoxy and oxetane monomers. At the same time, homolytic cleavage produces active aryl radicals that can initiate free-radical polymerization of acrylate monomers.
This dual curing capability is important for modern UV formulations. It allows formulators to combine the fast surface cure of radical systems with the low shrinkage, deep through-cure, and dark-cure capability of cationic systems. As a result, the final material can achieve better curing efficiency, dimensional stability, adhesion, and mechanical performance.
The PF₆⁻ counteranion also plays a critical role. It is non-nucleophilic, which helps the generated acid remain active and prevents premature termination. In addition, the compound shows photobleaching behavior, allowing UV light to penetrate deeper into thick, pigmented, or filled systems.
Core Application Fields
Demand for 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate (CAS# 344562-80-7) is concentrated in four main areas:
- UV-curable inks and coatings
- Adhesives and 3D printing resins
- Photoresists and semiconductor manufacturing
- Electronic encapsulation and specialty materials
UV-Curable Inks and Coatings
This iodonium salt is a versatile photoinitiator for cationic polymerization of epoxy- and oxetane-based systems. It is especially effective in printing inks, white base coatings, and adhesives where thick films and high pigment loading make conventional radical photoinitiators less effective.
It is suitable for graphic arts, packaging, inkjet, and screen printing applications. The product enables rapid curing with low oxygen inhibition, which is a common problem in radical curing systems.
Adhesives and 3D Printing Resins
In adhesives and 3D printing resins, the compound supports hybrid free-radical/cationic systems. These systems combine the fast surface cure of acrylates with the deep through-cure and low shrinkage of epoxies.
This is particularly valuable in stereolithography (SLA) and digital light processing (DLP) 3D printing, where dimensional accuracy and layer-to-layer adhesion are critical. It is also used in lamination adhesives and structural adhesives for electronics and automotive applications.
Photoresists and Semiconductor Manufacturing
The compound functions as a photoacid generator (PAG) for deep-UV lithography. Its absorption maximum at 245 nm makes it suitable for KrF excimer laser lithography at 248 nm and other deep-UV applications.
It provides high sensitivity and sufficient acid generation for high-resolution patterning. It is used in chemically amplified resists (CARs), semiconductor fabrication, microelectronics processing, and MEMS manufacturing.
Electronic Encapsulation and Specialty Materials
In electronic encapsulation, the compound is used for epoxy resin curing, 3D printing materials, and rapid prototyping. Its low cure shrinkage and good thermal stability are valuable for electronic packaging that requires dimensional stability and heat resistance.
It is also used in photocurable coatings for optical fibers, display panels, and optoelectronic devices, where deep through-cure ensures complete polymerization in thick or filled systems.
Market Overview
The global market for 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate is part of the broader photoinitiator market. Growth is driven by the increasing adoption of UV-LED curing, the demand for solvent-free and energy-efficient processes, and the expansion of electronics, 3D printing, and semiconductor manufacturing.
International suppliers include IGM Resins, which offers the product as Omnicat 250; BCH GmbH, which offers it as IS051; Tokyo Chemical Industry, which offers it under product code M3379; ChemScene, which offers it under catalog number CS-0504229; and AK Scientific, which offers it at 97% purity under product code 9858EQ.
XinChem is a reliable manufacturer and supplier of high-purity 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate from China. XinChem offers the product as a 75% solution in propylene carbonate and in solid form, with stringent quality standards for UV-curable inks, coatings, adhesives, and photoresists. The company provides comprehensive quality documentation, batch-specific Certificates of Analysis, customizable packaging, and globally compliant REACH, ISO 9001, and GMP-aligned manufacturing.
Regional producers also supply the product in different purity grades and packaging sizes, but quality, documentation, and batch-to-batch consistency can vary. Buyers should confirm purity, solution concentration, storage conditions, and regulatory support before selecting a supplier.
Regional Market Dynamics
Asia-Pacific
Asia-Pacific is a major production and consumption region for iodonium salt photoinitiators. China hosts numerous manufacturers and suppliers, including XinChem. The region benefits from lower production costs, established chemical infrastructure, and proximity to fast-growing UV curing, electronics, and 3D printing industries.
Demand in China, Japan, South Korea, and India continues to grow, supported by electronics, semiconductor, and additive manufacturing sectors.
North America
North America remains an important market for high-purity and research-grade iodonium salt photoinitiators. Demand comes from the electronics industry, semiconductor manufacturing, and specialty chemical companies. Suppliers such as AK Scientific and ChemScene serve the North American market through established distribution networks.
Europe
Europe is characterized by strict regulatory requirements, including REACH registration, and a strong focus on quality and sustainability. European UV curing formulators, electronics manufacturers, and research institutions require high-purity photoinitiators with complete documentation. IGM Resins and BCH GmbH serve the European market with in-stock availability.
Japan
Japan is a specialized market for semiconductor manufacturing, deep-UV photoresist applications, and advanced electronics packaging. Tokyo Chemical Industry is a key supplier in this region.
Regulatory and Safety Considerations
4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate is subject to regulatory oversight in major global markets. Compliance with relevant regulations is essential for market access and trade.
GHS Classification
The compound is classified with the signal word “Warning.” Hazard statements include:
- H315: Causes skin irritation
- H319: Causes serious eye irritation
- H335: May cause respiratory irritation
Precautionary statements include P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, and P405. The product should be handled in a well-ventilated area with appropriate personal protective equipment, including lab gloves, safety glasses, and a lab coat.
Storage
Store in a cool, dark place, protected from light and moisture. For long-term storage, 2–8°C is recommended. The hexafluorophosphate anion is moisture-sensitive, so proper sealing and storage conditions are important.
Regulatory Compliance
In the European Union, the compound must comply with REACH registration requirements for import and use. Manufacturers and suppliers should provide comprehensive Safety Data Sheets and maintain appropriate documentation.
In the United States, the compound is intended for industrial and research applications and is regulated under TSCA. In New Zealand, it is listed on the New Zealand Inventory of Chemicals but does not have individual approval; it may be used as a component in a product covered by a group standard.
Transport Information
The compound is not classified as hazardous material for DOT/IATA transport under standard conditions. Proper packaging, labeling, and documentation are still required for international shipping. It is typically shipped at ambient temperature with protection from light and moisture.
Future Outlook
The outlook for 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate is positive, supported by growth in UV-LED curing, 3D printing, semiconductor manufacturing, and high-performance coatings.
Key growth drivers include:
- Expansion of UV-LED curing technology
- Growth in 3D printing and additive manufacturing
- Expansion of semiconductor and photoresist manufacturing
- Demand for thick and pigmented coating systems
- Increasing need for low-shrinkage, high-performance UV-cured materials
There are also challenges. The compound's primary UV absorption at 245 nm may require photosensitizers for efficient curing under longer-wavelength UV-LED systems. The PF₆⁻ anion is moisture-sensitive, so storage and handling must be controlled. As a specialized cationic photoinitiator, the market is smaller than that of commodity radical photoinitiators, and competition exists from other iodonium salts, sulfonium salts, and radical photoinitiators.
To succeed in this market, suppliers should focus on purity, solution stability, batch-to-batch consistency, supply chain reliability, regulatory compliance, and responsive customer service. Companies that offer high-purity products in solution and solid forms, flexible packaging, and technical support for UV curing, 3D printing, and photoresist applications will be well-positioned for growth.
Why Choose XinChem
Shanghai XinChem Co., Ltd. (XinChem) is a world-leading supplier of organic chemicals and specialty photoinitiators. The company serves the UV curing, electronics, 3D printing, and specialty chemical industries with high-quality 4-Isobutylphenyl-4'-methylphenyliodonium Hexafluorophosphate (CAS# 344562-80-7).
As a trusted manufacturer and supplier based in China, XinChem combines competitive pricing, reliable supply, and professional service. The company is a preferred partner for UV curing formulators, electronics manufacturers, and research institutions seeking this versatile cationic photoinitiator.
Technical Advantages
XinChem uses advanced manufacturing facilities and rigorous quality control to ensure purity, consistency, and performance. The production process includes established synthetic routes and counterion exchange with potassium hexafluorophosphate, enabling products with purity ≥98% on a solid basis and a standardized 75% solution in propylene carbonate.
Strict process control helps ensure consistent product quality, minimal impurities, and batch-to-batch reproducibility for UV-curable inks, coatings, adhesives, and photoresists.
Full-Chain Quality Control
Quality control covers raw material sourcing, in-process monitoring, and finished product testing. Each batch is accompanied by a detailed Certificate of Analysis documenting physical and chemical properties, purity, solution concentration, viscosity, density, and impurity profiles. XinChem offers batch-specific COA, customizable packaging, and globally compliant REACH, ISO 9001, and GMP-aligned manufacturing.
Product Advantages
XinChem offers 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate with purity ≥98% on a solid basis and as a 75% solution in propylene carbonate. The product’s high purity and consistent quality reduce the risk of side reactions and variability, making it suitable for deep-UV photoresists, thick pigmented coatings, and 3D printing resins.
Key specifications include:
- Molecular Formula: C₁₇H₂₀F₆IP
- Molecular Weight: 496.21 g/mol
- CAS Number: 344562-80-7
- Synonyms: Irgacure 250; Omnicat 250; HRcure-250
- Appearance: Yellow to brown clear liquid
- Purity: ≥98% (solid basis); 75% solution in propylene carbonate
- Density: 1.485 g/cm³
- Viscosity: 460 cps at 25°C
- UV Absorption Maximum: 240–245 nm
- Solubility: Soluble in cationic polymerizable monomers, methanol, chloroform
- Storage: Cool, dark place; protect from light and moisture
- GHS Classification: Warning; H315, H319, H335
Flexible Packaging Solutions
XinChem provides packaging options from laboratory-scale quantities such as 100 g and 500 g to industrial-scale packaging such as 1 kg, 5 kg, 20 kg, 25 kg, and bulk shipments. Customized packaging is available upon request, with appropriate protection from light and moisture.
Application Fields
As a dual-mechanism cationic photoinitiator, 4-Isobutylphenyl-4'-methylphenyliodonium Hexafluorophosphate (CAS# 344562-80-7) is used across multiple industries.
UV-Curable Inks and Coatings
- Key photoinitiator for cationic polymerization of epoxy- and oxetane-based systems
- Effective in thick and highly pigmented systems, including printing inks and white base coatings
- Enables deep through-cure and low shrinkage in graphic arts and packaging
- Suitable for use with photosensitizers such as thioxanthones for UV-LED curing
Adhesives and 3D Printing Resins
- Dual radical/cationic curing mechanism for hybrid resin formulations
- Low shrinkage and excellent dimensional accuracy for SLA and DLP 3D printing
- Lamination and structural adhesives for electronics and automotive applications
- Rapid prototyping and rapid manufacturing materials
Photoresists and Semiconductor Manufacturing
- Photoacid generator for deep-UV lithography
- Suitable for KrF excimer laser lithography and chemically amplified resists
- High sensitivity and high-resolution patterning
- MEMS and microelectronics processing
Electronic Encapsulation and Specialty Materials
- Epoxy resin curing for electronic packaging
- Photocurable coatings for optical fibers, display panels, and optoelectronic devices
- Low cure shrinkage and high thermal resistance for advanced electronic applications
Service Support
XinChem's team of experienced chemists and application engineers provides technical support from product selection and specification development to application guidance and troubleshooting.
Whether customers need help with photoinitiator concentration, sensitizer selection for UV-LED systems, hybrid curing formulations, or regulatory documentation, XinChem's technical experts are ready to assist. Custom synthesis and contract manufacturing with flexible scaling from R&D to commercial quantities are available upon request.
XinChem also provides global logistics support, reliable supply, and regulatory documentation, including Safety Data Sheets, Certificates of Analysis, and other required certificates. The company stays current with evolving requirements in major markets, including REACH, TSCA, and other regional regulations.
Frequently Asked Questions
What is CAS 344562-80-7?
CAS 344562-80-7 is 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate, a diaryliodonium salt cationic photoinitiator also known as Irgacure 250, Omnicat 250, or HRcure-250.
What is it used for?
It is used in UV-curable inks, coatings, adhesives, 3D printing resins, photoresists, semiconductor manufacturing, and electronic encapsulation.
Is it suitable for UV-LED curing?
Its primary absorption is around 240–245 nm, so photosensitizers may be needed for longer-wavelength UV-LED systems. It is highly valued in hybrid curing systems that combine UV-LED with cationic curing.
How should it be stored?
Store in a cool, dark place, protected from light and moisture. For long-term storage, 2–8°C is recommended.
Is it the same as Irgacure 250?
Yes. Irgacure 250 is a common trade name for 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate, CAS# 344562-80-7.
Contact XinChem
Website: www.xinchem.com
Email: [email protected]
WhatsApp: +86 18049800532
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