What Is Photoinitiator 369?
Photoinitiator 369, also known as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, is a highly efficient Type I (α-amino ketone) free-radical photoinitiator. It bears the CAS number 119313-12-1 and the molecular formula C₂₃H₃₀N₂O₂, with a molecular weight of 366.5 g/mol.
This pale yellow to slightly yellow powder appears as a solid at room temperature and is classified as a Type I photoinitiator, meaning it undergoes direct photocleavage upon UV exposure, generating active free radicals that initiate polymerization without requiring co-initiators.
Photoinitiator 369 is widely marketed under various trade names, including:
Omnirad 369 (formerly Irgacure 369) by IGM Resins
Genocure BDMM by Rahn
Speedcure BDMB by Lambson
JRCure 369 by Tianjin Jiuri New Materials
Doublecure® 369 by Double Bond Chemical Ind.
GR-369 by Hubei Gurun Technology
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Appearance | Slightly yellow powder |
| Purity (HPLC) | ≥ 99.0% |
| Melting point | 110 – 119℃ |
| Volatiles | ≤ 0.3% |
| Transmittance at 450nm | ≥ 90% |
| Transmittance at 500nm | ≥ 98% |
| Absorption peaks (in methanol) | 233nm, 324nm |
| EINECS No. | 404-360-3 |
| Storage life | 36 months (when stored properly) |
Data compiled from manufacturer specifications.
How Photoinitiator 369 Works
As a Type I photoinitiator, Photoinitiator 369 absorbs UV light energy and undergoes a unimolecular cleavage reaction, splitting into two reactive free radical species. These radicals then attack the double bonds of acrylate monomers and oligomers, initiating chain-growth polymerization that rapidly transforms liquid resins into solid, cured films.
What sets Photoinitiator 369 apart is its superior ability to capture long-wave ultraviolet light in the range of 350 – 380 nm. This extended absorption characteristic enables it to penetrate deeper into coatings and overcome the shielding effects of pigments, making it exceptionally effective for pigmented systems that challenge conventional photoinitiators.
Core Advantages of Photoinitiator 369
Exceptional Performance in Pigmented Systems
Photoinitiator 369 is specifically designed for pigmented UV-curable systems. Its high absorptivity makes it especially suitable for UV-curable inks, coatings, and photoresists, even those containing high levels of colorants. Unlike standard photoinitiators that struggle to cure through opaque pigments-particularly dark colors like black and blue-369 delivers reliable deep-layer curing.
Deep Curing Capability
The long absorption wavelength of 350–380 nm allows Photoinitiator 369 to penetrate thick film coatings from the inside out, ensuring consistent curing throughout the entire layer thickness. This makes it irreplaceable for applications requiring thorough curing of thick films on wood, metal, and plastic substrates.
Low Volatility and Low Odor
Photoinitiator 369 exhibits low volatility during processing and produces minimal odor after curing, an important consideration for high-end printing applications and consumer-facing products.
Broad Application Versatility
From graphic arts and packaging printing to electronics manufacturing and industrial coatings, Photoinitiator 369 demonstrates exceptional adaptability across diverse UV curing scenarios.
Application Scenarios
1. Graphic Arts and Packaging Printing
Photoinitiator 369 excels in offset printing inks, screen printing inks, and printing plate manufacturing. It is particularly suitable for curing dark color systems, including blue and black pigmented inks.
Recommended addition rates:
Offset printing inks: 2–4%
Silk screen inks: 2–4%
Color painting: 1.0–4.0%
For demanding applications requiring even faster cure speeds, formulators often combine 369 with co-initiators such as ITX, 184, 651, or 907 to optimize spectral response and initiation efficiency.
2. Electronics Industry
In printed circuit board (PCB) manufacturing, Photoinitiator 369 plays a critical role in solder mask inks and photoresists. It enables the formation of protective layers under UV light, delivering stable and reliable performance for fine-line imaging and high-resolution circuitry. The compound has been disclosed in patent literature for use in alkali-developable solder resist compositions and color filter resist formulations.
3. Industrial Coatings
Photoinitiator 369 is widely used in UV-curable coatings for wood, plastic, and metal substrates. Its ability to ensure consistent curing throughout thick film applications makes it ideal for furniture manufacturing, machine protection, and plastic product processing, where coating quality directly impacts product longevity.
4. Adhesives
For UV-curable adhesives requiring rapid positioning and final curing, Photoinitiator 369 is a premium choice. It delivers low yellowing after curing, making it suitable for high-precision bonding applications in electronics manufacturing-including smartphone screen bonding and optical lens assembly.
5. Emerging Technologies
Photoinitiator 369 is also adaptable to UV LED curing systems and photo-thermal dual-cure systems. Its absorption profile aligns well with near-UV LED sources, making it a forward-compatible choice for formulators transitioning away from traditional mercury-based UV lamps.
Formulation Guidelines
Recommended Addition Levels
| Application Type | Recommended Photoinitiator 369 Loading |
|---|---|
| Offset inks | 2.0 – 4.0% |
| Screen inks | 2.0 – 4.0% |
| Pigmented coatings | 1.0 – 4.0% |
| Photopolymers for imaging | 0.5 – 5.0% |
Data from IGM Resins technical specifications.
Synergistic Combinations
Photoinitiator 369 is often used in combination with other photoinitiators to optimize performance:
With Omnirad 184 (1.0–3.0%): Enhances surface cure in screen ink formulations
With ITX: Improves photospeed for high-speed printing applications
With 651 or 907: Broadens spectral response and fine-tunes initiation kinetics
Solubility and Compatibility
Photoinitiator 369 exhibits good solubility in active diluents such as TPGDA and TMPTA. For optimal dispersion, mild heating (40–60℃) is recommended during mixing. It demonstrates excellent compatibility with mainstream acrylate resins, including epoxy acrylates, polyurethane acrylates, and polyester acrylates.
Storage and Handling
Store Photoinitiator 369 in a cool, well-ventilated warehouse away from oxidants and food chemicals. Keep containers tightly sealed and protect from fire and heat sources. Standard packaging is 20 kg per carton. The product has a shelf life of 36 months when stored under recommended conditions. It is classified as non-hazardous for air, sea, and road freight.
Market Trends and Industry Outlook
Global Market Growth
The photoinitiator for UV curing market is experiencing robust growth. According to market research, the global market grew from USD 401.73 million in 2025 to USD 454.19 million in 2026, with an expected CAGR of 13.77%, potentially reaching USD 991.24 million by 2032. The broader photoinitiator market was estimated at USD 1.76 billion in 2025 and is projected to reach USD 3.25 billion by 2032 at a CAGR of 9.12%.
Specifically for Photoinitiator 369, the global market is forecasted to reach USD 18 million to USD 36 million by 2030, with a CAGR of 2.5% to 4.5%.
Regional Dynamics
Asia-Pacific dominates the market, with China leading both production and consumption. A major producer, Zhejiang Yangfan New Materials Co., Ltd., maintains a production capacity of 3,500 tons. The region is expected to see a CAGR of 3.0% to 5.0%.
North America projects a CAGR of 2.0% to 4.0%, driven by demand from the United States.
Europe shows more modest growth (CAGR of 1.5% to 3.5%), partly constrained by regulatory considerations.
Key Industry Players
IGM Resins: Global innovator in photoinitiators, marketing Omnirad 369 (formerly Irgacure 369)
BASF: Former manufacturer of Irgacure 369, now divested to IGM Resins
Zhejiang Yangfan New Materials Co., Ltd.: Top Chinese producer with 3,500-ton capacity
Tianjin Jiuri New Materials Co., Ltd.: Key Chinese supplier
Double Bond Chemical Ind. (DBC): Manufacturer of Doublecure® 369, headquartered in Taipei
Sinocure Chemical Group: Chinese manufacturer
Hubei Gurun Technology Co., Ltd.: Chinese manufacturer
Technology Drivers
Several transformative shifts are shaping the photoinitiator landscape:
Rise of UV LED sources: The transition from mercury-based systems to LED curing is driving demand for photoinitiators with optimized absorption in near-UV bands
Sustainability pressures: Environmental and health considerations are accelerating adoption of lower-migration, lower-toxicity initiators
Higher-performance demands: Growing requirements for thin-film uniformity and precision cure through pigments
Safety and Regulatory Considerations
Safety Profile
Photoinitiator 369 should be handled with appropriate personal protective equipment (PPE), including gloves and safety glasses. While it is classified as non-hazardous for air, sea, and road freight, detailed safety information is available in the Material Safety Data Sheet (MSDS) from each manufacturer.
The product exhibits low volatility and low odor characteristics, which improve handling during use.
Regulatory Status
A critical consideration for European customers: Photoinitiator 369 carries a CMR Category 1B classification by the European Chemicals Agency (ECHA). This regulatory status limits its use in Europe and may affect market growth in the region. Buyers in regulated markets should verify local compliance requirements before formulation.
Comparison with Alternative Photoinitiators
| Feature | Photoinitiator 369 | Photoinitiator 184 | Photoinitiator TPO | Photoinitiator 907 |
|---|---|---|---|---|
| Type | Type I (α-amino ketone) | Type I (hydroxy ketone) | Type I (acylphosphine oxide) | Type I (α-amino ketone) |
| Primary absorption | 324nm | 245nm, 280nm, 333nm | 275nm, 380nm | 230nm, 304nm |
| Best for | Pigmented/dark systems | Clear coatings | White/pigmented systems | Pigmented inks |
| Surface cure | Moderate | Excellent | Good | Good |
| Deep cure | Excellent | Poor | Excellent | Good |
| Yellowing | Moderate | Low | Low | Moderate |
Studies have shown that Photoinitiator 369 demonstrates higher photoinitiation efficiency compared to 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651) in real-time FTIR analysis of acrylic adhesive systems