1-Hydroxycyclohexyl Phenyl Ketone (184)

1-Hydroxycyclohexyl Phenyl Ketone (Photoinitiator 184) – High-Purity UV Curing Agent

Basic Information

• Product Name: 1-Hydroxycyclohexyl phenyl ketone (Irgacure 184 type)

• CAS Number: 947-19-3

• Appearance: White crystalline solid

• Melting Point: 47–50°C

• Boiling Point: 175°C at 15 mmHg

• Density: 1.17 g/cm³

• Refractive Index: ~1.5170 (estimated)

• Flash Point: >150°C

• Acid dissociation constant (pKa): 13.23 ± 0.20 (predicted)

• Solubility: Slightly soluble in water (1108 mg/L at 25°C); soluble in acetone, butyl acetate, methanol, and toluene.

Overview
1-Hydroxycyclohexyl phenyl ketone (commonly known as photoinitiator 184) is an efficient free-radical photoinitiator used in UV-curable systems. Upon exposure to ultraviolet light, it undergoes α-cleavage to generate two active radicals, initiating polymerization of unsaturated monomers and oligomers. It is widely used in various UV-curing applications due to its excellent reactivity, low yellowing, and good compatibility with many resin systems.

Mechanism of Action
This photoinitiator absorbs UV light (typically 250–360 nm), undergoes Norrish Type I cleavage to produce benzoyl and cyclohexyl radicals, which then initiate chain-growth polymerization. It is effective for both bulk and surface curing and is often used in combination with photoinitiators like 1173 (HMPP) to adjust cure speed and surface hardness.

Applications

• Coatings: Photocopying varnishes, plastic coatings, wood coatings, and paper coatings.

• Inks: Lithographic, screen printing, flexographic, and offset inks.

• Adhesives: UV-curable adhesives for glass, metal, and plastics.

• Electronics: As a photoinitiator in photoresists, solder masks, and electronic potting compounds.

Key Benefits

• High photoreactivity and good depth of cure.

• Low yellowing – ideal for clear coatings.

• Excellent solubility in common solvents and oligomers.

• Good thermal stability during storage.

• Compatible with acrylic, polyester, and epoxy acrylates.

Recommended Usage
Typical concentration: 2–6% by weight of the UV formulation, depending on the desired cure speed, film thickness, and pigment content.

Handling and Storage

• Store at room temperature in tightly sealed containers, protected from light and moisture.

• Stable under normal atmospheric conditions.

• Avoid excessive heat and direct UV exposure.

• Use appropriate personal protective equipment (gloves, safety goggles) when handling.

Packaging
Available in 500 g, 1 kg, 5 kg, 20 kg, and 25 kg containers. Custom packaging on request.

Quality Assurance
Each batch is tested for purity (HPLC), melting point, moisture content, and cure performance to ensure consistent quality.