4,4'-Bis(diethylamino) benzophenone, commonly known as EMK or by trade names like Omnirad EMK and Speedcure EMK, is a vital chemical compound with significant industrial applications, primarily as a photoinitiator. This article provides an in-depth look at its properties, chemical nature, and how it drives innovation in UV curing technologies.

The chemical composition of EMK is C21H28N2O, with a molecular weight of 324.46. Physically, it presents as a light yellow powder, with a specified melting point range of 93.0-95.0°C. Its chemical purity typically exceeds 99.0%, making it a reliable ingredient for demanding formulations. The compound is characterized by its UV absorption spectrum, with notable peaks at 248 nm and 374 nm, which are crucial for its function in photoinitiated reactions.

As a Type II photoinitiator, EMK operates through a bimolecular mechanism. Upon absorbing UV light, it transitions to an excited triplet state and then abstracts a hydrogen atom from a co-initiator, such as an amine synergist. This process generates the free radicals necessary to initiate the polymerization of monomers and oligomers in UV-curable systems. This mechanism makes EMK particularly effective in initiating polymerization of acrylate monomers and oligomers, finding extensive use in the formulation of UV-curable coatings, adhesives, and inks.

The versatility of EMK is further highlighted by its compatibility with various co-initiators and its effectiveness in both pigmented and clear UV-curable systems. This allows formulators to achieve desired curing speeds and final product properties, whether they are developing high-gloss clear coats or opaque, deeply pigmented inks. The typical addition amount of EMK ranges from 0.2% to 5.0% by weight, a factor that formulators must carefully control to optimize performance and cost-effectiveness.

Beyond its primary role in UV curing, 4,4'-Bis(diethylamino) benzophenone has historical and ongoing importance as an intermediate in the production of various chemicals. It is used in the synthesis of triarylmethane dyes, contributing to the vibrant colors seen in textiles and printing inks. Its role as a photosensitizer in the motion picture film industry and as a special optical material in microelectronics further demonstrates its broad utility.

When considering the purchase of this chemical, it is often described as a 'buy Photoinitiator EMK' option for businesses seeking to enhance their UV curing processes. Understanding its specific properties, such as its light sensitivity and recommended storage conditions (keeping the container tightly closed, dry, and in a cool place), is essential for maintaining its efficacy. The availability of EMK in different purities and packaging sizes from various manufacturers caters to a wide range of industrial needs.

In summary, EMK, or 4,4'-Bis(diethylamino) benzophenone, is a cornerstone photoinitiator in the UV curing industry. Its specific chemical and physical properties, coupled with its ability to effectively initiate polymerization in diverse systems, make it an invaluable component for manufacturers looking to improve efficiency, speed, and the quality of their UV-cured products.